Score four and many more to go… last installment!

A little backtracking here, to catch up with the final repair experiences and eventual sale of all four bikes!

1965 CB77 Notes

While it looked relatively intact and came with a set of correct type mufflers, this bike obviously sat around for many years and had numerous surprises in store for me.

The first thing to do was to try to remove the seat…. It wouldn’t come off even though the rear seat bolts were not installed… ???  When I grabbed the right edge and lifted, the seat pivoted up on some home-made seat hinges, just like those on the later CB350-450s!  Well, that’s really different!

With the seat up on the side, the fuel tank was removed after cutting the fuel lines with clippers. There were no air filters or tubes present, so I stuffed some plastic bags/rags into the intake ports and rolled the bike over to the front yard gravel bed where it was soaked with S100 cleaner and hosed off. Some compressed air dried off the chassis and work went on from there.

The dipstick had dirty looking oil on the stick so an oil change was in order. I removed the bolt but NOTHING came out! Probably not a good sign, is it?  The clutch lever was a two handed effort to move even slightly, so the first place to go was the clutch cover. Once removed, some oil started to trickle out however.  On a hunch, I pulled the whole oil pump and a quart and a half of stinky old oil rushed out of the crankcases. Looking at the oil pump screen and drain plug, there was a thick layer of gooey black gunk covering the parts enough to actually block the oil from draining out of the drain hole! ICK! The insides of the crankcases, behind the clutch assembly were scaly black like old gasoline and oil had evaporated on the surfaces. I lifted the oil filter and chain off of the engine and was dismayed to find that the crankshaft nut was never fully tightened (plus the conical washer was on backwards), so the filter chain sprocket was just spinning easily and not driving the filter at all. At least someone had taken time to bend the locking tab over so the nut didn’t fly off the end of the crankshaft!

The clutch plates peeled off without too much trouble. Everything was washed with paint thinner and the steel plates run on a wire wheel to scrub up the surfaces. Everything went back together without issues, but special attention was given to the locking nut and washer/sprocket placement. With the cover back on and the oil pump scrubbed up, the pump was reinstalled. A ½ quart of Marvel Mystery oil was added to the crankcase, followed by a quart of Honda GN4 10-30 oil in hopes of dissolving the sludge inside the engine.

The carbs were removed and cleaned, but there was evidence of water getting into the left side carburetor at some time. When the carbs were removed, there were a lot of chalky deposits found inside the intake port on the left side. There wasn’t any sign of water/rust on the old spark plugs, so one has to imagine that the intake valve was closed when the water backed up into the port. Use of some penetrating oil called ACF50 seemed to dissolve the deposits in the port and I could push my finger all the way down to the back side of the intake valve to help clean things up. Still it is a pretty sketchy proposition as often the back side of the intake valve will have a rust buildup on the back side that will eventually get sucked into the cylinder when the engine is running. Initial compression readings were 150 psi on the right and only 90 on the left side.

Phosphoric acid was used on the float bowl and a few other parts to neutralize the scale deposits and the carbs were checked over and reassembled with new o-rings on the carb flanges and the insulators. The petcock was cleaned out and showed signs of perhaps being a NOS part due to some very shiny surfaces inside. The carburetors were also in very good shape with no wear on the chromed brass slides whatsoever. Carbs and petcock were installed back on the bike and a fresh battery inserted into the frame holder.

There was a fuel leak on the left carburetor that seemed to be due to a compressed float bowl gasket and not enough tension on the bale spring. A new bowl gasket was slipped in place on top of the old, glued-in version and the leak stopped. With full choke ON the starter button did nothing when depressed. Looking at the overall condition of the bike, I surmised that the electrical contacts were probably all fuzzy and corroded, but cycling the starter button a few times began to wake something up. At first it was just a click, then the sounds of the starter motor engaging briefly. Continuing to push the button finally created a complete circuit and the engine spun over vigorously and finally fired off on both cylinders!

Letting it run for a few minutes at low engine speeds, I listened for any signs of damage or impending seizure due to a lack of oil, based upon what I saw draining out previously. The engine seemed to be fairly healthy and after some initial smoking the exhaust cleared up completely. Pulling the spark plugs there were no signs of any engine distress or ingesting anything damaging. Compression readings rose to 120 on the low side, which was promising to say the least.

I had already replaced the apparently original stock OEM front tire and the silly 3.50x18 Trials tire on the back with correct sized Michelins. The clutch cable was replaced along with the worn out clutch adjuster which brought a reasonable lever pull effort back into play. The front brake cable came from old stock, so the main control cables were now functioning properly.

I took it for a brief test ride and didn’t notice anything amiss, so gradually lengthened the ride time and distance out further. The bike had come with some aftermarket shorty mufflers, but the deal included some OEM type mufflers which were installed. The right side was an old Dixie International “Superior” CB77 copy which didn’t fit quite right but looked the part. The left side muffler was an OEM 2 piece muffler which was in good shape apart from some battery acid stains on the inside. There were no baffles in either one, but the overall sound was tolerable for the neighborhood.

After a couple of rides, I checked the oil and the end of the dipstick was BLACK! I warmed it up once more and then dumped the oil out of the drain hole successfully. The Marvel Mystery oil was definitely doing its job so far, but I refilled the crankcases with straight Honda oil this time.

This is a later 1965 bike with alloy forks and low riser handlebars, which is surprisingly comfortable and the bike is better than it looks overall. Gear shifting was a bit cranky sometimes, but it did go into all 4 gears without much effort and the clutch is working great now!

