Once in a lifetime opportunity.. 1982 CB1100R

It’s funny that someone had recently asked me about what my dream bike list was and after the highly sought-after RC30, I had mentioned the Honda CB1100R, which was sold in very limited quantities in non-US markets. They have that cool look of the vintage endurance racers from that era and were in fact built to satisfy the homologation requirements to race as a production-based machine in world championship events. The production numbers were approximately 500 in 1981, 1500 each in 1982-83.

Unlike the svelte 400 lb RC30, which is a 750cc street bike version of their highly successful V-4 racing machine, the CB1100R is based on the 1983 CB1100F street bike which was sold in the US and is a powerful, but hefty machine, weighing in nearly 518 lbs dry. The fuel tank is almost 7 gallons, so the wet weight increases dramatically. See: https://en.wikipedia.org/wiki/Honda_CB1100R for an overview. They were produced from 1980-83 and each version (B, C, D) has unique features that do not interchange with the other models.

Various articles have been written by others, and published, on the origins of the CB1100R, as per the below links. https://www.oldbikemag.com.au/honda-cb1100r-machine-mission/ https://classic-motorbikes.net/honda-cb1100r-rare-road-racer/ https://en.wikipedia.org/wiki/Honda_CB1100R

So, surprisingly, a CB1100R popped up on Facebook Marketplace and the posting gave “San Diego” as the location of the bike. The owner was a local Motorcycle Wrangler, as I would describe him. I had looked at some of his bikes when he lived in a different location some years ago. He was always turning over new stock and seemed to be able to find some unique bikes, but I had never worked a deal with him. More surprises were revealed when he mentioned that he had TWO of them for sale!

I made an appointment to go and see him and his current stock of machines. He had a Z1-R Kawasaki sitting out in front of his garage and mentioned that there were FIVE Kawasaki 750 Turbo machines stacked inside of a storage container. He was reluctant to reveal how he got his hands on two CB1100R machines with OR titles, but he just said that he was at the right place at the right time, overhearing a conversation at a local auction house. So, he snapped them up and posted them on Facebook.

The bikes were supposedly from the UK and showed the kind of “patina” that comes on bikes that are used and ridden in a mostly humid country. The key tag for the bike was a dealer item with the name of a motorcycle dealer in South Africa, though!

The brake lever pulled right to the handlebars and the plastic master cylinder reservoir was definitely showing its age. The bike supposedly ran, the inside of the aluminum tank was clean and the bike appeared to be fairly complete but weathered. It had pod filters on the carbs, but came with the stock air box and a new windscreen. The standard 4 into 2 muffler system had been replaced by a 4 into 1 collector, which looked fairly new. The tires were worn and one supposes that the drive chain and rear wheel dampers would need replacement. It was a project, but a very rare machine to be found anywhere in the US, much less right in SoCal.

One bike had already been sold, which apparently had 90k kilometers on it. The remaining one was showing about 46k which is about 28k miles. They both looked in similar condition, but the remaining one had its price reduced by $2k. I have owned several CBX six-cylinder machines and worked on several DOHC Honda 750-1000 machines when I was working at a Honda shop in the 1980s, so the engines are not unknown to me. They do have 4 valves per cylinder and after 40 years, the valve stem seals are undoubtedly hardened causing oil consumption. When cared for, the engines have a long life, but there have been instances of broken cam chains or tensioners leading to expensive repairs.

The basic 1100 engine was tweaked with hot cams and a 10:1 compression ratio so premium fuel is required to feed the 115 horsepower powerplant. The bikes were built to compete in 6-12 hour endurance races in Europe and Australia, so were not your average EPA-tamed powerplants.

Fortunately, Matt, the owner of the moment, agreed to deliver the bike to me despite not having any front brakes and we made a deal that I hope I will not regret. Be careful of what you wish for….

Arrival and evaluation.

Arrival:

Between the two of us, we managed to wrestle the big bike off of his truck and pushed it up onto my motorcycle rack without incident. Having only a long side stand, the bike wouldn’t stay on the rack as the stand end extended past the edges of the rack. Fortunately, I did have a rear bike stand which was slid up underneath the swing arm and raised the back wheel up centering the bike on the work stand.

Years of neglect were apparent, especially with the condition of the master cylinder, which had lost much of the factory black coating and the exposed aluminum badly corroded. I was able to disassemble the master cylinder and it will get a bath in phosphoric acid to neutralize the corrosion and then give a better view of the overall condition. I had already purchased a $40 repair kit for it, plus another $25 for the plastic reservoir so I hoped that it would be repairable.

The bike had gone down on the aftermarket 4:1 muffler, which suffered a pavement grind spot along the lower edge.

The bike did come with an Oregon title that had a strange VIN number that wasn’t from Honda. As it had no VIN number up where it belongs on the steering head, the only conclusion is that it has a new frame installed and the VIN number originated from Oregon. I actually reached the owner on the title in OR, but he was a wrangler as well and had no clear memory of the bike.

The bike had a loose combination of non-OEM nuts, bolts and other fasteners. The fairing and rear tail light assemblies are all mounted on little rubber mounts which incorporate 6mm studs for mounting. Two of the rear ones were severed and the fronts were missing altogether. Removing the gas tank was a revelation in that it was a 7-gallon tank that weighed just a few pounds due to its aluminum construction.

I was able to remove the carburetors and inspect them briefly. There was fairly fresh fuel inside and no signs of contamination or corrosion, so I didn’t go further into them. The intake manifolds were rock-hard and when the aftermarket replacements arrived, it was evident that the Chinese copies for $16 a set were just 4 copies of one of the four different part number manifolds used on the 900-1100 engines. The replacement OEM manifolds were $125 a set.

When the old manifolds were removed, there were trails of crystalized gasoline/oil in the ports, so it is hard to tell if that was old carb residues from sitting for many years or something more sinister. I’m sure that the valve stem seals need replacing. I did that once on a CBX by just lowering the engine in the frame and removing the cylinder head. That’s not possible in a 1100 chassis so the whole lump would need to be extracted from the chassis. The bike is sitting on a rear swing arm stand on my bike bench, only having a side stand to prop it up with, and because of the length, it extends past the edge of the bike lift.

