Rescuing a CL77 restoration… RTV is not your friend.

For some reason, the last four vintage Honda repair bikes have come from the Santa Clarita area, which is about 165 miles away. First, it was a blue CB77 with a seriously stuck engine, then a pair of bikes from the same owner: CB77 and CB550 for engine work. Now, through a relay of connections in the community, a newly acquired CL77 came down from the owner with a broken kickstarter system. The referral came from a shop in the SFO Valley, who called my friend Ed Moore in TX who called me because I was a whole lot closer to attending to the problem.

There was desperation in the owner’s voice as he had just purchased what seemed to have been a “restored” red/silver CL77 from the 1967 vintage. It had been a dream of his to own one since high school and now that he had purchased this shiny red/silver Scrambler, the dream had turned into a nightmare.

When he brought the bike to me, it appeared to have had a lot of cosmetic work done, but after a couple of starts, the kickstarter arm fell backwards and had become disconnected from the rest of the engine. Often this is a problem with either the kickstarter knuckle cracking and splitting open, so that it jumps over the splines on the kickstarter shaft, or sometimes the shaft will shear off.

With the kickstarter cover removed, the kickstarter shaft was still intact and the knuckle was not damaged. The apparent problem was that the kickstarter shaft was not engaging with the low gear via the spring-loaded kickstarter pawl. Nothing to do at that point, except extract the engine assembly and split the cases for a look. And so it began…

After draining some dirty oil contaminated with flecks of silver aluminum, the engine was pulled and hauled up onto the workbench. At about 100 lbs, lifting these things up and down from the workbench gets to be a mighty chore for my 75-year-old body. I rolled it back to remove the oil pump which allows the engine to sit flatter on the bench. Then, the clutch cover was removed to access the clutch and shifter selector parts. I could see that the engine cases had been reassembled with some kind of white RTV sealant, while the outer oil filter cover was covered in black RTV where the o-rings normally do the job. When the filter cover was extracted the shaft was jammed inside the cover because the previous mechanic hadn’t indexed the locating pin properly inside the recess made for the job.

My notes for the repair invoice included:

*Bike has extensive restoration work, but kickstarter does not engage the engine.

*Remove engine assembly and split engine cases for inspection/repairs.

*A blob of black RTV above the crankshaft indicates a misplaced crankshaft locating pin incident.

*Lower right rear engine mount bolt missing, left side finger tight.

*Engine had been opened up previously and some kind of white sealant RTV used to seal the cases.

*Kickstarter diagnosis: Kickstarter pawl retainer stop on kickstarter shaft was sheared off, allowing the pawl, pin and spring to escape their respective locations. Requires replacement of the shaft, pawl, cap, spring. Second gear had been previously replaced with one from an earlier model that has non-matching gear dogs. Replaced. 2nd M/S gear with correct type and installed offset cotter set to increase gear dog engagement. The low gear bushing is worn with the center ridge detached from the bushing body. Replaced with NOS part.

*The oil filter shaft and body were seized from improper installation. Replaced with good used, clean parts and reinstalled. Clean all remnants of RTV from engine cases and oil filter outer cover, clean oil residues from the bottom case half. Remove glued-on intake manifold insulators and install new o-rings.

Broken ear that retains the kickstarter pawl

Comparison of a broken one on the bottom and a good one on the top.

When replacing all the damaged kickstarter parts, I noted that the engine case showed a previous attempt at putting the cases together with the alternator side locating pin not indexing with the hole in the bearing. When the bearing isn’t rotated correctly, the pin gets shoved into the engine case, usually breaking out a chunk of the casting, plus the oil feed hole doesn’t match up. Honda went to a larger pin later on to prevent these kinds of mishaps, but I have seen more than a few of these engines damaged by the pin/bearing mismatch. With the cases apart, I checked to see if the bearing and pin had been realigned after the damage had occurred and the bearing alignment marks were correct. So, someone made the mistake of relocating the bearing and then back-filled the damage in the case with RTV. Because these engines don’t have a lot of oil pressure, these repaired mishaps don’t usually cause problems with oil leaks in the future.

I had a replacement kickstarter shaft along with the low gear bushing, pawl, spring and cap for the ratchet function. I noticed that there was not enough gear dog engagement for 2^nd gear, then discovered that the gear had been changed with one from an earlier version. Later gears have back-cut gear dogs that pull each other together during gear engagement, but the early ones had straight dogs that often bounce off of each other, especially when there is insufficient engagement.

I installed a pair of offset cotters, of which I have only a few left, in order to increase the engagement, after installing the correct 2^nd gear. The cotters are stamped and probably forged steel, then machined, but they are not plug-and-play, requiring some modification of the edges and ends to facilitate them sliding smoothly in the shaft track. Once everything was reassembled, the gears all stayed where they belonged and the engagement of the gear dogs was now within specs.