1967 CL77 notes

This bike is an enigma as it only shows less than 1600 miles on the speedometer and is complete and original apart from some tires that were swapped onto it many years ago. The seller swore that it ran great when he had it running, but that was about 5 years ago.  A fresh battery awaits this poor machine, which suffers from a lot of chrome corrosion on the fenders, tail light bracket and fender stays.

Once the battery was installed, the carbs cleaned and new air filters installed, the bike was a good runner, but still looked very sad with extensively corroded chrome plating everywhere on the bike.

September wrap-up

SOLD!  1966 CL77 to a Mid-West enthusiast who already owns and has restored 450 motorcycles! Sale came at the VJMC West Coast Rally in mid-Sept.

SOLD! 1966 CB77 to a local friend in his 60s, who is actually re-learning to ride a motorcycle, after taking the safety classes. He wanted a Super Hawk, but not too good of one to ride around town and have to worry about dropping it and damaging a high-dollar show bike.

SOLD! 1965 CL77 to a buyer who came all the way down from Watsonville, CA! His late arrival on a Sunday conflicted with  my plans to attend the annual DGR ride here in San Diego, which I had to forgo in order to facilitate the sale of the Scrambler.

SOLD! 1969 CL175K0 to a buyer who came down from the Ontario, CA area in a 1977 Toyota PU truck. The little Scrambler gave me fits at the end, having to R&R the engine 3 times to overcome a camchain snagging issue that kept popping the master links apart. It ran well after all the work was completed, but the wide-open throttle stumble left me baffled and I never fully figured out what was happening with it. Sold cheap, so new owner can play with it and sort out whatever was happening, I guess.

Score four and many more to go… Cont.

CL77 notes

Looking like the most promising of the four bikes, the 1966 CL77 showed only 3600 miles on the odometer and the whole chassis had been powdercoated in an earlier restoration effort. The fuel tank was clean and a rebuilt petcock was installed, along with a new battery. The battery was the first challenge to surmount, as the battery terminals on the CL harness have installed nuts on the connectors that are not a match for the posts on the new batteries. Eventually, a Dremel cutoff wheel was used to saw through the outside edges of the battery posts and a little redrilling of the holes allowed the battery hardware to finally connect up. With power ON the horn worked, as did the other electrical components which were still attached. There was power to the ignition system, so from that point the rest would be regular tune-up adjustments…. Or so I thought.

The carburetors had shiny air/speed screws installed indicating carb kit repairs. When the float bowls were dropped down, a thin layer of oil gasoline deposits were found in the bottoms. The main jets holders were removed and the idle jets coaxed out of the carb bodies, which can be difficult on a CL series machine with the exhaust pipes in place. The main jets were poorly stamped, but I was able to make out that they were #130 sizes, which is about right for a 305 Scrambler. The idle jets seemed to be open as I could see light through them, but when I pushed the jet cleaner wire into the jet, it wouldn’t go! I tried going in from both sides, but still no luck. Grabbing a magnifying glass I was able to make out the number 30 barely stamped into the jet faces. WHAT??????  I have NEVER seen a #30 idle jet applied to any Honda motorcycle engine, no matter how small it was. Ah, the joys of aftermarket jet kits!!! I dug out a pair of #38 jets from spares boxes and installed everything back into the awaiting carburetor bodies, still hanging off the back of the cylinder head.

The ignition timing was next and the first thing that was noticed was that the points were ND style but not ND branded parts. I have had bad luck with these parts in the past, as they often don’t allow a good gap and proper timing within the limits of the point plate slots. The gap on the right side was barely perceptible when opening. After contact cleaning, the left side was set to .014” and timing plate adjusted so they just opened at the LF mark. The right side gap was carefully adjusted until they just opened at the F mark AND had a decent point gap setting.

I dropped the fuel tank on the frame, cut some new fuel hoses and went to fill the tank with gasoline. I thought it was ready to receive fuel, but I had overlooked the fact that the fuel tank was a late model replacement tank with NO crossover tube and that the petcock still had the crossover tube fitting in place… open to atmosphere! As I poured gas in it flooded out over the motor until I finally figured out what had happened. With one hand I was able to plug the fitting and with the other hand cut a piece of fuel hose and stick a 6mm screw into the end to make a block-off plug. I slipped it over the petcock fitting and mopped up the fuel overflow on then engine and off the floor. The bike doesn’t have any air filters or connecting tubes so any kind of a back fire would have lit it up into a ball of fire.

I did check compression readings on this engine which were 180 psi on both sides, so this should be a healthy motor. With just a couple of kicks, the engine fired up and smoothed out quickly. With the stock OEM muffler system in place, the bike is relatively quiet, but the whole package is not without its own set of harmonic tones.

I put the seat on loosely, turned the bike down the driveway and pulled in the clutch to engine 1^st gear. I could feel it jerk into gear because the clutch plates were “stuck” from sitting, however with the clutch lever held in and a few engine revs applied the clutch disengaged and worked somewhat normally again. I ran it down the street checking the gearbox and then rolled it back up the driveway to rest for awhile. This one turned out to be better than expected so far. Hopefully, someone will adopt it before more work needed is done by me.

Score four and many more to go…

Just when I was getting a few less bikes in the driveway, my friend Burt forwarded a Craigslist posting that showed many, many Honda motorcycles up for sale. The owner was cutting down his collection of about 100 machines, mostly 1960-70s models. His aim was to focus on SOHC Honda CB750s and he had managed to acquire a rare sandcast CB750, although the engine was stuck when he bought it and the bike was a definite candidate for a full restoration.