Repairs

I was able to extract the rear wheel and have a new tire installed. The rear brake system was empty, so will need rebuilding like most everything else on this bike. I am not sure how I can support the frame to remove the front wheel and forks. The seals are leaking of course. The tire date codes were from 2011, so everything needs attention.

A gel battery was ordered, but was much smaller than the battery box. With the CBX bikes, there was a spacer that could be used to install a smaller battery than the GL Goldwing unit that takes up the whole space. I wound up using some wooden spacers to help secure the battery in the box, but it wasn’t the greatest remedy for the situation. I jumpered the solenoid and the starter motor spun the engine over okay.

Removing the instruments from the cowling, revealed a cheesy strip of metal that was used to hold them in place. The original steel instrument bracket was not included and are NLA hen’s teeth out in the world. The speedometer was removed as the reset trip meter was cockeyed and the reset knob and shaft were missing. The meter was sent to Foreign Speedometer who observed that the speedometer was similar to the later CBX units. In a desperate search for replacement parts, I contacted Tim’s CBX parts online and he sifted through a pile of old units coming up with just one that was a match. He kindly sold the unit for $50 including shipping to the speedometer shop.

Forks were disassembled and new seals installed, but the bottoms of the fork tubes were deeply scored with no apparent reason or source of why they would have become damaged like that.

I managed to wrestle both wheels off with the bike supported on jackstands under the frame. The rear wheel had a lot of corrosion which took about a half hour to remove down to the parent metal so the tire would fit the rim securely. The front wheel was taken to a local motorcycle tire shop and they swapped out the rubber with no comments about the rim condition. The only way I could remove the front wheel safely was to remove the axle clamps, pull each fork up through the triple clamps and roll the wheel out from underneath it all.

The master cylinder was successfully rebuilt and used to push out the right-side caliper pistons. They came out all blued with signs of severe overheating, either from racing or from sticking in the calipers and dragging the rotor for a while. A lot of the brake parts were shared with other models, many of which were for the CB900-1100F bikes.

Apparently, the brake calipers came from a related model, but the rear caliper pistons were 27mm instead of the 32mm specified. Using the microfiche parts illustrations on www.cmsnl.com was helpful to a point. There is a CB1100R Facebook page and a CB1100R owner’s page that requires a $25 subscription fee, but was worth it for the additional tech information it contained. Slowly all the brake components were rebuilt and installed. Bleeding the twin-piston calipers took some time, but finally, I got a front brake that worked.

The carburetors looked correct, but the codes on the bodies didn’t match what the owners on the FB site had to say about them. The clutch and twin throttle cables were replaced. I had to create a little piece to anchor the choke cable to the handlebar bracket which was missing.

With some new OEM 8mm fuel hose and a brass T fitting I was able to feed some fuel into the carburetors using a remote reservoir and the engine fired up! There is a bit of a rattle in the clutch housing which may be like that on the CBX models which used rubber cushions on the clutch basket. After years of service and age, the rubbers shrink and the cushion effect is nullified. The part number does trace back to the CB1000C and the CB1100F models.

I have to say that it would have been wiser to “Stay in my Lane” instead of having a fantasy of riding this brute on my Sunday rides with my Jamuligan friends. The combination of a lot of one-off parts, plus the condition of what was there has led to a lot of expense and effort, just to get it running and functional. There will be no “restoration” of the bike, but hopefully, there will be some DOHC wizards who desire to bring it back to its former glory. I’ll be keeping my 420 lb NT650 Hawk GT for my Sunday rides, probably forever. But it was an interesting experience to see what Honda’s race team conjured up starting from the CB1100F model and giving it the performance to win 6-hour endurance races repeatedly.

CB1100R anyone?

Bill Silver

aka MrHonda

11/2023

L’Orange CB77 from 1963 +1… Part 2

And the beat goes on….

I was called by the owner, described above, in early Dec. to see if I could help him with repairs to the CB77. He had sold both the 1963 CB77 and a 1966 CL77 to the same owner in nearby Rancho Santa Fe. He sent photos of a large pool of oil beneath the CB77 and maybe a little leak beneath the CL77. The new owner was requesting assistance in getting the oil leaks repaired as soon as possible.

I was going to be in the general location (about 40 miles from home) for my monthly chiropractor visit, so it was convenient to swing by and have a look. It wasn’t pretty….

I had never seen that kind of oil leak beneath any 250-305 before, unless the drain plug was loose and the bike sitting for weeks. I had brought tools and the previous owner supplied some oil seal kits so I could hopefully do an on-site repair and head on home. After a quick view, it was obvious that the bikes needed to come back home with me for repairs. The new owner had left the key in the PARK position, so the battery was completely dead. 

The oil leak was drooling from the shift shaft seal, which is an easy replacement, but the oil smelled of gasoline which apparently leaked into the crankcase before the last ride. Somehow, the gas-oil mixture didn’t ignite when the bike was operated and then shut down. The diluted oil leaked past what was probably the original 60-year-old seal and drained the crankcase down to where the level was nearly at the seal level in the clutch cover. Thus the large pool of oil beneath the bike.

Both bikes were loaded up into the Tacoma and hauled back to Rancho de Honda for repairs. The next day I changed out the shift shaft seal, then drained the oil as the drain plug appeared not to have a gasket installed. What drained out was watery, dark-colored oil that reeked of gasoline. I had also replaced the crankshaft seal and was putting things back together when I turned the engine over with a wrench and heard a god-awful squealing sound emanating from the engine somewhere up high. It was one of those fingernails on the chalkboard kinds of noises, which got louder when the spark plugs were removed. My best guess was that the diluted oil had caused some kind of metal-to-metal damage and that the engine would need to be removed for inspection and repairs. After the findings were relayed to the owner, permission was granted to move on to the repairs.

I did pull the clutch cover off, just in case the primary chain nut was backing off or something else was loose under the cover. I did find the oil filter was tight on the shaft and that the outer clutch pressure plate was contacting the inside of the clutch cover, too. The filter needed servicing anyway. Clearance was provided so it spun easily on the shaft as normal.

Once the engine was out, the top cover was removed and the crankshaft was turned again to try to pinpoint the squealing noises. The top end looked pretty dry, but nothing horrible stood out. I shot some WD40 into the cam bearings, where I thought the noise might be coming from, but it didn’t have any effect.

