Forum

[connieowner]

Hello chaps, gradually with your help getting Connie running smoothly. The most annoying trait of my bike is the surging I get when keeping the throttle constant, the engine seems to want to surge or hunt. Could this be a carb problem? I have double checked the timing/points etc and that seems to be to spec. Recent top end rebuild, new plugs etc. Contact points all good. Whadya reckon? Carb is the only thing I haven't touched only because in my experience that's normally the last thing to worry about.

[Mark M]

Hi, couple of questions, what carb is it and how old is it? Is the tickover uneven when stationary? It does sound like a crab problem...

REgards, Mark

[Gwilly]

The temptation is strong but i'm resisting......... LOL.

Have you tried the local pharmacy?

[ric]

Sounds like it could be a weak mixture - you haven't converted it to EFI have you

[Leon Novello]

Sounds like it is starving for fuel.

[Bullet Whisperer]

I would try lowering the needle[s] a notch in the carb[s], that sorted my Trident when it rode like that. Regards, Paul.

[Mark M]

Gwilly, l just read what l wrote. Ooops! Mind you l've had a bike previously infested with mice so crabs (of either sort) isn't such a stretch!

REgards, Mark

[connieowner]

hi guys,, well this must be a record but it has taken me a full year to reply to your kind responses..a few days after I posted this I had a bereavement which has meant life has only returned to normal recently and back out on the bike again...

Mark M - it is the monobloc su carb if that makes sense, year is 59. In addition to the problem as listed in my first post, other symptoms are; tickover is a little lumpy when cold and as the engine warms up the engine does not return to a steady tickover but idles quite high, if revved a few times it settles down. When I back off the throttle when slowing down it feels as if the engine is still running on and therfore I often end up pulling the clutch in and using the brakes whilst waiting for the engine to slow...hope that gives you enough info to help me with diagnosis?

thanks

[Mark M]

Sorry to hear that. I hope getting out on the bike helps a little. From your description I think your carb slide and probably body is worn. I guess you are saying it is an Amal Monobloc? SU is a different manufacturer and rarely fitted to motorcycles as standard. Have a look on the Amal Carburettor website to identify what you have. New carbs are not very expensive and if there is a suspicion of wear in the body I'd just replace it. This is one of the most critical devices on a bike, even small carb problems can really mess up the whole riding experience so it's worth getting it right!

REgards, Mark

[Biscuit Barrel]

I had what sounds like the same dealy when I fitted screamin eagle slip ons and dynojetted (stage one) my Sportster. 30 to 40 mph on a steady throttle it 'hunted' or surged. Hard to describe, you described it better. It was almost unrideable at 30. Opening the throttle it pulled cleanly and a steady throttle above 40mph it ran fine. Turned out it was running lean on the needle. Raise the needle a notch (lower the clip) and try it. If that's not cleared the problem try one size larger pilot jet. Go up one step at a time and alter one thing at a time before trying it.