When the owner dropped off the bike, he mentioned that the right side carburetor slide was sticking, so his remedy was to file/sand down the chrome off the slide until it quit sticking! That’s not the path of repair that I would have chosen, but some carb body cleaning and knocking down the high spots should clear the interference problem when matched up with a replacement slide. When I examined the slide, it was obviously a left-side slide, so perhaps they were switched previously which would explain some high idle and other running issues.

I noted that there was evidence of severe varnish coatings in both intake ports, looking like they were coated with Permatex, but it was from years of sitting with old fuel solids coating the ports instead. So, that begs the question: Do I tear down the top end and clean the head/valves and piston crowns or do I start it back up again as-is, because it had been running previously?

I removed the tappet covers and inspected the valve clearances, which were all in spec. Nothing looked suspicious, but you can’t really see the condition of the cams and rocker arms without pulling the top cover off, which I noted looked like more RTV, but in fact, was axle grease! I opted to pull the top cylinder head cover off and have a look at the top-end components, plus verify that the breather plate drain holes were positioned properly. Happily, the covers came off cleanly and the condition of the cams, rockers, cam sprocket and camchain were all fresh-looking and functional.

Saturday was the engine installation day, so I gingerly eased the 100 lbs of steel and aluminum down onto my rolling cart and off we went to the awaiting chassis. I wrapped the frame tubes with rags and a towel to prevent damage to the paint as the engine was wedged back inside the frame. I use a small trolley jack to get beneath the engine to help position it for mounting bolt installations. The long bolt and spacers that go through the frame and oil pump need to be aligned just right for easy installation.

Once the engine bolts are secured, the rest of the dance includes hooking up the electrics, setting ignition timing and tacking on the tool box, air filter brackets and filters/tubes and carburetors.

Speaking of the carburetors, they were cleaned in my ultrasound machine, then the troublesome left side body was checked and the high spots removed. I had recently received a batch of used slides, including some of the later model alloy slides which seem to give a little looser fit in the carburetors. There were signs of a Keyster carb kit installation, but the original needles were still in place. The biggest issue was that the float levels had been set at 26mm instead of 22.5mm which obviously has a big bearing on engine function and performance.

I hooked up a fuel bottle and fired the engine up on the first kick! I let it run for a few minutes to check for oil leaks and any other problems, but it purred along nicely. I followed up with the air cleaners, side covers and finally the exhaust pipes. The exhaust was from a 1966 bike with the slip-on muffler, despite the 43k 1967-series serial number.

The kickstarter cover ear was broken off at the shop when they were trying to remove the cover to inspect the kickstarter issue in the beginning. This is where the inner cover is located, so there is no support for banging on the screws with an impact driver or chisel. Fortunately, I had picked up several CL engines, and several had kickstarter covers attached, so a replacement was readily available.

Towards the end, the owner mentioned replacing the headlight bulb due to a failed filament, so some electrical work was tacked onto the final repairs. The headlight bulb and rim were not grounding to the shell or speedometer as the pigtail was missing from the speedometer base. There was a mixup with the green and green/white wires, which normally creates a blown fuse situation. I wound up running a separate ground wire down to the steering damper 6mm mounting bolt to achieve the necessary ground path for the lights. The neutral and instrument lights were all blown out, so I suspect that someone had tried to run the bike with a low/dead battery and the generator went to full output and blew out the bulbs.

The bike chassis parts were eventually all re-installed and the bike was given a test run. All systems were a go with clean transmission shifts, easy starting, and all electrical systems functioning as designed. I called the owner to tell him that the bike was ready for pickup. It was just a week after he dropped it off and he was very excited to finally drive his dream bike Scrambler and enjoy it as it was originally designed by Honda.

Restoration work is fine if you are aware of the various issues that arise when you repaint and rebuild the bike from top to bottom. The chassis work was done pretty well, but the engine work left a lot to be desired and eventually remedied by MrHonda. It was fun to ride a Scrambler that had good brakes and the muffled exhaust system still had a bit of a ring to the exhaust note as it shifted through the gears and roared down the road.

It’s always a good thing when you are able to put one of these bikes back into full function to be enjoyed and admired by strangers who may have never seen/heard one before, but still recognize it as a classic machine.

Bill Silver aka MrHonda

8/23

UnFourtunate CB350F...

My friend Gilles has 15 or so various vintage bikes, mostly Hondas and he tries to keep the herd exercised regularly. He picked up a very sweet-looking Black/green 1973 machine with low miles and with stock 4:4 exhaust pipes. The overall appearance is very good with shiny chrome and bright instruments.

Factory AHMC photo

The bike exhibited the sticky front brake problems that affect so many 40+ year old original Hondas that haven’t had regular maintenance, but that isn’t a huge task to resolve. He lives up in San Diego’s N. County coast area, which is about 50 miles away from me. Fortunately, our friend Randy Troy is an excellent ace mechanic and lives out to the east of Gilles in Valley Center. Randy did the brake work and then noticed that the idle mixture screws required shutting them all the way OFF in order to idle properly. This is not a good sign and can only be remedied by carburetor removal and inspection.