The cylinder head was then removed and the noise became centered on the pistons and rings. The cylinder walls were dry and the rings were dragging against the cylinder walls metal-to-metal. I suppose that if I had just shot some oil down the spark plug holes when it was still assembled, the noise would have been reduced and that would have pinpointed the cause of the noises. Still, there was evidence of the head gasket leaking up front and around the edges, so it was best to just go through the top end anyway.

The speedometer was showing less than 9k miles and the relative lack of carbon buildup on the piston crowns and valves seemed to reinforce the truth of the miles shown. The ring gaps were not terribly excessive, but the to edges of the rings were worn sharp and several of the rings were sticking in the ring lands of the pistons. The pistons were free to swing back and forth on the rod ends, but the piston pins, themselves were immobile when the clips were removed. Again, I give thanks for finding the Benelli piston pin removal tool that I had bought a few years back when I owned a Benelli Sei. Using the tool to its fullest the pins begrudgingly gave way to the tool’s force and were removed. One pin had an odd wear spot on the middle of the pin, but mostly they were undamaged. Piston pin fit is normally a finger push fit into the piston pin bores, so it is unclear why these had become so tight. I have a bottle brush hone that is the right side to open up the pin bore holes and it was used to allow a proper pin fit.

I had the cylinders honed at my local machine shop and ordered new STD piston rings from who turned out to be a former San Diego friend who moved to Minnesota a few years ago. While waiting for the parts, I disassembled the cylinder head, checked for any damage, touched up the exhaust valve seats, and reassembled it all.

When I turned to the round bowl carburetors, I discovered that someone had sealed up the overflow tube on one float bowl and that the main jets were #125 instead of #135 specified. The float levels were set at 26mm instead of 22.5mm so perhaps the bike had lived in high altitude for part of its life. The carb insulators were RTV glued onto the carburetor flanges and cylinder head. The more you look the more things wrong you find, in many projects like this.

The float bowl overflow tube had a split down the side causing a fuel leak, which was soldered for repair. The floats were original round bowl types, which come close to the side walls of the float bowl. I had many leftover round bowl gaskets from kits which contained both round and square bowl gaskets. Sadly, most of them had come from Keyster kits and they are just not made correctly to OEM specs. When the bowls were removed, the gaskets were cork and had shrunk up quite a bit. I ordered new floats from 4int1.com along with their swell-proof gaskets.

I had already removed the clutch cover, so I thought I better check the clutch plates. They were, of course previously stuck and there was rust embedded into the steel plates. Oddly, the outer pressure plate edges were sticking up proud of the edges of the clutch basket, instead of just tucked under the edges. This stack height apparently led to the contact marks inside the clutch cover. All the plates seemed to be of the right thickness and number (it was a 6-plate clutch), so I decided to mix-match the clutch pack with some thicker 268-020 plates, just fewer of them. In the end, it was a little shorter than normal, but it will clear the clutch cover now. We’ll see how that works out in the end…

I cleaned the carb insulators of the black RTV that was coated over them and installed new Honda 260 code o-rings on the insulators and the carburetor flanges. The cleaning process always involves flattening out the flanges, changing the o-rings, and checking for any tendencies for the slides to stick in the carb body bores. The main jets will be bumped up to #140s, which seem to work better on today’s E10 gasoline, which causes engines to run lean on standard settings.

When the engine was installed, I tried to quick-fire it up, but it backfired and spit back. The coils were tightly grouped together and the leads crossed each other. Swapping them back got an initial startup, but the ignition timing was incorrect. When the right side points were adjusted, one of the point screws was stripped in the hole, so a substitute point plate was acquired and installed. After picking up a fresh set of D8HA NGK plugs and raising the needles up a notch, the bike finally fired up and settled down to an idle. The throttle cable was a bit cranky and the cable adjuster on the right side carb is raised up more than the left to get them synchronized.

The last step will be to replace the old floats with the square bowl types that have more clearance around the edges, so they don’t interfere with the float bowl gaskets. Of course, the petcock needed to be rebuilt including the brass tube that was down to about an inch high.

On top of it all, the tires are old and the drive chain needed to be replaced. I did find an inexpensive new 530 pitch drive chain and installed it before placing the kickstarter cover back on the engine. Setting the clutch adjuster with the new clutch pack setup actually caused the alignment marks to be just about right. The tire pressures were 18/12 psi when I took it around the block, very slowly.

The co-conspirator….1966 CL77

This bike came down with the 1963 CB77 for a checkover and a small oil leak complaint. It was parked next to the CB77 in the garage, adjacent to the large pool of oil/gas on the floor. I had gone through the bike earlier in the year after it had been sitting for about 10 years. It required the usual fuel system clean-out, a new battery and, and overall tune-up procedures.

I had ordered a pair of the pushrod seal retainer kits from the Cappellini dealer on eBay. The first one went on the CB77 after the extensive rebuild. This second one should have been a 15-minute parts swap but turned into over an hour due to discoveries beneath the kickstarter cover.

First, the two 6mm counter shaft plate screws came out very hard, perhaps installed with Loc-Tite. After I removed the screws, I wanted to clean up the threads for the new retainer screws. The 6mm tap went in about half-way on both sides, then sheared off when I was trying to get that little bit of extra thread clean-up. There’s no getting broken off taps out of a hole like this, apart from an EDM machine. Fortunately, I had a spare shallow spline sprocket that was in decent shape. So, that problem was solved. HOWEVER….

When the sprocket was pulled from the countershaft, I was amazed and horrified to see that the countershaft seal was partially hanging out with a large open gap between the engine case and the edge of the seal. It had been installed with some of the Permatex Moto-Seal or Honda-bond liquid sealer when the engine cases were bolted back together again. Whoever did it, failed to notice that the seal had squeezed out at an angle and was left in that condition. Not only that, behind the rotor there was JB Weld, right where the engine cases get damaged from failing to locate the crankshaft main bearing in the knock pin correctly.

It’s hard to know if the damage was done before the last engine work or during the assembly of it. The possibilities are that the bearing was reset and the oil hole was not blocked. The other scenario is that the bearing was left in the out-of-indexed location, which blocks the oil flow to the crankshaft bearing. The builder might have noticed the cracked engine case and just sealed it up, rather than dive back in to reset the bearing properly.

