QuestionI bought this sweet little machine from a guy who didn't look very handy, though he did say it had a loss of power. My motorcycle friend who came with me said, "Bet it's the carbs," so I bought it. Carbs were very clean, actually, but went ahead and bought the rebuild kits just to make sure everything was working properly. Power loss is the issue - the bike starts right up, revs just fine, but the moment I get on the bike and click it into 1st gear, it loses power as if it was meant to be a 50cc scooter instead of a real motorcycle. We replaced the spark plugs and checked all the wiring and the fuses. It's so frustrating because it does start right up and revs fine...until putting it in gear. Any suggestions would be greatly appreciated.
AnswerCathryn,
Check all of your wiring connections. See http://oldmanhonda.com/MC/WiringDiagrams/MCwiring.php#class for diagrams and wiring colors.
These carbs have an air cut valve on each carb body and one may have a bad diaphragm.
I suspect that it is only running on one side. Run the engine for a minute or two, then pull the plugs to see if one is hotter than the other and/or check the exhaust header pipes for equal heat as they warm up (caution here!).
The CDI module may not be giving you spark advance, as another possibility. Check it with the engine running and a dynamic timing light connected to the coil wire. It fires both plugs at the same time, so it doesn't matter which one you use.
The fuel tank/petcock/fuel lines all need to be checked for flow. Gas caps can also get plugged vent holes, causing fuel flow reduction.
Bill Silver