I was up in N. County for my monthly chiropractor appointment, which is about 20 minutes away from Gilles, so I stopped by to have a look at the bike and agreed to bring it back home for some TLC and necessary repairs. After he bought the bike, I suggested that he pick up an electronic ignition system to eliminate the points and condenser original parts. He picked up a system from 4into1.com, which I wasn’t familiar with, but most of all of them are pretty much the same, these days. There was also a burned-out headlight bulb issue that needed to be addressed. No big deal, right?

Despite a “new battery” in the bike, Gilles has to kick start it as it wouldn’t hold a charge. I put the battery on my charger while I installed the ignition system, then tried to use the electric starter to light it off, but the voltage plunged from 12.6 to 4 under load. The kickstarter was working, but someone had taken it apart, apparently, as the mechanism wouldn’t stay retracted properly. The solution for that issue was just a 5/16” steel ball to help retain the kickstarter arm properly.

I had difficulty in setting up the ignition system as the LED light was coming on way after the TDC T mark, much less way after the F firing marks. I slotted the backing plate, filed down the protruding edges and finally got it to time correctly. The battery kept bouncing back to an indicated 12.6 volts, but there seemed to be no current available under load. The bike did fire up on the kickstarter and on a hunch I checked the charging system voltage and it was immediately pushing 15 volts at about 4k rpms. I surmised that the high voltage had popped the low-beam filament, so I shut it all down.

I ordered a new sealed beam from 4into1.com, which came in an OEM box for about $80. Going on eBay to search for the part number turned up several listings where people were asking $300 for the same part! The new bulb arrived safely and was installed with no problems. I had to think about how to rein in the voltage output, so removed the voltage regulator for inspection. There is one small adjustment that can be made to change the tension on the point set, but I could see that someone had been in there before tweaking the contact mounts and the adjustment stop. I bent the stop down ever so slightly and reinstalled the voltage regulator. Firing the bike back up on the old battery ( a new one was ordered), the voltage rose up into the 13v range and held steady. I had ordered a solid-state regulator-rectifier unit to replace the mechanical point voltage regulator, but it may not be needed.

Moving on to the carburetor problems, I extracted the carb rack from the engine and put it on the bench for inspection. I removed the idle jets and poked the holes open with my tapered reamers and then looked at the array of floats and how they were adjusted. The floats on these carbs are plastic and have a flat bottom that winds up parallel with the carburetor body bowl surfaces when the 21mm float level setting is correct. What I encountered were floats that were more like 45 degrees away from parallel and were about 31mm at the high point. Yikes! Who would do something like that and think that it was okay? After resetting all four float levels, I replaced the main jet o-rings which may have been original as they all looked pretty smashed, but were still sealing. I did a quick rinse of the bowls and put it all back together again.

With carbs mounted back on the bike, the engine fired back up (still kickstarting it) and once the mixture screws were set back out to 7/8 – 1 turn out, the engine settled down and idled smoothly once again. A test ride showed improvements in the overall power curve and throttle response, but in the end these bikes are pretty underpowered for a 350cc machine, but they do have a great visual presence and sound lovely running down the road.

With a fresh battery,  a repaired kickstarter arm, the voltage under control, a new headlight and carburetors that are set back to OEM specs, the little beauty is ready to go back home and be enjoyed along the coastal strip of San Diego’s N. County beaches.

Bill Silver aka MrHonda

8/16/23

PS

No good deed goes unpunished….

After delivery to Gilles, where we met about halfway between his home and mine, he rode off to cruise the coastal highway only to have the electronic ignition die about 10 miles up the road. I was almost all the way back to my home and had to U-turn and pick up the bike again. Fortunately, the bike died about a quarter mile away from where his wife had stopped to grab lunch, so she took him back home. I ordered a tried and true Dyna ignition kit from 4into1.com and that should solve that problem.

There were signs of an oil leak as well when the bike was parked. Removing the left side sprocket cover revealed a little bit of a leak coming from the threads of the oil pressure switch. That was remedied with some Teflon tape and solved the little oil leak problem.

While it was here, we decided to do an oil and filter change. There was a bit of weeping at the drain plug, so I installed a new one with a fresh, new aluminum gasket. The final check ride showed a dry motor on the bottom, instant starting even without the choke and a nice smooth ride again. It could use some quality rear shocks and a little front fork work to smooth out the ride quality, but it is what it is, as it was from the factory 50 years ago.  