The bike has straight CL72 exhaust pipes with the Snuff-or-Nots installed at the back. They knock down the noise a little bit but I’m sure that the neighbors would prefer that I not run the bike around for long. The bike repair work was done, but was waiting for the return of the speedometer repairs from Foreign Speedo in San Diego, my go-to guy for vintage Honda speedometer repairs.

When the bike was ridden the speedometer needle was whipping around and scratched the faceplate. Fortunately, Foreign Speedo has a guy in San Diego who can silk-screen the faces back to their original condition, so there is a time lag when he comes to pick up various faceplates and when they are returned. The bike runs out very strong (and loud), so the speedometer is all that is needed to return it to service.

The bikes are scheduled to be returned on Dec. 28 in much better condition than when they left the owner's garage. 

Just another few weeks in the life of MrHonda...

Bill Silver

12/23

L’Orange CB77 from 1963… Part 1 (the Prequel)

I recently received a call from a local (25 miles away) man who wanted me to come by and have a look at his “all original” 1963 CB77 305 Super Hawk. He had owned a lot of bikes of various makes and models but wasn’t fully dialed in on vintage Honda twins. He wanted an expert opinion about the overall originality and what it might need to fetch a good sales price. I agreed to swing by on my way to a nearby doctor's appointment and have a look. He had sent a string of photos to my phone, but they don’t really give a full impression of a lot of critical details on these models.

On arrival, I saw the bike down in his ground-level garage, sitting next to a fully restored Bultaco Matador. As I approached it was obvious that this formerly Scarlet Red model had been exposed to a little too much sunlight which turned the factory lacquer Scarlet red paint into a dull pumpkin orange color. So, “points off” right away. The bike had been modified with a set of what appeared to be CL72 handlebars, with matching higher cables, but mysteriously had the “Diamond” pattern hand grips that are normally seen on 1961-62 machines. This bike was a 3112xx series 1963 model, which you wouldn’t expect to find those grips on a bike of this year's model.

The front tire was an original OHTSU deeply ribbed unit that was certainly used on original CB77s in the early years. The rear tire had a pretty correct-looking tread pattern, but it was an IRC tire, so obviously not the original, especially with 8900 miles showing on the speedometer.

The bike featured the original stainless steel stock mufflers, but both had been cracked and repaired just behind the top mount where the muffler bolts to the footplate bracket. This is a common failure seen with stainless mufflers and even stock chromed steel ones where the top mount bolt was installed. I always leave the top mounting bolt out for this reason on all of my bikes.

Moving along, I noticed two different keys on the ignition switch key ring. One was an expected large head T series key, but the other one was one of the small head versions. When I looked at the steering lock, it had a different key number than the other two keys! When we turned the power ON at the switch, the neutral light was not functioning and the headlight didn’t come on when that headlight switch was flicked to ON position. The tail light did work in both tail and brake light functions, though.

Looking over the engine cases, it is clear that the clutch cover, oil filter cover and dyno cover were all painted over instead of being the original finishes. I was surprised to find the camchain tensioner with the adjustment bolt on the left side, which was an early feature of the engine series.

A closer look at the fenders and side covers revealed that they were a repaint in something like Cloud Silver, but with a flatter final tone.

The seat cover looked very fresh with Honda-like texture on the material, but there was no HONDA on the back and once we were able to remove the seat from the chassis, it was obvious that it was a re-cover from several details where the cover was glued on and not fitted just right. It did have the outside seat strap buckles in place. Removal of the seat was a chore as the forward two mounting posts, which are welded to the battery box edges were both bent inwards about 5 degrees. They jammed the tabs on the front of the seat pan, making installation and removal quite difficult. A closer inspection revealed a re-welded battery box to the frame, apparently replaced due to battery acid damage way back in time. Ironically, where the welds were done, the paint was touched up with matching orange paint.

We were unable to start the engine, due to some fuel feed issues. He was going to take the bike to a local motorcycle mechanic friend for some electrical repairs and to get the bike started up again. The dimmer switch select knob is rather sloppy and doesn’t feel like it is doing its job for the high-low function.

Also noted, is that the kickstarter arm was wobbly on the kickstarter cover bushing, somewhat consistent with the mileage shown on the speedometer and probably aggravated by a lot of kick-starting efforts in the past. When these bikes are tuned properly and have a fully charged, load-tested battery in place, they seldom need kick-starting at all. I would suspect that the starter clutch springs have collapsed and the starter clutch rollers are slipping on the clutch hub.

Also noted was that the position of the clutch adjuster index mark was off to the right, quite a bit indicating that someone had changed the clutch pack stack height. This coincides with the clutch cover paint job and the obviously damaged screw heads done when the cover was removed in the past.

There was a very unusual aftermarket side stand assembly mounted to the frame. It didn’t tie into the normal mounting points on the lower frame section and didn’t require the longer YB center stand bolt which is needed with OEM side stand bracket mounting. The side stand arm was black and had a flared end vs the normal little peg that was welded to the original side stand parts.

On the plus side, the original cloth tool pouch was present with most of the correct tools. The correct Dream 300 tank badges were still in good shape, despite the ozone weathering of the chassis paint. There is a box with a NOS set of OEM flat handlebars, cables, dimmer switch and a few other little tidbits to convert the bike back to original flat bar configuration. The CA Black plate license plate seems to be in the correct series of numbers for 1963 registration.

Overall, it seems to be a low-mile, mostly original CB77, with shortcomings in the faded paint, welded mufflers, polished covers that were painted-over, unknown clutch work, improperly welded battery box/seat mount fittings, and incorrect handlebars/cables. Once the bike is up and running again, more attention can be put upon the running condition, as far as noises, compression checks, clutch function, transmission function, ignition/fuel system functions, etc.

Bill Silver aka MrHonda

April/23

https://bringatrailer.com/listing/1963-honda-cb77-super-hawk/ for photos and details

 Too much friction spoils the party…

In bringing the CB350F back to life, I noticed that the forks were pretty stiff upfront. Hitting small bumps would just push the front end of the bike up like it was a rigid fork machine. The fork seals were leaking anyway, so I pulled the forks off, re-sealed them, and filled them with some synthetic ATF from the auto parts store.

From: https://vorsprungsuspension.com/blogs/learn/what-is-fork-stiction

Stiction: an abbreviation of “static friction” - the friction between stationary surfaces at rest, which resists them beginning to slide over one another.

