Motorcycle Repair/cl 77 1965


hi I have just restored a cl77 but haven't touched the engine except new points condenser plugs and carb repair kit. before strip down engine ran sweet but under load did not pull over 1/4 throttle if I eased back throttle  it would slowly start pulling I put this down to parts listed above I have done adjustments to your recommended settings . but problem still exist left hand side is a nice light brown colour on spark plug, right hand plug is brown with black sooty deposit this was best result I could get then next several times I check tried bike out I am getting wet black plugs, but please note no blue smoke out of exhaust pipes  just don't seem to be getting anywhere but today have tried compression test readings are 125 psi each side would welcome any advice  best regards terry from the uk

Terry, if the compression readings are 125 with the throttle held wide open, then either the top end is worn out or the camshaft timing is off a tooth. Based upon your performance problems, overall, then I suspect the camshaft timing is incorrect and/or the spark advancer is worn, loose or has stretched/broken springs. You should verify the ignition timing with an automotive timing light first.

Check the banjo fitting bolts for the fuel lines at the carburetor for plugged filter screens.

Float level settings need to be 22.5mm

Main jets are usually about #130, with #38 idle jets. Be sure that the needle jets are still in place, sometimes they fall out with the main jet holders and not noticed.

Carb bodies should be cleaned thoroughly and all fuel and air passages cleared, especially the ones in the carburetor throat.

Make sure the slides are not in backwards. Cutaways towards the air filters. Reversed slides is a common mistake. Check those first.

Bill Silver

Motorcycle Repair

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Bill Silver


Need help with vintage Hondas from the 1960s? I am an expert with 250-305cc bikes in particular and most all of the other pre-91 models, in general. I do NOT claim to have a great deal of experience on Gold Wings, Cruisers, ATC/ATVs and dirt bikes.


I have owned/ridden/maintained Honda motorcycles for 35 years. I have written five books on Honda repairs and collecting. I was a service manager for two Honda shops back in the 1980s.

VJMC (Vintage Japanese Motorcycle Club) of North America

VJMC newsletter, as editor for two years and as contributing editor currently.

3 years auto shop in high school, teacher's aide in Automotive Technology in Jr. College, Diesel mechanic course in college, self-taught mechanic and automotive writer.

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