The trip to Riverside, CA took about 2 hours, as we went north out of San Diego during the late morning hours. As advertised, the seller had a LOT of bikes, but a fair selection had been left out in the open, covered loosely by tarps. It took awhile to get to know him and see the collection of bikes and parts that were covering steel racks around the edges of his large workshop space. He had 3 bike lifts in place, all supporting various project bikes, including a C110, CB750K0 and something else I don’t recall.

Most all of the bikes were projects and eventually we came to an agreement to purchase four bikes: 1966 CB77, 1966 CL77, 1967 CL77 and a scruffy CL175K0 Scrambler with a stuck engine. The CB77 was pretty complete, but had shorty mufflers attached. There was a set of CB77 mufflers found on a rack, which were included in the deal so that made it more palatable.

Burt had followed me up with his Nissan Frontier pickup, so we were able to put two bikes in his truck and a pair in my 2002 Tacoma. The time spent at the seller’s house, plus a stop for a late lunch put us back on the highway moving into rush hour, so eventually the return trip ran past three hours before the bikes were unloaded.

CL175K0 notes

I brought the 1966 CL77 and the CL175K0 home for immediate care. The little 175 Scrambler was seriously seized and very rusty on most all of the metal surfaces. The bike had Oregon title/plates and looked like it had been sitting in the moist elements of the Pacific NW for many years.  I extracted the engine, pulled the head and coaxed out a seized left side piston, which loosened the cylinder liner in the process. The piston rings were all stuck and/or cracked-broken in the ring lands, but the engine seemed to be in the kind of condition that verified the 3600 miles showing on the speedometer.

The cylinders were still on STD sized bores; so a pair of pistons and rings was acquired from David Silver Spares, along with seals, gaskets and carb kits for the power-jet 20mm Kei’hin still attached to the original, decaying air filters. DSS had a new wiring harness and headlight shell for a reasonable price, so those were put on the order sheet, as well. DSS had one fork ear and another one was found on eBay.

On the bright side, the fuel tank had been cleaned and lined, so that task was already handled. The petcock needed an overhaul, but fortunately the repair parts for these models are plentiful.  A new battery was locally ordered, which is substantial considering the bike does not have an electric starter system to power up.  The muffler had surface rust, especially on the exhaust flanges, but there were no holes underneath the end of the muffler assembly, which is a rare occurrence these days.

My friends at 4into1.com offered some tire/tubes/band sets at a discount, so two sets were ordered, as they fit both the CL175 wheels and the CB77! The forks needed new seals and fork boots, so those were ordered, however the “fits CL175” eBay seals were 31x43x10 vs. the required 31x41x9.1 sizes. I finally just ordered seals from my friendly Honda dealer and got them in a couple of days. 

That all went together okay, however when the front wheel was removed, not only was the drum surfaced rusted over, but one of the brake shoes had NO brake lining in place. Apparently this bike was used as intended (i.e. a Scrambler) and driven through Oregon mud and streams, plus was suffering various oil leaks at seals and gaskets. One supposes that the front wheel was submerged a few times and left to stand as-is. Eventually, the lining on one shoe unglued itself and probably jammed the front brake when the bike was moved, so the wheel was removed and the loose lining removed, and then wheel reinstalled with only one brake shoe working.

Brake shoes were another “fits CL175” issue, when the ones that were supposed to fit were found to be too small and not the cross-match that was indicated. Another confirmed part number shoe pair was found on eBay and they arrived quickly. In the meantime, there was a LOT of rust removal of the brake drum surface and the rest of the brake hardware to do. Both wheels needed to be de-rusted and deglazed to allow proper function once again. The brake cams were locked in place, but judicious use of some penetrating oils and a soft hammer got them freed up so they could be cleaned, lubed and reinstalled. 

The new Michelin tires were installed on both wheels giving it a more modern look.

DSS came up with a nice reproduction speedometer cushion, which happens to be the same as the one used on the CB450K0 Black Bomber. New cables were procured and slowly the bike regained some form of motorcycle look and function. The chassis was cleaned with S100 and scrubbed up a bit so that some anti-rust treatment could be applied followed by most of a can of Duplicolor Gloss Black spray paint.

Rebuilding the top end of the engine was risky, in that the cylinder bores were somewhat roughed up from the seizures and the intake valves had typical cupped wear at the seat edges. The valve seats in the head were somewhat rough condition and one had a deep rust spot right in the valve seating area, which required more and more cutting and narrowing of the seat until the corrosion pitting was erased. The intake seats were touched up slightly and the new contact area was very narrow and problematic.

After several rounds of scraping, chemical cleaning and scrubbing, the engine assembly was finally installed with a bit of patina intact. After working out all the wiring connections and setting up the ignition timing, the engine was finally fired up for the first time in many years. Once the bike was running, I listened and watched for signs of distress of any kind. There was smoke out the muffler, but a lot of that was due to the old buildups inside the pipes and muffler that needed to burn off as the engine came up to temperature.

The engine took throttle crisply but didn’t want to idle down without dying. Ignition timing was rechecked and the left carb removed for another look as it only ran decently with the idle screw backed out about 3-4 turns vs. the correct 1 to 1.5 turns from the factory tune up manual info.  I rechecked the valve clearances to make sure that one of them hadn’t sunk into the seat but all seemed okay there. Finally, I ran a compression test and found 120psi on the right side and only 90 psi on the left. I hoped that running the bike in for a few miles might help seat the rings and the valves more forcefully and bring up the compression readings. The bike felt quite crisp under power in all gears and I enjoyed my 3-4 mile local test run, but on the return the engine continued to quit when allowed to idle again. Follow-up compression readings verified that nothing had changed from the earlier readings.