Friction: the resistance that one surface encounters when sliding over another. Generally speaking with suspension this refers to “dynamic friction”, ie the frictional force while already in motion

Nothing was bent or damaged on either fork, but when the whole front end was reassembled, it still rode like an empty 1-ton pickup truck. I had already changed the worn-out rear shocks with some slightly longer aftermarket copies, but that didn’t do a lot to improve the ride quality.

My recollections with re-assembling 1970s Honda street bikes, even after a tire change is that the fender stay mounts are not precisely fitted and it has been my belief and experience that when you force the fender stay into the insides of the fork sliders unnecessary friction/stiction is induced onto the fork suspension system.

With the CB350F, I removed the front axle and nut, tightened them together, and then mounted one end into the bottom of the fork slider, secured with the two nuts on the cap. With both fork tubes set about evenly at the top of the fork crown, there was a gap of about a 16/th of an inch above one end of the axle in the opposite slider. I loosened the fork tube on that side and tapped it down until the slider just rested back on the end of the axle. This keeps both sliders at the same level, preventing binding on the fork bushings. See end photos.

Secondly, when I bolted the fender stay to the right side slider, opposite of the disc brake mounting hardware, a gap was clearly seen between the fender stay and the fork slider/brake hardware mount. I added two 6mm washers on the front bolt and one at the back to keep the fender stay from pinching the fork sliders together, causing fork bushing binding.

The front and rear fender stay bolts were loosened up to allow the ends to center themselves on the bolts. I also loosened up the fender stay mounting fasteners to the fender itself. The goal is to allow the fender to just float in between the fork sliders, moving as a unit up and down with minimum amounts of friction caused by side-loading the sliders against the fork bushings.

There are super slick fork seals, fork seal grease and fork oils that are all designed to lessen the friction and stiction in the front suspension. All of these things can help to allow freeer movement of the front forks during compression and rebound motions.

Honda and most other manufacturers were not fully cognizant of the dynamics of fork action in the 1960s and early-1970s, with most of them having little rebound control. Progressive wound fork springs can be helpful in allowing more initial movement of the front end when encountering small bumps. Changing the whole spring rate is sometimes necessary. Most bikes were designed with the maximum load rating in mind, which is generally too stiff for a solo rider of average weight.

Any or all of these things can cause fork binding that wears the fork bushings and inside of the fork sliders unnecessarily. Take time to carefully look at how the front forks and fender are fitted to the bike to minimize suspension travel problems.

Just refitting the front fender to the forks, as described above, allowed for a noticeable improvement in the ride quality on this particular bike.

Bill Silver aka MrHonda

11/20/23

It’s a DADs bike… 1973 CB350F revisited-Part 2

 Part 2

The bike didn’t stay intact for very long. I put it up on the workbench and proceeded to dismantle the bike’s exhaust and carburetors to allow the disassembly of the top end to find out what the source of the oil leak was and rather uneven running at idle. Visually, the tach drive seal had been leaking for a long time and drooling oil down the front of the engine.

As the cylinder head was removed, it became apparent that the head gasket had blown out between the number 3 and 4 cylinders. This is highly unusual in my experience, especially having raced 350 and 400F models under severe conditions. Here was a stone-stock model with a burned fire ring and adjacent gasket material. The combustion chamber was carbon-ed up, as were the valves with burned oil, but the cylinder bore looked completely fine and just like the other three.

The cylinder head had a depression and signs of some erosion from the blown head gasket area. I measured the depression to about .004” and sought out a machine shop that could shave off about .006” to flatten out the head and erase the low spot between cylinders.

I took it to a local automotive machine shop but they were unable to jig the head up in their machine, so they walked it down the street to another machine shop to see if they could do the deed. I suppose that you might be able to skim-coat some JB weld down in the valley and coat the gasket with some sealer to ensure a good connection, but that would be a last-resort effort. Certainly, another cylinder head would be available on eBay, but you never know what you will get in a used part like this.

Trials and Tribulations….

Well, the second machine shop did a beautiful job of skimming off just a bit of the uneven cylinder head surface, so all I had to do was to remove the rest of the valves, de-carbon them, change the valve stem seals and put it all back together again. Reassembly is pretty straightforward on these engines, which are easy to work on in the frame. After I got the top end back together and the valves adjusted, I checked the compression readings which were all about 150 psi. I left the pistons/rings alone as the bores looked pretty clean, but it does have 17k miles on it, so we’ll see how it runs and if it wants to use some oil. The valve stem seals were definitely cooked, so the new ones will reduce oil burning quite a bit.

The carburetors were split apart enough to replace the o-rings on the fuel fittings that feed gasoline across the four carbs from a central point. I had to drive out the shaft that had a couple of keys in both ends to engage the throttle arms. In the process, one of the copper bushings got damaged and they are not a separate part from the base plate. I went on eBay and found a copper bushing that was 3/8” x 1/2” by 3/4” which is actually the size of the OD and length. The ID was a little bit tight so I drilled out the inside with a drill bit of a close size and it all went back together again. The float bowls and jets were all ultrasound cleaned and the o-rings were replaced from my handy K&L Keihin carb repair kit box.

Again, the float settings for the carburetors were off more than a bit. The last set for my friend's CB350F was much worse, though. 

The next challenge was to install new aftermarket intake manifold rubbers. There are two different part numbers used on 1-4 and 2-3, but they are slightly different shaped and I spent a half hour trying to get the carbs pushed into place, thinking that the little part numbers indicated on the manifold faces were all to go down. Finally, I had to remove them from the head, push them onto the carb spigots, and turn them until the spacing matched the intake port dimensions. In the end, the two left sides were installed with the lettering down and the two right sides were installed with the letters up! The carbs slipped into the manifolds securely and the next job was to install those shiny new 4:4 mufflers, which were worth more than the bike.

I had installed a set of these for a friend, when they were available about 5 years ago, and recall having some problems getting them to fit up to the brackets properly. I started with the left side 1-2 pipes, which are bolted together at the rear along with the interconnection gasket. When I tried to get the flanges and collars to fit up into the cylinder head, they wouldn’t go deep enough to get some threads for the 6mm nuts to tighten them up. I did finally get the #2 pipe into the head with the stock collars, but the #1 was not having it. I dug through a box of misc flanges and collars and came up with 4 that were the right OD but about 1/4” shorter in height. These eventually allow the #1 pipe to be fitted into the cylinder head, along with a fresh exhaust pipe gasket.