Cute little baby Chopper with a mysterious secret…

I happened upon a posting for a 1979 CM185 TwinStar bike for sale just about 10 miles away. In FB chat messages the owner, a young 20-something woman, was going through a move and divorce and needed to move the bike along to a new home. The photos made the bike look well-cared for and complete, but the conversation about the details revealed that the ex-husband had tossed out the side covers, original carburetor, and license plate. Nice guy!

                                                          OEM FACTORY PHOTO

The bike was purchased a couple of years before, but the funds to get it going again were low, so it sat quietly. She did have the original CA title showing the miles at 3100 and mentioned that the tires had been replaced just before purchase. The date codes on the tires were xx21 so that verified the information. The battery had been purchased then but was now a few years old and not very high on voltage. These early bikes only had a 6-volt electrical system and a 4-speed transmission. They rolled on 17” tires and came with some seriously high 6-bend handlebars from the factory.

https://magazine.cycleworld.com/article/1977/11/1/honda-cm185t highlights the introduction of the model.

The engine is based upon an original 125cc twin. I owned an early CB125T, which is a totally different animal with a 180-firing crankshaft, a tachometer that redlined at 12,000 rpms and had dual carbs, a 5- speed transmission, and 18” wheels, with a front disc brake. Plus, it had a 12-volt electrical system.That bike would go 80 mph right out of the box.

Unfortunately, Honda chose to de-content the CM series versions with no tachometer, a single carburetor, 4-speed transmission, small 17” wheels, uncomfortable stepped seat, a side stand only, plus the silly high handlebars. It was designed as an entry-level machine at a low price. The next version of the bike was enlarged to 200cc and acquired a 12-volt electrical system. After that the bike grew to become a CM250, then the CB250 Nighthawk and the ubiquitous 250 Rebel, all with the same engine platform

The engines split vertically with the center crankshaft bearing wrapped with a cast-iron holder that bolts the crankshaft firmly into the engine case half. The camshaft chain is a Morse-Hy-Vo linked chain and the whole powerplant is robustly designed for a long lifespan.

The bike’s original carburetor was no doubt full of old gunk but probably rebuildable. Unfortunately, the choice had been to install a cheap Chinese knock-off copy, of which there are many still listed on eBay as fitting the bikes, but they all lack the angled throttle cable guide that is part of the carburetor top. The cable winds up having to do a 90-degree bend, outside of the cable adjuster. There is a part number for the carb top, but the eBay pricing is in the $50-60 range, despite the fact that CMSNL shows them at $22. After trying an OEM carb top, it turns out that the Chinese copy carburetor has a 22mm slide vs. the 20mm slide of the stock carburetor.

I met with the owner, looked over the title situation and the condition of the bike and we made a deal that reflected the missing parts and the non-running condition. During inspection, I was amazed to open the gas cap and find a perfectly clean tank surface on the inside! That seldom happens when I go to look at almost any used bike now. The bike had been stored mostly indoors and the paint on the fuel tank was still in its lovely red condition. There was pitting on a lot of the chrome parts, but the worst was on the turn signal stalks. Too bad about the missing side covers, which seem to have a “value” of around $75+ each now. She helped me push the bike up into the Tacoma and off I went back home with this little cutie, not knowing that there were some interesting challenges ahead.

The first thing was to put the battery on a charger and see about getting the static voltage value above 6 volts. In the meantime, I extracted the carburetor and noticed that the large heat shield insulator had been cut off at the bottom. The insulator was designed to prevent engine heat from being transferred directly to the float bowl. While the remaining portion still insulated the carburetor flange from the cylinder head heat, the cut-off portion would allow more heat to warm the float bowl contents. More things to go hunting for on eBay and elsewhere.

So, the carburetor had a little bit of green slime inside, but nothing drastic. I cleaned the pilot jet, and main jet holder cross-drilled holes and checked the float level setting. It all looked close to OEM settings, although the main jet had no size marked on it. It was reassembled and reinstalled with hopes of the bike firing up once the battery was charged up some. The main jet was not marked, but according to the Honda tune-up book, the main jet was supposed to be a 105 and the one that came with the carburetor was more like a 100, so an OEM jet was installed.

With the battery installed into the bike and the carburetor fuel system secured, I turned the key on and kickstarted the engine over…. and over and over. It started to sputter once, then died, and then went dead. I pulled the battery out for more charging and then removed the point cover on the left end of the crankcase to access the points. When I flashed the points with spark plugs in place, I got a meager tiny spark that was intermittent. I checked the spark plug caps and both seemed to be infinitely open according to my ohm meter. I rounded up some spare known good plug caps and picked up a set of plugs from O’Reilly auto parts, but the only options for these bikes are CR7-HS vs. the original C7-HS spark plugs. So, with resistor plugs and resistor caps, I was concerned that the spark intensity might be diminished.