New intake valves were ordered and will have to be installed when the engine is dropped down for inspection and repairs. I did notice a good bit of oil coming out of the breather tube after the test ride, indicating that the piston rings were still not bedded in yet, however the spark plugs came out nice and dry on the tips, so it wasn’t pumping oil into the combustion chambers. There was no visible smoke out the muffler either, which was a good sign. Unfortunately, the right side spark plug hole threads are somewhat damaged and will probably require an insert to shore up the thread hole. This can all be done when the head is removed for new valves. This is the kind of experience to expect sometimes when you are in a hurry to get a job done and get onto the next stage of the project and/or other projects that are backed up currently.

Reflex Reflux – a Space Odyssey through the Van Honda belt system

This somewhat sad and frustrating story began several months ago…  My friend Burt called for help with his 2007 Honda Reflex 250cc Scooter, which had suddenly died on the highway and wouldn’t restart. I jumped in the Tacoma and found myself within 100 yards of the Mexican border where Burt was waiting with his stricken scooter. We loaded it up and hauled it back to the Santee area shop where it was left for diagnosis and repairs.

Burt checked for fuel and spark and compression, all of which were present in what seemed to be stock specifications, however the engine would try to start up initially and then just die for no clear reason. Restart and repeat, over and over again until the battery gave up the ghost. Burt bought a nice new battery for it, tried the restart and was met with the same results. He called me for some advice and I ran through the normal checklist of what was needed and what he had found. There were no clear clues so the troubleshooting became more and more esoteric and all kinds of possibilities discussed. Burt replaced the ignition module and the starter valve, but time after time, no improvements could be made. The carburetor came off for cleaning and inspection. Apart from what appeared to be a slightly plugged idle jet, nothing else seemed amiss. Stripping the bodywork off of these scooters in order to access the engine and fuel system is rather arduous and time-consuming, but wound up being repeated any number of times as different “cures” were tried and found to be lacking in positive results.

Burt had other bikes and projects going on in his life, but this Reflex become a source for “Reflux” as his mind churned over and over again about what to do, why it hadn’t responded to various repairs and the overall spirit of feeling a sense of defeated by mysterious mechanical ailments yet to be uncovered. Finally, in a desperate plea to me for hands-on help, so I agreed to take on the unruly 

Reflex to see if I could make any headway with it for him.

With the bodywork removed, I checked the compression which clocked in at 230 psi, right on the money. There was a nice steady spark at the plug, but when we tried to start the engine, it coughed and sputtered and then died quickly. The sound, to my ears, was that of an engine that was flooded/way too rich running. Removing the spark plug again, the cylinder spewed out a stream of raw gasoline which luckily didn’t ignite off of the nearby spark plug hanging on the plug wire. I drained the carburetor bowl and started pulling vacuum lines off the carb and intake which control various components of the emission control systems. When I pulled a line off of the top of the carburetor body and cranked the engine over MORE raw gasoline flew out of the uncorked port.  What the @#$%!% is going on here?

Obviously, the carb had to come off for inspection. It is buried down in the frame, but removing the manifold bolts and throttle cables allowed it to be worked free for bowl removal. What I noticed was that the float bowls do NOT have an overflow tube or way to shed excess fuel if the float valve sticks open. I removed the float pivot pin and float to check the tip of the needle. I happened to have a spare new needle on hand, but it didn’t make sense that the needle was really a problem. What WAS the problem was a tiny sliver of shaved off fuel line or an edge of an o-ring that was nestled down deep in the float valve seat! At first it looked like a bit of dirt or fuel varnish, but when I probed it with a scribe tip, it moved around the bottom of the seat. I dragged it out of the recess and looked at it carefully. Sure enough it was rubber something and it was just big enough to have blocked the float valve from closing all the way. The fuel pump kept pumping gas into the bowl which then was being sucked out of the carburetor bowl vent fitting. An errant placement of one of the vacuum lines on that vent fitting had intake manifold vacuum sucking fuel out of the bowl and back into the intake manifold as raw gasoline!  No wonder it was choking and sputtering when we tried to start it up!

I was getting more confident that some substantial progress was happening now and after the spark plug was replaced in the head, the engine fired up immediately sounding strong and showing no signs of stalling out. While I was revving the engine to clean out the cylinder from all the raw gasoline inside, Burt noticed that the rear wheel wasn’t moving at all!  Honda belt-drive scooters use variable pulleys to adjust engine load and vehicle speed. The wheel should start moving immediately as the throttle is applied from a stop. This one did NOTHING! Big clue… the original breakdown failure on the freeway was a broken belt! The belt fragments wrapped around the crankshaft pulley and kept grabbing the engine as it began to run. The engine and all systems were probably just fine when the belt broke, but you can’t see the belt inside the belt case and the “symptoms” were that the engine didn’t want to start and run. Normally, those symptoms are related to lack of fuel or some kind of CDI breakdown or other component failures. In this case, the engine systems were okay, but the belt drag was keeping it from operating again.

