Help needed - fuel problem

[Andy1970]

Well, the new fuel pump didn't make any difference, so I went onto plan B. Removed the carbs again today, cleaned carbs 1 and 2 again, but also switched the floats, valves and seats between carbs 1 and 2 to see if the problem moved with the valves.

Put it all back together and thank foc it looks like the problem may finally be sorted. Running nicely on all four cylinders, and no longer pissing fuel everywhere.

Weather permitting I'll take it for a short shakedown run tomorrow, which will be the first time I ridden it since last autumn.

[tommyardin]

The bike ran fine with the pump disconnected and a temporary tank plumbed straight into the feed to the carbs.


The pump had been shutting off ok, and it was only leaking when running, but as I've tried pretty much everything else at this point I've ordered a second-hand replacement pump off ebay and will give that a try.


Plan B, if that doesn't work, then I'll have the carbs off (yet) again and give them another clean. I think that the most likely culprit at this point is a valve which is sealing just well enough to stop the fuel at atmospheric pressure, but not well enough to stop the fuel when the pump is running and the engine is vibrating.


If Plan B fails then Plan C is to get the carbs cleaned and overhauled by a professional.

Or a 5 gallon can in a top box plumbed in directly.
Sorry not helpful I know, but would certainly make the bike handle weird with 50 lb weight of fuel up high slopping around.


I notice that BB made a comment about the carb drain screw or screws are the tight and sealed? just sometimes the obvious is easily overlooked.
Good luck and I hope you sort it soon as I'm sure it is trying your patience.


As it only does this while the bike is running could it be to do with a carb fuel shut off valve letting go with the vibration, I think this is called clutching at straws.
As I said 'Good Luck'.