I removed the point plate to better clean the point faces. I noticed quite a bit of arcing wear on the faces, which sometimes indicates a weak condenser. What I noticed was that the point arm, which is a phenolic material had a brass insert for the pivot function. For some reason, the points seemed to hang up before closing, due to some kind of roughness or wear in the pivot area. I dismantled the the point am and checked for areas of concern. There were two little wave washers on top of the point arm that seemed like they might be causing some extra pressure on the pivot point, so left one off. With that done, the points seemed to pivot more freely. What had happened previously, was that the engine would fire for a second then quit. When I checked the point's timing with a test light, the light would stay ON all the time, which usually indicates some kind of point face corrosion or dirt, but these were nice and shiny. After putting the point plate back on and going back through the carburetor one more time, the engine fired up and kept running even with the wobbly battery condition.

These bikes have auto-on headlights, so I removed it to lessen the current draw on the system while trying to get this thing to run. I must have kicked it fifty times expecting it to light up previously. What had been presumed to be a problem with the carburetor turned out to be a problem with the point set function instead!

I drove it up to the local 7-11 for a gallon of gas and rode it carefully around the neighborhood shifting through the gears and testing the brakes. There seems to be some chain snatch or perhaps an abrupt transition from idle to part throttle on the carburetor, but overall it was quiet and ran like it should. Even all the lights were working. The plastic tail light base had stripped-out holes, so a replacement unit was ordered from 4into1.com for a reasonable price.

You always feel relieved when your “bought-dead” bike comes back to life without any huge issues to remedy. New fork seals are on order, along with a new battery and a carb top with the correct angled cable receiver which should fit the carburetor. I have often had a small bike or scooter available to use to haul small packages down to the post office in Bonita, CA which is just a couple of miles away. Looks like this might be just the ticket to take the place of the last PO runner machine at a low price.

Follow-up repairs

The fork seals were replaced, and a new battery was installed which offered instant electric starting, but there was still a persistent oil leak coming from the left side. The shift shaft seal was replaced and finally, the countershaft seal, which looked pretty good when removed was also replaced. The engine case doesn’t have a stop machined in for the seal so in driving it into the recess it kept going in another 1/4”. I decided to install the second seal in tandem with the first one and now there are no leaks. I did drain the dark oil which had some aluminum swirling around and smelled somewhat like gasoline, so now it has a fresh 1.6 qts of Honda’s finest GN4 oil. The 4into1 rear tail light was installed, but the original screws and setting collars left the light assembly dangling. I peeled off the rubber cushion from the back of the original tail light and that provided the additional thickness to mount the light assembly correctly.

DrATV supplied some non-resistor spark plug caps and I purchased a backup set of points and condenser in case the originals start acting up again. So far, since these final repairs, the engine is oil-tight and the spark plugs are coming out clean. The engine seems to run up to whatever redline is without any signs of overheating. In checking the specifications in the Honda tune-up book, it appears that the upgrade from the CM185 to the CM200 included a camshaft change and carburetor change. The 185 camshaft shows 0/30 and 30/0 cam timing, whereas the 200 version is 7/27 and 27/7 specifications. Theoretically, this should give the engine a boost, although probably marginal given the whole design.

Other than searching for a set of nice red side covers that are less than $160 a pair, the bike is as good as it is going to be. A luggage rack would be handy for my eBay package run to the local post office, which is just a couple of miles away. This will take some of the unnecessary wear from my Tacoma, as the air-cooled engine heats up quickly and won’t sustain the kind of cold-start oil contamination of a water-cooled engine for short hauls.

The bike has a happy spot at about 45 miles per hour. The top speed is around 70 mph, but it gets really busy sounding as it strains to make enough power to move itself and my 200 lbs down the road at speed. It definitely has no place on the SoCal highways at all.

So, basically, for about $1,000 I have a fully licensed and registered, little runaround-town bike that is light and economical for local trips. These were certainly not on my wanted bike list, but sometimes an opportunity to buy something with promise and utility is too good to pass up.

Bill Silver

aka MrHonda

08/2

Double or nothing… CB77 and CB550 Part 2

The next day…the next bike.

So, while I was waiting for parts from Germany and the UK, I removed the carburetors from the CB77. The left side looked normal with old fuel solids and a clean intake port. The right side carb was full of water corrosion and scale, as was the whole intake port. This was certainly a good reason for a seized engine condition.

I slid a little jack under the oil pump drain bolt and removed the engine mount bolts and disconnected the electrical connections. I use the little wooden Harbor Freight dollies to move the engines around the shop and to work on the engines for disassembly. The cylinder head came off easily as the master link for the cam chain was just below the top cover surface.

Sliding the head off of the studs allowed a big splash of penetrating oil that had been used in an effort to soften up the offending water and rust build-up inside the cylinder. The pistons were nearly even in the bores, about half-way down the cylinders. This allowed the cylinders and pistons to be raised up in order to allow use of an air hammer to try to drive down the affected piston.