Burt wrapped up the bodywork and we loaded the scooter back into his Nissan pickup. He reported that the belt was mostly fragments, with maybe 1/3 of the length still intact. Once he finds a new belt, the bike should be good to go, once again. Finally, the sleepless nights and acid reflux symptoms are subsiding for Burt and the bike will be going up for sale, as soon as he completes the final repairs. It was a long and frustrating challenge for Burt and his various advisors. Before he brought the scooter to me, he had taken it to two repair shops for diagnosis and they sent him off with no further insights as to what the problem might be, apart from observing that the scooter needed tires and a right fork seal!

So, after a couple months of trial and error, the Reflex Reflux case is now finally concluded and it will again be able to fly through the Van Honda Belt with speed and efficiency as designed.

Busy, funny, scary news updates…

I haven’t been very consistent in my blog postings lately, due to a number of situations that have arose over the past month…. But I’m BACK now.

Let’s see… There was the matter of the CL125A, which needed some attention for oil leaks, fresh rubber and some performance/appearance issues. The shift shaft seal was replaced, new fork boots and one fork seal were replaced, new tires/tubes installed and the muffler was welded up on the inside where a hole was rubbed through from contact with the shock absorber. A new battery was procured, of course, and the fuel system cleaned and re-jetted for modern fuels. It was too underpowered to make the hill nearby which leads to the post office, so the bike was offered up for sale and found a new home in Ventura, CA as a result of an eBay auction. The buyer had one just like it when he was a kid! That will sell a bike every time, when you find that right buyer.

Busy, busy

While that one was pending sale, a 1982 Honda FT500 Ascot showed up in running condition, but needing some TLC in the usual places that these bikes require. The air box was cut in half, which allows a large K&N air filter to be used in conjunction with some adapters to allow use of the crankcase breather system. The bike has a custom-made rear luggage rack that even included little LEDs in the back end of the rack rails. The owner worked at a metal fabrication shop and thoughtfully created a sturdy rack for his lunch box, while commuting to work. The seat cover was original and splitting apart, so a nice aftermarket replacement cover was procured and installed with the help of an upholstery shop. My staple gun didn’t have enough power to put staples into a plastic seat base. Fortunately, the seat foam was still intact, so a cover was all it needed to make it attractive again.

After some trial runs, it seemed that the carb jetting was a little off. The spark plug looked pretty good, but there was a flat-spot off the bottom into mid-range that was annoying. All the testing revealed an oil leak at the camshaft rocker arm cover, which was an ongoing problem with those bikes and the related XL500s back then. I ordered a gasket kit (EMGO) but the head gasket was less than stellar. A couple of the bolt holes were off by half a hole. That necessitated some gasket mods to get it to go together again. The camshaft lobes were somewhat pitted, but not necessarily from lack of lubrication. This seems to be another problem area for these bikes, perhaps due to insufficient surface hardening. When the rocker cover was removed, it was evident that someone had been in there before, as a number of bolt holes had inserts installed to repair stripped out threads. Again, this is another long-standing problem with these bikes.

The balancer shaft adjustment can only be made by removing the clutch cover. The spring-loaded tensioner arm moved a couple of notches before coming to a stop. Honda recommends backing off the tensioner one notch from where it stops.

When the carburetor was removed for inspection and jetting, it appeared that the slide piston was somehow jamming up into the top cover, so the throttle never really fully opened to full power. A friend had some CX500-650 used carburetors, which share the same components as the FT500s, so that fixed that problem. Eventually, I would up with a #150 main jet, the CX500 needle with shims and a larger idle jet to finally solve the performance issues.

The bike came with bar-end mirrors, so I wound up spending over $100 for a set of OEM mirrors, which are just about gone from anyone’s stock now. After a test ride, the right front turn signal lens promptly broke off and fell into the street as I came up the driveway. A pair of OEM lenses was found on eBay for $15 including shipping, so now I have a spare, just in case this happens again. I have never seen that happen before! It was like something out of a comedy show… ride, ride, clink, clink…. Stop and recover the lens from the driveway. All the other three seem to be just fine.

The electric starter systems on these bikes are somewhat problematical so the covers were removed and the system inspected, cleaned and serviced. So far, it is working well now. The FT500 is up for sale now, as I continue to try to trim down the motorcycle herd nestled in the driveway.

Funny/sad

The last three people who reported hard starting problems had bikes with battery levels that were WAY TOO LOW to allow the battery to charge up and stay charged. These lead-acid batteries need regular checking at least once a month.

Sad/scary

Finally, a long-time customer rang me up to ask about redoing the top end on his CT90K1 Trail 90. In general, parts have been available from Honda and the aftermarket for many years. Honda must have build a couple of million of the OHC 90-110cc horizontal singles since their 1965 introduction. Honda placed those engines into ST90, S90, SL90, CT90, ATC90s and many, many more.

Taking the top end off is about 15 minutes work, even with hand tools, so the autopsy can be done quickly when there are problems. The bike was using smoking and using oil since the last visit, so the focus went to the piston/rings/cylinder bore primarily. Despite a smooth-looking bore, when the top compression ring was removed and fitted to the ends of the bore, the bottom measured out at .008” while the top measurement was out about .020”+, so obviously there was a taper in the cylinder bore.

The bike only showed about 4400 miles on the odometer, but the overall condition was fair-average. The bike has been used as designed, out in the sand, gravel and general off-road conditions. When the piston was extracted, the first thing noticed was a loose-fitting piston pin clip, consistent with those found in a lot of Chinese-made piston kits. The piston was marked 028 (product code for an S90), but it had a 3 piece oil-ring, which the bike never came with from the factory. I wondered why a low-miles bike would have a replacement piston until I removed the carburetor and discovered that the little choke flap was missing from the choke plate! It was another case of flap failure, which I have seen on many of these kinds of carburetors made in the 1960-70s. The spring loaded flap fails and gets sucked into the engine, where it usually jams the intake valve open long enough to have the piston come up and bend it smartly. The valves in the head were cupped at the seats, so new valves were ordered and fresh valve seats cut in and the head assembled for final work.