Then the problems really began as the rear mount which incorporates the rear footpeg was about a 1/2” off center from where the bolt goes through the footpeg and the exhaust bracket then to the frame mount. I tried to adjust the stud holes that attach the two pipes together but it wasn’t going well. Finally, I loosened the flanges a bit and pulled the rear bracket up so the bolt would go through. Not only was it off in height, it was about a 1/4” outwards leaving a gap to fill in. Eventually, I was able to bolt everything up, but the pipes were in a bit of a bind. I think that they missed the mark on bending the header pipes correctly which caused the misalignment at the rear.

When I looked at the right side pair, before installation, I compared the flanges of the old and new pipes and discovered that the old pipe flange was welded flush with the pipe, leaving a nice 90-degree corner for the collars to push up against them to hold into the cylinder head port. The new ones had thicker flanges that were welded in where the flanges would normally rest, causing them to appear to be too short to install. I used one set of the shorter collars on one pipe and wound up cutting down the stock set about an eighth of an inch to allow for the flange problem.

Again, when the headers were bolted into the exhaust ports, the rear bracket was a little low and about a half inch outwards away from the frame mount. I installed a set of thick washers to take up the space and sourced a longer bolt to finish up the installation. I spent more than 4 hours just trying to fit up the exhaust system and even though they are nice and new and shiny, they really don’t fit the bike properly.

The mufflers had little stickers that were from QC and said “checked” but I am not sure that whatever they checked was accurate. Anyway, they are on the bike. I did start it up on a remote bottle to see how it would run now but there were some lingering carb problems that needed to be addressed before a good test ride is undertaken.

I removed the carbs again and switched the connecting shaft around 180 degrees to get the keyways and shaft machining oriented properly. The damaged bushing left a little bit of extra slop in the system, but they worked much better this time. However, when I put the gauges on them to sync all four, the #3 slide adjustment wouldn’t sync with the other three. I carefully dismantled the #3 carb top and extracted the slide to check for any irregularities, then reset everything once again. Finally, they were all reading the same and the idle smoothed out considerably. If the #3 slide was always higher than the other three, previously, that might explain the overheating of that cylinder and the head gasket failure.

Two things led me to think that the brake shoes and points were all original to the bike at 17k miles. The rear brake rod needed all the adjustment used up to get the rear brake to function properly, which generally means that the shoes are all worn down. For riders who have some fear about heavy use of front brakes, often wear out the rear brakes prematurely because that is their main source of stopping the bike. Imagine my surprise when I removed the brake panel and found the shoes to be at close to 4mm, which is apparently the stock thickness. I had purchased a set of Vesrah aftermarket brake shoes from an eBay seller and they came out of the box at 4mm! So, once installed on the bike, the rod adjustment nut is still mostly threaded all the way up. There is a pedal adjustment to lower the standard height setting, so that will affect the adjustment nut setting, but normally it should be way at the end of the rod when everything is new. Perhaps, the drum is worn out, which seems unlikely.

In adjusting the ignition timing, I had to rotate the backing plate all the way in the adjustment slots in order to retard the ignition timing at idle and it was still going a bit past the full advance marks. Looking at the point gaps, they were down around .008” instead of the normal .012-.016” range, which indicates that the rubbing blocks were all worn down from 17k miles of operation. Normally, the points should be changed about 12k miles, so they are undoubtedly the originals from 1973. I ordered one of the inexpensive Chinese-made electronic ignition plates and that should stabilize the ignition timing.

Apart from replacing the tires and drive chain, all it needs is a really good detail and polish to bring it back to its former glory. I think that the previous, now deceased owner would approve of my handling of his precious CB350 Four.

Bill Silver aka MrHonda

10/11/23

PS

The carbs had to come off again as the linkage bushings were allowing too much play. I bought a used bracket plate from an eBay seller and also re-jetted the mains to #78, up from the stock #75 sizes. This, coupled with the newly installed e-ignition allowed the bike to run smoother with a bit more pep. The carb synch went well and all four are staying equal with each other.

I wound up replacing the fork seals, as they were the originals and weeping a bit. I put the bike into my name and registered it. It gets ridden a few times a week, but the suspension is still rather rough for me. My Sunday ride is a 1991 NT650 Hawk GT and I really enjoy that bike. So, the 350F will go on the market and hopefully to a good home where it can be appreciated for its glory after 50 years.

It’s a DADs bike… 1973 CB350F revisited-Part 1

Part 1.

I have owned a few of these bikes, including one that I bought, brand new, in partnership with my step-dad, Ray. I got out of the USAF in 1971 and had a few odd bikes afterward. Dad got started riding when my Mom bought him a 125cc Wards Riverside 2-stroke single that was on sale for a couple of hundred dollars brand new. He rode it sparingly and then somewhere bought an orange and white CL350 paint shaker Scrambler to ride to work. When the CB350F was released in 1973, we decided that this was the bike for us. The bikes came in sparkly Red and Green paint schemes. We chose the red one.

We shared riding it for a while, then he picked up a green 1976 CB750A. He switched the oil to a synthetic brand and noticed that the bike ran cooler and maybe a little quieter. They are a heavy bike, so after I had bought a new 1978 CX500 and rode it for a few thousand miles, he bought that one from me and enjoyed the low-maintenance ride. But, back to the CB350F.

We wrangled a deal with the local Honda dealer, for something like $1400. They were lighter and smoother than any of the previous bikes we had experienced, but it was kind of slow compared to the CB/CL350 twins of the time. The CL350s were geared a little lower than the CB350s and that just made them shake even worse. Out with the twin and in with the Four!

I borrowed it one weekend and drove it all the way into LA to see my girlfriend who I met before I went into the service in 1967. We kept in touch over the years and she invited me up to visit for the weekend. The freeways were a little tamer back then and I didn’t give much thought to running the bike up 100 miles each way.

After not too long, those cute little four-pipe mufflers started to corrode from the inside, so the “fix” at the time was to saw off the header pipes at the muffler weld joint and install the slip-on 4:2 RamFlow mufflers, which were noisier and probably didn’t do much for the power output. But, they were cheaper than buying a full set of OEM mufflers at the time, so that is what happened.

