Thursday, June 14, 2018

Back in the saddle with 250-305s again…

After running through a handful of interesting JDM bike and thinning out my little herd, the inevitable return of 250-305s began in the past few weeks.

Chapter 1:  CB77 for sale... not bought
A friend alerted me to a CL posting for a 1965-ish CB77 for sale at $1100 asking price. Photos showed oversized tires on both ends, missing fenders, an a/m seat and the wrong mufflers, just to start with. The bike was 50 miles away, but I already had some business in the area so it wasn’t too much trouble to cruise over and have a look. The seller was a nice mid-aged man who had put together a cafĂ© CB550 project and had gotten the CB77 from a friend who first wanted to make a custom bike out of it, then decided to sell it as-is. Photos did it too much credit as the chassis had been modified around the forward seat mounts and the black chassis had a red front end attached. The ignition switch and the fork lock numbers didn’t match, so I assumed that the front end was replaced from another bike.
It wasn’t running due to dead battery, stuck carb slides and the usual faults found on a long-abandoned project bike. It needed a chain guard and a new wiring harness, which I happened to have left in my parts stock, but the more I considered it the more I kept remembering all the CB77s that I spent endless hours on to get running, then wind up selling them for what I had spent on parts and services. Somehow I found the strength to say NO, even to a reduced price of $800. I was proud of myself for walking away from another “project” that would have no financial reward at the end, whatsoever.

Chapter 2: Domestic CL72 engine rebuild
A few months ago, my longtime friend J. Braun inquired as to whether I would “rebuild my CL72 engine,” which I assumed would be just doing the engine, brought down in a box. After a long, long haul from UT, he arrived with a whole CL72 Scrambler in the back of the truck! After some discussion, I offered to remove the engine while he went back to his overnight lodgings to check in, then he would come back to pick up the chassis and haul it back home the next day. I had the engine out in the first hour and the top end removed from the “stuck” engine by the end of the 2nd hour. We went to a nice Italian restaurant for dinner, in celebration of my 70th birthday, then he brought me back home and we loaded the chassis into the truck.

The following day, I spent another 2 more hours carefully disassembling the very dirty and corroded engine which happened to be a domestic Type 2 (360 firing crankshaft) model. Fortunately, the crankshaft seemed to be in great shape, so the rest of the work will be extensive cleaning, prepping a spare set of cylinders for use and rounding up the required expendables like seals, gaskets, primary chain, camchain, bushings and kickstarter pawl bits.

The pistons removed were already .25 oversized, but were stuck in their bores due to water going down one intake side, through the carburetor and into the cylinder. The bike was last ridden in the early 1990s and then left in a corner of a shop for the next 25+ years. J remembers riding the bike, but seemed unaware that it was a Type 2 powerplant. The bike did have a kph speedometer and the remnants of the factory turn signal switch on the right side handlebar end. Most of the winker system parts were long-gone, but the original heel-toe shifter remained. These bikes came with non-folding driver footpegs and among the parts were 2 sets of NOS 273-000 footpegs to match the application.
It seems to take a couple of weeks to get all the parts cleaned properly and replacements lined up for the reassembly process. Overall, the engine components are all usable, without any of usual broken fins and similar damage often found in a bike like this which was being used as designed… as an on-road and off road machine.

As an unexpected bonus, J brought down 6 boxes of mostly NOS Honda parts for Scramblers and Super Hawks. There were a couple dozen of those little standup envelopes containing many small parts needed to rebuild these engines. There was spare ignition switches, unused and used, plus CL72 air filters, many sets of levers, NOS CB77 black cables and a variety of interesting bits. A good bit of it will go into the engine rebuild, with the rest offered on FB forums or eBay if all else fails.

Chapter 3: Return of the 1962 CB77 #25
It was old-home week as a revived 1962 CB77 with frame number 25 returned here for some troubleshooting and maintenance updates. I had received the bike as a rusty, corroded hulk with seized engine and lots of damage from moisture due to its long-term storage near the ocean, inside a shipping container. I only had 30 days to complete the revival, as I was scheduled for knee replacement surgery on day 31. I had written the whole story for my former internet host, the “” site which suddenly went dark a few years back. Fortunately, I had all the original stories saved on my computer and made a backup copy from the website before they closed.
The repairs were massive, despite the bike only having 2300 original miles showing on the speedometer. Even the tires and tubes were original OHTSU branded from the factory and while in terrible condition it was worthy of a quick rebuild and documentation of what exactly was and wasn’t changed on the first day of production for the 1962 models.