There wasn’t any sign of catastrophes inside the combustion chamber, but the head could have been changed when the piston was damaged along with the valve. There were a few Heli-coils in the threaded holes, so obviously someone had been inside the engine at least once before it came my way. When I started looking for an over-sized piston, I discovered that Honda has discontinued the S90 series pistons and ring sets from US inventories! It is one of those things that will last forever, but I see that this isn’t the case now in the 21^st century. I was able to find one set of OEM rings at a Honda dealer up in Orange County, plus one matching OEM piston from an eBay seller in Texas. I tracked down a pair of 14mm wrist pin clips after going to two different dealerships….. ?!?!? It really is shocking that you cannot find wrist pin clips in stock at a motorcycle dealership these days. The first local dealer didn’t stock them and the second one, some 12 miles away only had two available. I guess people are not rebuilding their bikes much anymore….  Sad isn’t it?

I did find that the camchain was pretty well stretched, so a new chain and guide roller were ordered up, along with a quality Vesrah-branded gasket set. These engines have a valve stem seal on the exhaust valve side, which was replaced with a spare that was in stock, but it was surprising that the complete gasket set didn’t have this tiny part included.

Two 25-mile round trips later to drop-off and pick-up the newly bored cylinder yielded a nice smooth, straight and round cylinder to fit a new piston into, now at factory specs. As fast as it is to tear down one of these engines, the reassembly/repairs take several hours. The valve job probably took about 45 minutes as the seat contacts were adjusted several times until they centered on the valve head. Scraping gaskets, checking threaded holes, replacing seals, doing a valve job, cleaning parts and carefully reassembling this little engine takes a lot of patience and some expertise.

With the carburetor cleaned out, float adjusted and some new gaskets/seals installed the engine finally was ready to run, once again. The engine fired up after a few kicks and once the oil solids coating the inside of the exhaust system burned off, the engines ran smoothly, with little noise or smoke evident now. It will probably receive a slow break-in period at the hands of the owner who has enjoyed it, even as it was, for many years.

The CT90s have a dual activated rear brake, which also incorporates the brake light switch. If either of the rear brake functions jams up, the brake light will stay ON and eventually run the battery down because the little 6v system is barely up to the task of keeping a fully-charged battery up to normal voltage levels. This bike was a 1969 CT90K1 which had a front brake light switch function as part of the brake cable. The cable was changed to a non-switch version, so loose wires are flying in the wind at the front fork area. Honda made many changes to these bikes through the years, so keeping them stock with OEM parts is a challenge now. 

I think that brings us up to date so far… MrHonda

Coming through in the clutch… Honda 250-305 clutch history

One of the most confusing aspects of 250-305 engine repair is sorting out the numerous versions of the clutch assembly. I will attempt to demystify it here, if possible.

Honda began the new wet-sump engine series in 1960, starting with the 250cc Dream, then adding the 305cc version soon afterwards. In 1961 the CB72 and CB77 Super Hawks emerged from the factory, followed by the new 1962 CL72 250cc Scramblers.

Honda started with a light pull, conservatively-designed 4 plate clutch used in the first generation C/CA72 250cc Dreams.  In the parts books, you will see these parts with 259 part codes, which is the code for the 250cc Dream engine series. With the somewhat higher power output of the 305cc engines, the parts were upgraded to 266 codes for the clutch pack and the primary chains. Yes, there were three different parts numbers just for the primary chains, starting with 259, then 266 and finally the 268 code part for the CB72.

The thick 5mm friction discs of the 250s, coupled with very light clutch pressure springs resulted in clutch wear and failures fairly early on in the production cycles.

From the 1960 Dream parts books we see:

The 250s had four thick friction plates and four steel plates. The center hub had no grooves for retainer springs. Early pressure plates have been seen with small metal pegs inserted around the edges with tiny coil springs attached, which helped push the clutch assembly apart during disengagement. The 305s had five sets of thinner plates. One set of clutch springs sufficed for both versions, at first. Apparently clutch wear and failures became common, so a new set of clutch parts were designed for the Dream engine applications. Notice there are two clutch outer part numbers. The first is a solid mount rear chain sprocket style and the 010 version was the improved “cush drive” model. The inner clutch hubs came in two more types using the stopper rings, fitted into grooves machined into the clutch hub. Ring groove locations varied due to the differences in the thicknesses of clutch plate pairs which were being retained by the stopper rings. 

Clutch springs were offered in 259-000, 259-010, 266-000 versions, which became progressively stronger, as necessary. Clutch centers were offered in 259-000, 259-020, 266-020 and 266-030 for 250 and 305 models, respectively. The early model clutch friction plates were molded solid fiber material. As the clutch designs progressed, the 268-020 coded friction plates were made in aluminum-backed parts with the friction material bonded to the metal backing. Friction materials varied in thicknesses depending upon the application and number of plates used. Dreams wound up with either 5mm thick, 4-plate clutch packs or the thinner 4mm 5-plate combinations. The Plate “A” (first plate on the hub) was generally 2x the thickness of the other steel plates. Steel plates come in several thicknesses, so just the right combination of parts needs to be achieved to create the best possible clutch pack build.