I’m sure my neighbors didn’t appreciate 20 minutes of nearly continuous air-hammer operation as the piston very slowly moved downwards in the affected cylinder. By the time it got to the bottom, the liner had cracked, but at least the piston was free of the cylinders and the rest of the disassembly could continue.

Based upon the worn counter-shaft sprocket teeth, the engine and bike probably have 20k miles, but with the replacement NOS speedometer, there is no verification of what actual miles are on the whole bike. The clutch side components were disassembled, in surprisingly good condition apart from a very stretched-out primary chain. The little thrust washer for the oil filter had been installed on the inside of the filter body, incorrectly.

Splitting the cases revealed some interesting features. The gear dog engagement was well within specs and most surprisingly the low gear bushing had a nice sharp edges ridge in the center and was still a good fit into the low gear opening. Even the kickstarter pawl was not deeply worn down. But in cleaning off the top gear/output shaft, the whole internal bushing just slid out. That was a first-time discovery for me. I had a spare gear with the correct back-cut gear dogs, so it was put into service after cleaning up. The shift drum and forks showed minimal wear, so the cases were reassembled.

The cylinder head was the next job. I tried using some oven cleaner to strip off 50 years of grease and corrosion, which did a pretty good job but left some traces of a chemical reaction in the metal surfaces. The head was disassembled and the packed-on goo from the penetrating oil and old rust was removed. The valves didn’t appear to have a lot of carbon buildup, so someone had probably been into the engine once before, at least the top end. All of the lower-end fasteners were obviously not disturbed in the past, so it was still a puzzle how the transmission parts were still in such good shape. Apart from the usual layer of grit and oil solids in the bottom case, the transmission gears all looked pretty clean, so it must have gotten regular oil changes in the past.

Looking through the stack of heads and cylinders that I had purchased from Tim in Ventura, I found a die-cast, late-model set of cylinders with a nice camchain tensioner. The cylinder bores looked like they had been machined and not reused. It turned out that they were on. .25 oversize and cleaned up fine with my large hone. The next trick was to find .25 pistons and rings at a reasonable price. Fortunately, I called my friend Ed Moore, who has been rebuilding these engines for many years, and he came up with some .25 pistons, but no rings. We made a deal on the piston set and I found an almost reasonable set of new OEM rings for $75.

I removed the valves from the cylinder head and cleaned them on a bench grinder wire wheel. They had somewhat wide seats, but for this engine, they would be fully serviceable. Lapping in the valves to the seats yielded good results, so the rest of the head was assembled with just some concerns about the cam sprocket return springs. I purchased new springs from Tim McDowell, but they still didn’t quite take up all the slack in the advancer return weights. With this little amount of free-play, the spark timing will advance slightly when the engine is idling, which isn’t necessarily a bad thing. Stock ignition timing is 5 degrees before TDC and these engines prefer to idle more like 10 degrees before TDC. On a somewhat budget-restricted engine build like this, some compromises are going to be made.

The aftermarket pistons from SK consistently come with piston pin bores that are slightly too tight, so pins cannot be easily pressed into the pistons. I have a 15mm ball hone that will take out just a bit of material enough to make the pin fit normally. These pistons have a Dream-style piston crown. The machining appears to create a lower piston profile than that of regular CB pistons, but in practice, they tend to increase the compression readings when installed.

The oil filter was in need of cleaning, of course, and the oil pump screen was still usable after the gaskets were pared away from the screen flange. New gaskets and seals, plus a screw kit and the return springs all came from Tim McDowell’s site: www.classichondarestoration.com, and arrived in just a couple of days.

To remedy the water-damaged carburetor, I was able to pull out a good spare carb body from the extras that came down with the bike, so that issue was remedied without extra expense.

The replacement cylinder block for the engine was a die-cast unit that uses the narrow tensioner. I was happy to have a ready-to-go cylinder except for the broken fins on the top and in the middle of the cylinder block. Rob North managed to squeeze me into his work schedule and fix the fins so I could wrap up the engine work.

Dave had asked me if there was a problem with the starter motor. I seldom see problems with them, so I cleaned it up and added a little silver paint to freshen it up. Once the engine was finalized and re-installed, the starter button only brought forth a “click” and then nothing more. The tags on the bike were from 1977, so I thought that the solenoid might have had corrosion buildup on the internal contacts. Removed and disassembled, the solenoid really wasn’t having issues, it appeared. So, once I knew that the battery power was getting to the starter motor, I knew that the starter had to come back out for inspection. 

Taking the wrap-around cover off the brush end of the starter revealed a stuck contact brush in the holder, but no signs of corrosion that would cause such a problem. I cleaned the brush holder carefully, but every time the brush was inserted, it would jam up again. Finally, I carefully filed a little material off of the sides of the brush until it slid easily through the holder.

