Well, this was round two for this 1967 CL77 Scrambler with a 68+thousand serial number. We don’t know what the last CL77 serial number was, but I seldom see them very high into the sixty-eight thousand numbers. Earlier this year, the bike was in for a slow-return idle problem that was caused by a missing camsprocket return spring. I did a sprocket-ectomy with the engine still in the chassis, which can only be done on a Scrambler. That went well, but the owner was complaining about the big jump to 2nd gear and also some intermittent shifting problems. Plus, he wanted to do the X job on the transmission gears, so the 1-2 shift gap was closer together than it is in the stock configuration. I can’t think of any other transmission that allows you to do this kind of reset of the gear ratios. You get a closer 1-2 and 2-3 gear step, then a larger jump to top gear. For general street driving, this is a preferable update.
1st gear 2nd gear 3rd gear 4th gear
Stock
17.52 10.46 7.32 6.26
"X"d
17.52 11.70 8.26 6.26
I worked on the clutch when it belonged to the previous owner and I was the one who put the two gentlemen together to seal the deal and bring the bike down to San Diego from the previous location in Central California. The late model clutches are the best version to use on these engines, in that they have the cushioned clutch basket, the later 5-plate clutch pack and the outer pressure plate with the angled drain holes to help facilitate the expelling of excess oil trapped inside the clutch assembly.
One of my least favorite tasks is to R&R the engines out of Scrambler chassis for service work. With all the brackets and bolts and misc bits, it generally takes me about an hour to extract the engine and about the same to re-install one. I had the bike up on my bike repair rack to do all the removal steps, then lower it down so I can ease the 100 lb lump out of the frame and onto my little rolling cart. Fortunately, I have had an occasional helper who comes to learn about my work and he was strong enough to just grab it off the dolly and hoist up onto the work bench.
I had drained the oil previously, but more than a little gets trapped inside the bottom case which oozes out when you turn the engine upside down to remove the bottom case half. Starting with the two nuts on the top case, which hold the transmission cover bracket in place, the rest of the fasteners are all on the bottom. But to get to that point, you have to remove the clutch cover, oil filter, crankshaft locking washer and nut, then remove the clutch pack. The primary chain and front sprocket come off as a set and then you are down to removing the shift shaft and gear selection hardware. The primary tensioner and mounting hardware are then removed and you are ready to roll it back on its head, face-down to access the nuts and bolts that hold the cases together.
The engine had just over 10k miles and was in generally good condition internally. There was the usual layer of gunk on the bottom of the case as well as an 1/8” of collected crud inside the centrifugal filter. The gear dog engagement was minimal in the 1-2 gearshift steps and the shift forks had some scarring from being jammed into gear repeatedly. Pretty normal stuff, I find, these days.
The shift drum tracks were in good condition. I replaced the low gear bushing and reused the original kickstarter pawl/spring/cap. I have only a few remaining offset gear cotters, which are the “fix” for transmissions that jump out of gear due to a lack of gear dog engagement. I used 4 of the .020” first step cotters to move the engagement of the gear dogs closer together. Doing the X swap of the middle four gears also gives the corners of the gear dogs a better chance of a clean grab to the adjacent gear.
In the end, the gear dog engagement was probably 75% on both shafts, ensuring that the gears will stay engaged when selected. There is a certain amount of slack and float of the gears on the shafts, but this setup seemed to be a best-case scenario.
We had new reproduction low gear bushings made a year or so ago, which is always a requirement on most engines that need transmission repairs. Unfortunately, the offset gear cotters which were especially made by Honda to address the engagement problems were made from a hardened stamped steel and are not easily reproduced. I’m not sure what will become of all of the future engine and transmission repair jobs when the supply is permanently exhausted.
I replaced the shaft seals, cleaned the case halves and resealed the cases with MotoSeal. All the nuts and bolts were cleaned on the wire brush and installed where they belonged, torqued to specs. The oil pump was checked for flow and reinstalled on the bottom case. The engine doesn’t sit on the bench very well because of the cast-in boss on the bottom of the Scrambler oil pumps. I block it up with wooden blocks and reassemble the shift selection parts, the shift shaft, the primary chain tensioner and the whole clutch pack. The clutch cover gasket was a special extra thickness part from an eBay gasket company, called Emerald Gaskets, who is willing to make gaskets of over-OEM thickness material. So far, the gasket has held up okay after two removals. Leaking clutch cover gaskets are the biggest challenge to keep dry on these engines, so I am glad to find a product that works.
The engine was fitted with a Pro-Trigger electronic ignition system, which needed a bit of adjustment to get both sides to time up to the F marks. The carburetors were rechecked and float levels adjusted slightly to 22.5mm. The stock idle and main jets were kept in place. OEM needles, thankfully, were retained in earlier service work. The Keyster kit needles seem to be out of spec for these engines.
I was able to wrangle the engine down off the bench, stopping at the edges of the open drawers and then onto the little dolly cart. I wheeled it back to the waiting chassis and was able to lift it up about 6 inches to start it into the frame. I had already removed the left side exhaust studs which always seem to make thing difficult if left in place. Lifting and twisting, the engine finally found a home in the frame, but had sunk down below the engine mounting holes.
The bike was rolled back onto the work table and then a small floor jack again used to raise the engine just a little bit at a time, high enough to start some mounting bolts in place. The long bottom bolt and spacers have to be aligned just so, in order for the bolt to be inserted all the way across the frame, ducking into the oil pump boss and out the other side.
Once the engine mounting bolts are inserted and tightened down, the rest of the assembly continues, installing the carburetors, air filters and tubes, the exhaust system and stator wiring, etc.
1.5 liters of Honda GN4 10-40 oil was funneled down the oil dipstick tube and the footpegs installed as one of the last steps.
I had drained the gas tank in order to inspect the condition of the petcock. There was some leftover scale and deposits inside, so it was given an acid bath to dissolve the deposits and then flushed with clean water. Rolling the bike back off the rack, it was time for a start-up try. It came to life in a couple of kicks and sounded as normal as a CL77 can be. It still has the full weld-on muffler exhaust system, but they still have that distinctive Scrambler sound.
The customer lives here in San Diego and rode the bike in and then back home again. His bus pass gives him some other transportation options, rather than having to borrow a truck or trailer to bring the bike to me. His final wish was to have the tank and side covers re-painted Cloud Silver instead of the Candy Orange that was supplied at the factory. He rode the bike back home without incident and then hauled the bodywork off to my painter friend for a refinish.
This transmission repair took an easy 9 hours of labor, but it certainly was not “easy” work. I much prefer to work on Super Hawks and Dreams for engine repairs. But, this year has mostly brought CL77s to my garage, so you just have to do what you have to do…
Bill Silver
aka MrHonda
www.mrhonda.guru, www.vintagehonda.com
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