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.
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.