I had already replaced the starter clutch rollers, springs, and caps, so that wouldn’t be an issue, but once the starter was replaced, the motor would try to pull the engine over with the starter chain, but it would stall out and make a loud screeching sound. The last place to visit was the starter drive end, so the motor was removed yet again and the drive removed. The three screws that held the drive unit were not factory tight, so someone must have been wrestling with this problem previously. There wasn’t a lot of grease inside the planetary gears and sun gear, and most of it was dried out. Cleaning the sun gear, I discovered a groove in the outside of the piece that clicked in an old memory of having these starters apart before and that there was supposed to be a steel pin that anchored the sun gear to the housing. All I was able to find was some tiny pieces of pin, buried in the old grease.

I searched through my bits and pieces of Honda parts and didn’t find anything that was that small. Finally, I discovered a 1/16” drill bit that fits the housing hole just about right. I shortened up the bit so that just the smooth shank was a nice fit and reassembled the drive unit with fresh grease. Finally, the starter motor kicked the engine over with vigor and it started up quickly. I was feeding the carbs off of a remote fuel bottle and let it idle for a few minutes while I checked for oil leaks or other issues. There was no smoke out of the header pipes and no leaks so it was good to go, as far as I could see.

As always, there were side issues that took more time and running around to solve. The ignition switch which had a common T series key started to seize up during the first few minutes of getting powered up after 45 years. I took it out, noticing that a few wires were not installed correctly on the back. On top of that, the whole wiring harness was installed over the frame tube instead of beneath it back by the battery box. So, more time was taken to cut through all of the tie-wraps and reposition everything. Inside the headlight shell, the speedometer bulb covers had melted in place, so the whole speedo was removed and the rubber chipped off of the bulb sockets, which were empty when removed. New bulbs were installed and a newer light bulb harness was installed. The neutral light lead was missing as well, plus there was no headlight rim. There was a new bulb in the box of spares, so I offered up my last NOS headlight rim and clips to put the headlight back to normal again. The bike had huge 6-bend handlebars, so the starter wire had been extended to connect to the harness leads. The dimmer switch was found in the box of spares, with a partially set of extended wires that were never completed. Bikes like this will drive you crazy with all the little detail issues that need five or ten or fifteen minutes or more to resolve, not including finding the necessary parts to put it all together again.

Dave came down a few days later, on a Saturday morning, leaving his house at 4am. He arrived in Spring Valley at 7:30 and after some test running of both bikes, they were eventually loaded up on his 3-rail trailer, and off he went back to Santa Clarita. He was pleased that I was able to revive these two neglected bikes and has plans to get them fully cleaned up and licensed for the street.

It was a huge undertaking for me, especially having stuck piston pins and pistons in the two bikes. I was happy to get a final check for the work and parts, then send both bikes off to new lives in Santa Clarita (actually Canyon Country, according to the ZIP code).

Bill Silver aka MrHonda

08.01.23

Double or nothing… CB77 and CB550 Part 1

My friend, Dave, who lives 165 miles away in Santa Clarita, CA sold a rough, but mostly complete CB77 a couple of years ago. The engine was severely seized and it took drastic measures to get it apart and rebuilt. Eventually, it did run again and was sold during the pandemic.

Fast forward 2 years: Dave calls to say that he found a “red” CB77 that had belonged to a Honda service manager that had been sitting on a patio for 7 years. Dave bought it and brought it home for some cosmetic cleaning and sent photos. The bike was a 1965 series chassis/engine, but had a pre-64 front brake panel and a NOS early style speedo-tach installed. The whole front fork assembly had been chrome-plated at some point in time, giving the bike a unique almost chopper-style look, but the forks were not extended. The tank and fenders were painted red, but the chassis was black.

Dave’s other “project,” that he was anxious to get running was a 1974 CB550K model, which he bought cheap due to a seized engine. The speedometer showed about 15k miles and so he had a local mechanic disassemble the top end to gauge the damage. The mechanic covered the pistons with a cloth rag, covered it all with clear shipping tape to keep out the dust/bugs and Dave put it in his shed.. for about 3 years.

Dave proposed one of two scenarios… Fix the CB550 to get it running and he would give me the CB77 OR…. Fix the CB550 and the CB77 and he would pay me for both repairs.

At the time, a motorcycle wrangler, who is located in Ventura, CA (200 miles from me) had offered 3 Honda 305 bottom-end engines, plus a stack of heads and cylinders for $305. Ventura is 45 minutes away from Santa Clarita, so I reluctantly decided to make the journey in my 2015 Tacoma and fetch as much as possible.

The trip to Ventura took 4 hours on a somewhat light traffic Tuesday morning, starting from San Diego. I met Tim, the owner at a dusty, warehouse in Ventura, next to a couple of Harley repair shops. He opened the sliding door on the alley and we went inside to survey his pile of misc bikes and parts. When he posted the photos of the engines, one caught my eye, as it appeared to have a crankshaft-mounted magneto ignition system in place of the stator/rotor. That motor was a CL72 and he had the matching frame in a pile of other CL frames. At first, he was going to keep the CL72 package and replace it with one other CL77 bottom end, but then relented and threw in the CL72 engine and frame, as we were not able to extract the magneto with hand tools that I brought.