When the CB400F came out, a quick test ride made the CB350F obsolete immediately, despite the same engine architecture, but the new 6-speed transmission and the 4into1 exhaust system were too seductive to ignore. So, I bought a new CB400F and Dad kept riding the CB350F for a few years.

When I was road racing, back in the 1970s, the AFM club sponsored a 6-hour endurance race at Ontario Motor Speedway. The first one was in 1978. I had been racing 125s, having won the 125 Production Championship on a CB125S1. I had raced the CB400F for a few races, then sold it to my brother who put over 30k miles on it. So, at the time, I didn’t have anything to ride in the 6-hour until I happened upon a running, but somewhat sad CB350F for sale at $500. I still had a Yoshimura R&T camshaft, an electronic ignition that came from my CB400F. I had Rob North roll up a reverse-cone megaphone to fit onto the aftermarket 4into1 exhaust pipe. I added a new pair of Dunlop K70 tires and put it all together just in time to sign up for the race.

It was probably the slowest bike in the entire field, but when the race began, it started to rain! The bike, not having a lot of power and fresh tires stayed on the track without difficulties while others were sliding off under power in the tight turns. Even with all of the speed goodies installed, the bike still wouldn’t go over about 95 mph. It did get about 30+ mpg under race conditions, so we only had to stop for fuel about every 100 miles. Eventually, the track dried out and we carried on, eventually getting a top 10 result in our 350cc class with the slow, but reliable CB350 Four.

I have several friends who currently own CB350F bikes. One bought up one of the $1600 sets of reproduction mufflers from CMSNL about 5-6 years ago when they were available and I installed them on his bike. They really sound lovely, when the mufflers are all intact and certainly look the part of a performance machine.

My other friend picked up a 4-pipe CB350F from Mecum auctions in 2022, but stored it in his storage unit without ever riding it at all. There is a story on my www.mrhonda.guru blog page about that bike and its problems with carburetors and an electronic ignition failure.

Truthfully, I have watched the auction prices skyrocket lately on these bikes when they come up with stock pipes, especially. Most of the ones I have seen for sale, locally, were in sad shape with faded paint, cracked or missing side covers, aftermarket exhaust pipes and a round or two of road-rash from crashes in the past. With all I have going on lately; the CM185 Twinstar twins and a CL77 engine rebuild (story coming), I really don’t go hunting for CB350 Fours. Then, Facebook Marketplace posted one that was too good to be true.. or was it?

Seller's Description

1973 Honda 350 Four. Has new battery. Comes with new exhaust pipes still in the box. Starts up and runs but leaks oil. I have to many other projects going on so I don't have the time to spend on it. 

                                                CB350F after the new pipes were installed.

Well, that caught my attention, so I sent a message on Messenger asking if I could set an appointment time to come up and buy the bike. The bike had been listed for 12 hours and I figured that the seller would be swamped with messages and offers to buy it. Perhaps, one of the detractions was that the bike was in Murrieta, CA which is about 75 miles away from me down in Spring Valley. It’s a good 1.5-hour drive each way if you are lucky to miss the afternoon traffic crunch going northward.

To my surprise, the seller replied from work and said that he could meet me at 2pm. I told him that I was coming with cash and a truck and I didn’t have to ask permission from a wife or other significant other. He laughed and said come on up! He even sent photos of the mufflers still in the boxes, to confirm that they were part of the package and not some aftermarket system. Well, I couldn’t get up there quick enough!

The backstory for the bike was it belonged to his Dad, who had passed away recently. Dad had a Mustang Convertible, and a Baja Bug, both of which had been sold, and this shiny red 1973 CB350F left to sell. I had mentioned that I had owned one when they were new, along with my Dad and that made him feel happy that the bike was going to a good home. He did research my name on FB and knew that I knew what I was doing and that I could make it come back to life again.

The bike shows a serious oil leak, seemingly at the head gasket area, which had been drooling down the middle of the engine and onto the bottom of the crash bar. Beyond that, you could see the mufflers blowing out from corrosion, but the gas tank was super clean inside, the paint was like new and the chrome was in really great condition. And yes, there were actual new reproduction mufflers, three of which were still in their original boxes. Included were a couple of old helmets, a mint sales brochure, the owner’s manual in the tool tray, and a new in-the-package 3x5 Honda flag! As an extra bonus, the name Soichiro was applied just below the Honda tank badge.

We completed the transaction, loaded up the truck and I turned around at 2pm for the return leg back to San Diego. It had been spitting rain intermittently but the traffic was not as bad going south as it was for the late commuters going northbound on the I-15. I was very happy to have landed this great bike, even with some leaky bits that will need attention. The title was clear, registration paid to Feb 2024 and I had a good feeling that this bike might be with me for a good while.

Early or Late? How do you tell the difference between vintage Hondas?

The terms “early” and “late” are somewhat subjective and somewhat objective, depending on how you are applying the definition. Since American Honda set up shop in 1958, just about everything sold before 1960-61 would be considered “really early,” by most aficionados of the marque. Other than the first generation Honda Cubs, the CB92 and CA95 Benlys, the “big bikes” (250-305cc) were dry-sump Dreams and few of those were sold in the beginning.

"Early" CA77 305cc Dream (AHMC)

Once Honda’s production machinery really ramped up in the early 1960s, bikes came pouring off the lines in as little as every 15 seconds! That figure applies to Honda step-thru Cub models, however. Those early pushrod bikes were run continuously until about 1965, when the OHC engine designs took over. Some versions of the Honda Cub 50s (and some 90cc models) have been in continuous production since 1959, with over 100 million units produced, worldwide.

Other “early” small-bore machines were the OHV Honda 90 street and trail bikes, known as the C200 and the CT200. Again, these were superseded by OHC engines in the 1965 era.

Looking at the small twins, the 150cc Benly Touring 150s, which were also released in 1959, had a styling makeover in 1963, where the fuel tank, panels, rubbers, handlebars and mufflers were all redesigned.

Similarly, the “early” 250-305cc Dreams had their own rework sessions in late 1963, where the model changed from C(CA)77 to C(CA)78, which brought changes to the fuel tank, side panels, rubbers, tank badges, and handlebar hardware. So, the true CA77 models can be considered “early” while the CA78s are recognized as “late” versions. While these styling changes are readily apparent, that was not the end of the design process. Honda reconfigured the frame, tool tray, battery ground, battery, and side covers (and knobs) in 1966, changing the battery size/shape from the early, tall, thin battery to the wider, shorter 12N9-3A unit, also used in the CB77s.

