Questionhi 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
AnswerTerry, 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