This load pretty much filled the space behind my seat on the X-tra Cab Tacoma, plus half of the bed. I called Dave and told him that I would have to drop off the engines when I picked up his bikes, then he could bring all of that down when he came for one or both of the bikes. At Dave’s, we loaded the two bikes and associated parts, which filled up the bed, so Dave stashed the 305 parts in his shed where the bikes had been sleeping. Off I went on the return trip to San Diego, leaving at 4pm, heading into afternoon rush hour LA traffic. My WAZE GPS app on the phone took me on and off the freeway, down side streets, back on different freeways, and eventually on the rest of the I-5 southbound traffic. Another 4.5 hours later and 459 miles, the Tacoma came to rest back home again. I just left everything in the truck, backed into the driveway, and called it a day.

On Wednesday morning, I unloaded the truck and sorted through boxes of parts that were removed from the CB550. The cylinder head and cylinder block still had remnants of the factory head gasket material which was fused to the mating surfaces. When the rags were removed from the pistons on the crankcase, all four were seized to the rods and wouldn’t even rock back and forth on the wrist pins. Ugh! Flooding the pistons and pins with PB Blaster, I used giant Channel-Lock pliers to rotate the pistons on the pins, slowly loosening them up. Sitting in the shed for 3 years in a location that had temperatures ranging from freezing to 115 degrees, the air inside the engine cases, condensed moisture inside the pistons and it ran into the small oiling holes in the top of the rods, causing rust to form between the pin and rod end. BTW the last license tags on the plate were 1982!

                                              Four pistons, frozen in time. Wrist pins rusted to the rods.

Just digging out the wrist pin clips was a chore as the moisture had caused corrosion between the steel clip and the alloy piston. Eventually, I was able to extract a clip from the #1 piston. I have a heavy-duty piston pin pusher tool that I bought from a man who was selling Benelli parts at a time when I had bought a Benelli Sei, 6-cylinder 750 bike. The tool had a shoulder for a 15mm pin but the end was tapered down so that it fit into a 14mm pin on the CB550 rod. Using the tool, with the help of a CB77 fork tube on the handle, I was able to force out one pin at a time, until all four pistons were removed. This was a one-hour process of very physical work, but at least they were free from the engine, to be replaced by some inexpensive piston kits from David Silver Spares. The cylinders had some staining on the walls, but were not heavily corroded, so a hone job and fresh STD pistons should remedy the top-end issues.

Cleaning off the base gasket material and then the head gasket leftovers from the head and cylinder took 3 hours of concentrated scraping, one little piece at a time, until it was gone. The original gaskets were probably asbestos and Honda added some kind of adhesive to the head gasket to prevent the persistent oil leaks that plagued Honda fours for many years. Once the engine was heated up and running, the gaskets were fused to the cylinder head and cylinders, making removal very difficult.

The head was disassembled and all the valves cleaned, seats lapped, and stem seals replaced. Top-end gasket sets are available from the aftermarket but I have had several poorly made gasket sets that didn’t even line up the bolt holes, so I searched for an OEM gasket set. These are in short supply as well, plus Honda did offer some non-asbestos kits with an -S01 suffix, but the only one I could find was in Germany on eBay. It took about 10 days to get to me.

More bits came from 4into1.com to complete the engine work, but the last task will be the carburetors, which are not easily disassembled and cleaned, plus the OEM gasket kits are about $40 each. Most of the aftermarket carb kits are from Keyster and they don’t have a good reputation for accuracy in the calibration of jets and slide needles. Whenever possible, reusing the original OEM carb hard parts is best, with the use of the a/m kits for the soft parts and float valves.

I tackled the carbs while waiting for pistons and gaskets from the UK and Germany, respectively. The #4 carburetor had water damage and the emulsion tube was heavily corroded and plugged up. The carbs had to come apart to change the fuel feed T-fitting o-rings, so you have to play watchmaker to tease everything apart, not lose all the little spring-loaded components and eventually, reassemble it all again. I spent over 3 hours in the disassembly, treating the single carb body to a little phosphoric acid bath and then replacing the o-rings. The carbs just fit into the Harbor Freight home-sized ultrasonic cleaner and the combination of Pine-Sol and water did a decent job of cleaning surfaces and passages. All of the steel parts of the linkages had some rust and corrosion, so you just have to take your time in the reassembly process.

There will be at least ten hours of labor involved, just with the CB550 engine repairs. The CB77 engine is frozen, of course, so the fate of that bike is yet to be determined.  

End of Part 1.       

Bill Silver aka MrHonda