"Late" CA77 Dream 305 
(AHMC)

Most collectors think the 1961-64 CB77s, equipped with flat handlebars, steel forks, flat seats and reverse-needle speedometer/tachometers were considered to be the classic “early versions.” In 1965, the flat handlebars gave way to low-rise units and the speedo-tach meter set mirrored the concentric CB450 Black Bomber instruments. 1966 brought alloy forks, requiring a new front fender stay design, plus the upswept seat shape, all of which carried through to the end of production. Those features are commonly referred to as “late CB77” editions.

For many Scrambler owners, the 1962-65 CL72 250cc Scramblers had the look and the sounds associated with “early” models, which included slender alloy fenders, straight exhaust pipes with no muffler can on the back and the mostly ineffective “small brake” wheels/hubs. In 1965, the CL77 was released, initially as a big bore motor transplant for the CL72. 

The fenders were changed to steel and they gradually widened to better encompass the rear wheel debris throw-off and to help keep them from cracking. The 1965 CL72 and CL77s had a “slip-on” muffler, which wrapped around the ends of the twin exhaust pipes, to better reduce the high-pitched, high-decibel exhaust notes. Those were quickly removed by the owners, forcing Honda to weld mufflers onto the later generation of exhaust systems.

By 1966, the CL77s were completely re-engineered with new alloy forks, double-leading shoe brakes, rubber-mounted rear fender, seat, exhaust, footpegs, fork ears, and a thicker chain guard. The net effect was a more beefy profile, carrying more weight and losing the slim, sleek look of the original concept. However, these “later” bikes were far more reliable and had the much-needed braking power lacking in the “early” models.

In 1965, Honda’s engineers refined the 250-305 engines, lowering the compression, changing the fin shape pattern of the cylinder heads, adding “square bowl” carburetors, and other details that held them apart from the “early” editions.

1966 brought wholesale changes to the suspension systems on many models. The “early” S90, CB160, CB77, and CL77 caught up to the CB450K0 Black Bombers by having all of their fork lowers changed from the frame-color steel style to silver-painted alloy forks. The fork style helps delineate the “early” and “late” division lines on all of those models.

In some cases, either the year or the country specification made a distinction between “early” and “late” types of handlebars. In some cases, early model Honda Sport Cubs, Super 90s and CB160s had “low bar” handlebar configurations. As production and sales increased in the US, a determination was made that the US bikes should have “Western” handlebars (read higher and wider) than the domestic and European counterparts. So, the cool little “W” shaped handlebars for the C110 Sport Cubs and Super 90s gave way to unattractive and out-of-proportion “Western” handlebar configurations, requiring whole new cable sets for each model. 

Many of the bikes with “A” (for America) designators, like CA110, CA77 and US-specification CB160s and CB77s all had “Western bar” handlebar/cable combinations. However, if the bikes came into the US before 1964, they often had the lower handlebar sets, found on non-US models. If you are restoring a 1960s model bike, exactly to as-sold specifications, then you will have to study your parts books carefully to establish which handlebars and cables are needed to make the bike correct for that year's edition.

Up to 1968, turn signals were not specified for the US market. The Honda S90 and CL90s and the CB/CL450s were a few of the carry-over machines, that came to the US without turn signals in the beginning and then had them added towards the end of production, which carried on past the 1968 cut-off date. Obviously, the turn signal/no turn signal machines are the dividing line between “early” and “late” models in Honda’s lineup for those affected by the change.

Another aspect of “late/early” models is how the bikes were affected by the change from JIS thread pitch to ISO pitches, starting with the 1968 production models. The 250-305s and 160s were out of production by the end of 1967, so are not necessarily affected. You will find some models, like the “early” CL175K0 Scramblers, which are built with two sets of fasteners, as production progressed into the 1968-beyond models.

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Mirror, Mirror on the bar, I see nothing where you are…

Honda Motor Corporation began using small rectangular mirrors on their street bikes all the way back to about 1957 on the C70-71, C75-76, and CE71 Dream Sport models. The product code on those mirrors was 250, which is the first generation 250cc Dream model. When the C92-95 Benly 125-150cc models were released, the mirror part number had a 200 code part, attributed to the Benly series machines. Honda used the 200 series mirrors on just about every 250-305cc model, plus the 125-150cc Benlys from 1959 through the 1967 production run. Because there were so many machines out in service during the 1960s, Honda continued to make the mirrors available due to demand.

Somewhere along the line, someone, for some reason, chose to supersede the 200 series mirrors to product code 041, which is for a C50 step-thru model. Obviously, the handlebar location of a 50cc step-thru is way different than that of a 250-305cc street machine. The mirror head angle on the 200 mirrors is about 15 degrees above horizontal, whereas the 041 code mirrors are a solid 45 degrees upwards. When 041 mirrors are mounted on a larger street bike, the mirror angle cannot be adjusted to be useful for the large bike rider. All you see is sky/clouds, no matter how you adjust the lever brackets on the handlebars. The only true solution is to bend the mirror heads downwards until they allow for normal viewing angles.

The mirrors all have 8mm threaded stems, which are the same diameter as the mirror stalks. This is a fairly stout chrome-plated steel rod, so they are not easily manipulated. What is required is a hefty, solid-mounted workbench vise and an appropriately large Crescent wrench (18” in this case) to make the adjustments.

If you have another person available to hold the mirror stem, keeping the lever bracket locked in place, you may be able to do this on the bike. I don’t recommend it, however. It only takes a few moments to unscrew the mirror from the bracket and secure it in a vise, once you have removed the long locking nut.

Once you have given it a good twist, check the head angle and if it is close to what you see in the photos, you should be all set to go riding with the security that you will be able to see the traffic behind you in your OEM Honda mirrors.

Thus far, the mirrors are still available from Honda warehouses, across the country and around the world. 88110-041-000 is the part number for the right mirror and 88120-041-811 will get you the left side unit.

 Bill “MrHonda” Silver  

11/7/23

Originally offered 01/2019 on the Examiner.com site (now defunct)