Skip to main content
  1. Leisure
  2. Autos & Motorcycles
  3. Motorcycle Reviews

1969 CL90 partial dissection, diagnosis and revival... it runs and drives!

See also

Followup story to: http://www.examiner.com/article/a-honda-cl90-swallowed-whole-a-pt-cruiser

More Photos

Between wrenching on the 1962 CB77 and a V45 Magna that came in for emergency fuel system repairs, the CL90 has been sitting quietly beneath a cover. New cables were ordered up last week and the levers came in from two different eBay sources. In working with the domestic S90 a few months back, it was apparent that Honda had changed the lever brackets and levers during production and that the CL90 seemed to have levers that were either later version S90 parts or other references to ones from the CD/SS/CL125A models. The CL90 levers are sized right in between the small S90 early style and the full sized levers used on a 250-305cc machine. The right side brake lever was correct, but the clutch lever was the early, smaller S90 type and was too small to fit. Digging around the shop yielded the “wrong” lever, which had been ordered for the domestic S90 bike and it was for the left side, so problem solved, there.

Removing the carburetor and air filter assembly, it was apparent that the air filter connector tube had been misaligned and not fully fitted to the air filter end for many years. The rubber was hard as a rock and distorted on one end, rendering it useless for reinstallation. The carburetor looked pretty clean, as if someone had kitted it once before, but the jetting was #75 main jet and #40 idle jet, with a float level at about 23mm.

The Honda Book of Knowledge states two different calibrations, either #85 or #88 on the mains and #35 or #38 for the idle jet, both uses a 19.5mm float level. I can’t imagine that bike running well on the jet settings that were found today. I hope there are not too many more surprises awaiting me. I did find a squashed wire to the tail light, trapped behind the incorrect tail light bracket installed. The bike had a pre-68 tail light installed on a damaged bracket. The bolt pattern for the brackets using the later “oval” tail light have a reversed bolt pattern where the mount on the rear fender.

Right after I ordered a rare NOS muffler heat shield kit for $150, my friend, Ron Smith, informed me that he had a spare, used heat shield for a CL90, plus a spare entire muffler assembly! I met up with him, nearby an appointment I had made in La Mesa and he gave me the parts. The heat shield looked correct, but the muffler was “sort of alike” but not quite. The heat shield was about the same size, but had fewer mounting holes and the rear baffle was welded into the end of the pipe. It also had a raised bracket on the rear, which was unlike the CL90 part. Further investigation proved that the muffler was actually for an SL90 instead. I think the NOS heat shield kit is really too good to put on this bike, so will probably be resold or kept as an enticement for a buyer in the future.

A new battery was procured and is awaiting my attempts to repair some paint damage on the Candy Red paint scheme. Finding a close match to the red hue at O’Reillys I used the battery cover as a test bed. Although the color is called “Inferno Red metallic” it came out more like a top coat of red, failing to cover some underlying primer. The next try involved laying down a coat of silver, then red over that. The color came out close to OEM, but it flattened out, perhaps due to the outside temperature and humidity just before a rainstorm arrived. The battery that was removed had a sheared-off vent connection, so battery acid was liberally coating the inside of the frame’s battery box area. A combination of some battery acid neutralizer spray and a little sanding had the damaged area prepped for some color.

The battery cover test part came out better with the silver base coat, but it was cold and damp, so the final gloss was on the flat side. The color match seemed pretty close, however and I went ahead and shot the silver/red combo on the frame’s battery box area and just beneath, once I had removed the exhaust pipe and taped off the bolts and the top of the engine cases. A few quick squirts here and there left a much improved frame appearance for little money spent.

The installation of the carburetor/manifold combination was complicated by the usual “stripped threads” scenario that is generally found on most of these bikes. I couple of Heli-coils made things better and the carb mounted up securely. With some OEM Honda 5.5mm fuel line the bike was nearing a light-off status, but when I went to install the battery, a 6N5.5-1D which was recommended by numerous listings, but is not correct. The right battery is a 6N6-1B, which is an inch smaller/narrower.

2-12-14 Updates:

With a new, freshly charged-up 6N6-1B battery in place and the ignition timing set back to the F mark (instead of about 15 degrees AFTER the T mark), the bike fired up on the 2nd kick. The carburetor throttle cable boot covered up the fact that the cable adjuster had been turned out about a 1/2” inch, which kept the idle speed up way too high until adjusted. The valves had been readjusted to the .002” settings and the points cam was lubricated with point cam grease. The ignition plate was a DENSO make, but the points were apparently Daichi brand replacements. Once the gap was reset to the .012”-016” range, the point plate was moved around to allow correct timing at the F mark.

When the intake system was disassembled, the rubber boot which connects the carburetor to the air filter was hardened and deformed into a D-shape on one end. With nothing left to lose, I pitched the rubber boot into the gallon of Berryman’s carb cleaner and left it there for three days. I expected it to come out all gooey and softened, but the extended bath in carb cleaner seemed to have had no effect whatsoever. The part was rinsed in water to neutralize/flush out the carb cleaner. I pondered what would happen of the rubber boot was heated up with a heat gun. With the gun up on the HI setting, the deformed portion of the boot suddenly began to soften and become round again! After a few moments I picked up the boot and it was toasty warm and suddenly very pliable again! I hustled it over to the carb and air filter spigot and eased the parts over both ends, allowing it to cool back to room temperature. Miraculously the rubber boot was tightly fitting to both component ends, much to my surprise and delight.

Fortunately, the electrics were all working fine, once the battery was installed. All that is missing, at the moment, is the tail light. A correct “oval tail light” bracket was ordered from a vendor, but the only complete tail light assemblies for sale are either $80-90 here in the US or about half of that from Asian eBay sellers. Most of them are all reproductions of the original parts. I do have a nice solid early style tail light bracket from a CB160 or CB77 which could be installed with the tail light that came with the bike, as received. It isn’t correct for the chromed fender bikes, but it will work for now, as soon as the squashed tail light wire is repaired.

A quick three minute test drive around the neighborhood brought back a flood of memories of my first CL90, back in 1967. In that moment I felt like I had “Come home again” making the full circle from the beginning of my motorcycle adventures to the present, some forty seven years ago. With only 4600 miles showing on the odometer, it appears that this bike will offer years of reliable service, as they are known for, because of the HONDA name. Good fun!

Bill “MrHonda” Silver

Advertisement