What is important to remember is that no matter what combination of friction and steel plates were used to complete the clutch pack, they ALL had to have the same stack height when installed on the engine. If the stack height isn’t matching to OEM specifications, then the clutch release components inside the right side kickstarter covers will not have the correct geometry to effectively release the clutch pack when the clutch lever is pulled in. The clutch lifter arm must travel through a shallow arc, starting below horizontal plane and arcing upwards above horizontal. As the clutch lifter arm moves within the clutch adjuster (fixed in the kickstarter cover), the coarse threads of the two parts create a pushing motion on the end of the clutch release pushrod, which contacts the big ball bearing nestled deep inside the clutch lifter arm.

Many people have discovered sudden loss of clutch lever action, usually when the kickstarter covers have been removed for servicing or clutch cable replacement, due to the ball bearing dropping out of the lifter arm hole. The thickness of the ball takes up considerable amount of lateral play in the clutch release mechanism, so when it is missing it is impossible to adjust the clutch free-play using the cable adjusters or the clutch adjuster on the side of the kickstarter cover.

Scrolling down these pages to the CB72-77 clutch parts list, you will see that there was a 6 plate clutch offered, a 5-plate version using all fiber friction plates and finally the last generation 5-plate clutch using the metal-backed friction plates. Obviously, in order to accommodate a 6 plate clutch pack, all the plates needed to be thinner than the 5-plate set. The last generation CB72-77 (and CL77) used a clutch center with retainer grooves placed to allow the thicker plates to be installed and retained. The last of the steel plates had anti-warp notches stamped along the inside edges to help keep the plates flat when they became heated during aggressive operation. The Plate A is quite thick and has a beveled back edge to clear the clutch outer when installed. Late version pressure plates have angled drain holes to help evacuate trapped oil inside the clutch assembly.

There were three different clutch covers first due to a change in the shift shaft lengths, then the progression from “small hole” to “large hole” outer oil filter cover sizes. Remember to check your new parts against the old ones, when doing replacement of components.

CB72-77 clutch springs went through a series of part number changes from 268-000 for the 250s, followed by 275-000/010 for the 305s, then to the very stout 275-810 racing clutch spring. For most normal stock street applications, the 275-000 spring (equivalent to the 323-003 CB500 Four spring) works fine with stock clutch pack parts. These springs give a nice balance between light lever pull and sufficient pressure to prevent clutch slippage. Use of the later 275-810 springs will give the rider a very heavy lever pull experience, but does ensure that clutch slippage is pretty much non-existent.

When there is wear inside the clutch adjuster threads, there is a progressively lessened amount of clutch pushrod travel to disengage the clutch plates. The wear increases the amount of force needed to disengage the clutch to the point where the combination of heavy springs and worn clutch release parts can cause damage to the early version kickstarter covers. Later versions of the kickstarter covers were designed to move the clutch cable joints more forward, closer to the cover retainer screw mount.  Increased strengthening ribs were incorporated into the cover design to help prevent breakage which is especially common in the Super Hawks, which have forward-kicking kickstarter levers.

Well-lubricated clutch adjusters with minimal thread wear will enhance clutch lever pull efforts in a positive way. Heavy clutch lever pull effort is often a combination of dry and worn (and misrouted) clutch cables, worn clutch lever pivot bolts/holes and excessive clutch adjuster thread wear.

CA clutch parts list (1969 book):

                                                CB kickstarter cover... ready to install.

Final conclusions:

You cannot indiscriminately mix and match Honda friction and steel clutch plates and have a normal operating clutch on a 250-305. Steel and friction plates come in various thicknesses and designs.

You MUST use the clutch plate pack that matches the inner clutch hub retainer wire grooves AND use the retainer wires, as designed. These “stopper” wires are becoming extinct, so I have used picture hanger wire or very thin safety wire to use for the same function. Installation of the plain wire requires drilling an additional hole in the hub and securing both ends of the wire inside the hub where the stopper wire ends usually wind up after installation. If you leave the stopper springs out, you will have difficulty in selecting neutral when the engine is running and you are at a stop light/sign and need to release the clutch in neutral while you wait.

The best solution is to use the 1965-ish and later CB/CL77 clutch assembly, which includes the cush-drive clutch outer and the sturdy 268-020 friction plate sets. See photo below for comparisons to your clutch assembly. Remember if the clutch pack stack height is not correct, clutch engagement/disengagement issues will arise.

Using a CB/CL77 clutch is perfectly fine in a 250-305 Dream. You might play with using some of the lighter clutch springs to lighten the clutch lever pull, as strong springs are not needed for Dream applications. The Honda 425 code springs are the superseded parts for the Dream clutch springs.

Using Barnett clutch kits will not allow use of the inner hub stopper springs, so clutch release at a stop sign/signal light will be compromised. Barnett plates tend to drag when cold and the spacer plate they use to compensate for the changes in plate thicknesses will cause problems for street use. IF you are racing your bike and don’t care about street use, then going for heavy springs and heavy duty clutch plates may be the way to go, but you will have difficulty getting the transmission into neutral without the stopper springs in place.

Watch out for late model “shallow spline” replacement parts, used on 1966-67 models. You can use the shallow spline hub, crankshaft sprocket and countershaft sprocket on earlier bikes, but not the other way around. The OD on the shallow spline parts are the same as the deep splined parts, so it is the ID which causes conflicts when trying to use early parts on late shafts.

 Honda has superseded the 259/268 steel plates to 329 code parts from the XL350.

