Hitchcocks Forum

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.

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

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

Have you tried the local pharmacy?

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

Sounds like it is starving for fuel.

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

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

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

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

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.