I recently purchased a 77 Bonneville that had been sitting for 8 years. Had the carbs rebuilt and now starts and revs freely on center stand. while riding, bogs down at 4,000 rpm then revs freely after that. Gas or electrical?
I rode at a stready 4K to see if it would free up, but really started to break up at lower rpm's also...that's why I'm thinking may be electrical...like a coil. Barely made it home. Thanks for your thoughts
If the jet was clogged (which is what I think is the problem), any idea why it would it still rev up freely on the center stand? tks.
On the stand there is no load on the engine. I assume it revs on the move if you pull in the clutch? Have you cleaned the tank, petcock and fuel filter? The engine will rev freely requiring little fuel and light throttle opening with no load but under power you may have fuel starvation from clogged lines. Equally, it could be electrical from coil breakdown to insulation failure of the HT leads. The latter would provide a spark show at night!
I just had the carbs rebuilt and new fuel lines put in...but we didn't clean the tank. Probably a mistake. First ride was problematic. I'll check the coils (2 6V). Interesting while riding, it will get past 4K then rev up with no problem. Is there a jet that handles the 4K range and then another jet takes over? Tks for your help.
Those symptoms can sometimes be a blocked fuel tank breather, if it breathes through a vent in the cap check it’s not blocked
this cap was leaking, even with a new gasket, so I just ordered a new one. that's a new one on me. I'll also try pulling in the clutch and see what happens like someone suggested. thanks so much.