The bike was sold to a LA enthusiast who is active in the LA region of vintage Japanese motorcycles. With little break-in time, he rode the bike all the way out to their annual Death Valley desert run, which was some 350 miles away. The bike survived the trip and actually made another run the following year. With changing priorities, the owner decided to put the bike up for sale, but the Super Hawk began a series of misbehaviors, including dropping the left side cylinder intermittently. To help regain reliable ignition functions, a new electronic ignition system from Charlie’s Place was purchased and installed. The way the system is designed, there are some limitations as to the positioning of the control module which prevented installation of the point cover, if moved much beyond the center of the adjustment slot. The trigger wheel, which attaches to the end of the points cam can be installed in a 90 degree spread of options, so for successful installation the trigger wheel must be set, tested for timing function and then adjusted again when the timing was excessively advanced or retarded.

The instructions were a bit vague and there was a lot of trial and error until the full function was understood and the final adjustments locked in place. With the ignition setup correctly, the bike fired up immediately. I had checked the compression and idle jets for being clear, prior to finalizing the ignition timing. The bike warmed up quickly and I decided to take it for one last test run before it disappeared from my life forever. I barely got a ½ mile away and noticed that the clutch was slipping under anything more than half throttle. Coming back up the test hill nearby, the clutch was slipping and sliding all the way up, unless the throttle was modulated carefully. Then, there were the oil leak issues, which had been mentioned previously. A quick look showed oil coming out of the outer oil filter cover, down the tachometer cable and the shift shaft seal. All the next work was to be on the left side of the engine, so I had hopes that most of the leaks could be solved with replacements of o-rings and seals.

So, the unplanned services now included a clutch inspection, which requires draining the oil (good thing as it was needed anyway) and removal of the left side clutch cover to access the internals. Once the cover was removed, everything inside still looked pretty clean and shiny inside. The clutch was the original 6 plate version, to which I added some 323 coded (CB500) clutch springs which normally prevent clutch slippage. All the plates seemed pretty good still, so I bumped the springs up to some 374 code parts, which are for the CB550 and are a big longer than the CB500 versions. Before the clutch cover was reinstalled we checked for clutch lever pull effort, which seemed to still be reasonable to both of us.

I replaced the outer oil filter covers two o-rings, installed a new shift shaft seal and rechecked the cover for any high spots which can cause common gasket leaks in these engines. With the engine buttoned up and new Honda GN4 oil added, the bike was tested once again and this time the clutch function was normal, but the oil filter cover still had a bit of a weep even with new o-rings! I suggested that he make a thin paper gasket and seal the cover that way, which seems to be the only other way to contain the leak. It is an uncommon problem in my experience, however this early engine had the “small hole” cover and filter cover, which was revised later with a larger access hole and an extra o-ring in the clutch cover case to help seal it more effectively.

Starting at his 9am arrival time, we worked continuously until well past 1pm on Memorial Day. All the work paid off in getting the bike up and running, plus curing most of the unmentioned issues with the clutch and oil sealing problems. The bike is a solid example of Honda’s earliest CB77 efforts and an interesting transition bike from the 1961 year to some of the changes in the 1962 models. Looking at parts books, there were more changes to come as the 1962s continued in production, but this was a true example of what happened as Honda ramped up into the second year of Super Hawk sales.

It is bittersweet to revisit a bike that you built a few years before and then had to hand off to another CB77 enthusiast. Hopefully, the next owner will be inclined to spend some money and time on re-chroming and polishing the corroded bits that remain and give it a place of honor in their garage and out on the roads!
Bill Silver
aka MrHonda

1 comment:

  1. The Honda 305 motors either in CB or CL frames are now the "water shed" Honda's of yore. The sound of a finely tuned one coming down the street , you just know the sound and the exhaust note. How do I know. I ride a '67 CL77, original and unrestored. My very first bike which I vowed to keep after many future purchases. This bike took me all over Northern California and down the coast on Highway one past Monterey and Big Sur all the way down to Chula Vista and back home. Never missing a beat. Amazing engineering and reliability! She's a keeper and a reminder of how far we've come from the '60's.