Bringing them back alive…

It was another week of bike wrangling at Casa de Honda as the month of April winds down. Recent sales included a 2015 Sym 150 Wolf (after the BAT sale of the CR93 tribute bike, a Suzuki GN400 and the 2400 mile Yamaha XS650). Most recently, I swapped out a mint condition 2013 PCX150 scooter for a non-running 299 original mile 2008 Honda 250 Rebel.

If that wasn’t enough, I spotted a survivor 1968 CL125A Scrambler in the local Craigslist postings, which had been on and off their site for a week or so. When I contacted the seller to find out about the basics like: Does it run? Is it registered currently? Are there any big problems with it? Etc..

The initial response was “I don’t know much about motorcycles.” Digging deeper in the communications, it appears that the bike was bought because it “looked cool” and it was a first motorcycle purchase for him. As I expected, it was a good 10-footer, but when you got close-up it became obvious that the bike was basically all original: cables, tires and body paint. The tank had been re-sprayed with some kind of close to Honda Silver color, but the rest of the Candy Blue paint was untouched, apart from the scratches, dings and general wear and tear that you would find on a 49 year old baby Scrambler.

Both bikes needed new batteries and fuel system maintenance. Despite the stinky green fuel that exited the petcocks, the carburetors were relatively easy to clean after wrestling them out of their respective chassis. These two bikes must be somewhere in the TOP 10 of “hard to remove” carburetors category. The CL125A carb is sandwiched in between the cylinder head intake port and the rigid air cleaner tube that flairs out over the opening in the frame. The only way that I could see to remove the carburetor was to take off the two 6mm nuts, then, using Vise-Grips, work the two intake studs out of the head, so the carburetor could slide sideways out of the frame.

The idle jet was plugged up and all the rest of the jets and emulsion tubes were cleaned and checked for open passages. This was Honda’s first attempt, that I know of, to create a CV (constant velocity) carburetor. The slide has a delicate rubber diaphragm secured to the top by way of a plastic plate with 3 tiny screws attached. In the middle of the plastic plate is a spring-loaded plunger which is pressed down by the carburetor arm which resides inside the top cover. While CV carbs on 350 twins from 1968-73 used a light spring to press the slides down in the carburetor body, the tiny slide on a 125 (remember this is a 360 degree firing engine with a single carburetor) is too small to control in the same manner, so Honda put a big heavily weighted spring in the top cover to push the slide down firmly whenever you let off the throttle.

While the diaphragm was probably original and felt/sounded very brittle, there were no holes or tears in the rubber, so it was gently reassembled and seemed to hold vacuum properly. The carburetor flange is sealed with a 32mm o-ring, which has been discontinued from Honda. I had been buying some various sized o-rings from eBay sellers in China for use on Honda Dream carb flanges, so one of those was popped into the groove when the carburetor was installed.

The fuel tank was purged of the old gas and refreshed with some of 7-11’s finest 91 octane brew. With a new piece of OEM Honda fuel line, the carb was again reconnected to the fuel supply. The original battery was a small electronics store item, which was marked “Removed in 2003.” The battery wire ends were changed to the small push-on connectors, but I had ordered an old-school lead-acid battery which is big enough to support an electric starter, but these bikes never had that option. I snipped off the wire ends and found some ring terminals that would fit the 6mm battery bolts normally used with these batteries. With the fully-charged 6v battery installed, the switch was turned to ON and the bike lit up with all functions working as designed. Yeah!

With fresh gas on the tank, A few good kicks and the bike started up, sounding sweet and healthy with no smoke out the muffler (thankfully no muffler rot for some reason). The original tires were rock-hard, so a brief and gentle spin around the block was enough to confirm that the transmission and clutch seemed to be working properly.

2 weeks later…

The little CL125A was treated to a new set of tires and tubes, plus fresh carburetor parts that amounted to $60 worth of purchases. I re-learned a valuable lesson about setting up the carburetor diaphragm system when I installed the central plunger in upside down. There is a long and short end to the spring-loaded plunger and when it is installed with the long end up, the throttle goes to wide open revs as soon as the engine lights off. This is VERY disconcerting, to say the least. After a few rechecks, I finally looked at the illustrations of the carburetor and saw that the long end of the plunger goes DOWN. Properly installed, the carburetor assumes normal function once again.

The exhaust system is all stock and the drain hole at the back was still open and there seemed to be plenty of material underneath the muffler, instead of finding the usual rot that happens with time and operation. When the muffler was removed, a surprising hole was discovered on the back side of the muffler relief where it curls around the rear shock. Apparently the rear mounts were bent or not installed correctly and the shock wore a whole in the muffler body. A trip to my friend Rob North’s shop resulted in a mended muffler which then needed a hard-to-find muffler packing for the slip-in left exhaust header pipe. After tracking down a small batch of them, the muffler was finally installed and should function as designed.

NOS old school cables were ordered and installed. The clutch cable installation requires removal of the rear sprocket cover which revealed that the front sprocket was a 16t instead of the stock 15t size. Test rides showed that the bike was unable to sustain a good speed up the long hill to the house from the local PO. It would rev high in 2^nd to about 40 mph, then just bog down in 3^rd gear under full power. A 15t sprocket was ordered and installed when the cable was changed. The clutch adjuster was found to be extremely tight in the side cover, requiring cover removal and a good bit of time to extract the adjuster and then refit it in the hole so it turned more easily. All these little tasks wind up taking up quite a bit of time to correct during a revival process…

Next improvements are a new right side fork ear, fork seals and a new headlight rim.