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Finger trouble?

Posted: Sun Aug 24, 2014 4:24 pm
by Tzen
Ok, got a weird one - my Electra has 32mm Amal, unrestricted down pipe and short silencer, also has hosts TCI unit. To all intents it runs great, nice stable tickover, and much stronger top end. However, occasionally, at fairly high power, it will appear to 'stutter', and lose power. Sometimes barely perceptible, but definitely there. It is very similar to going onto reserve, but not as marked. I have tended to switch to reserve, which after a short while seems to solve it (coincidence??). Today it happened on a return journey from Little Gransden airshow, but I knew there was still a good half tank left, still did the reserve thing, then switched back to normal ON. After a few miles it cleared and went back to normal. Could this be something as stupid as me not positioning the fuel tap properly! I note the ON is not straight down, but slightly forward...could it be this simple, or has anyone any other ideas...As ever appreciate the wisdom of the forum users!!!!!! By the way, this is a brand new carb with fuel filter fitted so doubt the jets are blocked. Have noticed the paint flaking on the filler neck though...

Finger trouble?

Posted: Sun Aug 24, 2014 4:57 pm
by Gwilly
I suppose its possible that the filter in the tank is partially blocked, try disconnecting the fuel pipe from the carb and place the end into a glass container.

Turn on the tap and try and draw off at least a litre, looking for a continuous flow.. If the flow slows down then open the fuel cap ( possible blocked vent hole in the cap) if it doesn't increase the flow then remove tap and clean filter and tank..

Finger trouble?

Posted: Sun Aug 24, 2014 6:41 pm
by Frank
Small world Tzen, an excellent show. You didn't happen to be sitting near the Crow's Nest did you? That would be too much of a coincidence!

Finger trouble?

Posted: Sun Aug 24, 2014 7:19 pm
by Norm
I get that fuel flow problem from time to time on various bikes, not really sure why, possible airlock in the hose, not sure why switching to reserve would clear it but it seems to work

Finger trouble?

Posted: Sun Aug 24, 2014 8:10 pm
by Tzen
Thanks Norm, I thought hose air lock also, in fact I have now repositioned the fuel inlet to the carb to use as little fuel pipe as possible, without undue bends...will also check vent in tank cap and dismantle and clean the fuel tap. Frank, very small world indeed, I was stood right opposite the crows nest against the orange net barrier! Great show, but needed more catering and the beer tent queue was far tooooooo long. Must say I got something in my eye when the Lancasters flew over, what a sight and sound that was. Being an ex RAF aircraft engineer (25 years) what can I say....

Finger trouble?

Posted: Sun Aug 24, 2014 10:05 pm
by Frank
You must have been but a few feet away from me then! I'm afraid the queue for the toilets was enough to persuade me a beer might not be a good idea! Yes the Lancs were the star of the show no doubt but the Mustang with the wind whistling through the guns was a sound to savour but I think they were Merlin powered too. If only the Enfield could sound so good.

Finger trouble?

Posted: Sun Aug 24, 2014 10:09 pm
by Beezabryan
Hi Norm only had that occur once & that was Triumph T100R Daytona that I have the use of when visiting US. It was bloody menace, eventually a new paImageir of carbs was the answer, now runs very well -

Finger trouble?

Posted: Sun Aug 24, 2014 10:17 pm
by sofiaspin
What jets do you have? I would suggest it points to a need for a larger main jet to supply more fuel when the throttle is fully open. Had the same issue on a mark 1 amal 30 with open carb and bellmouth, and open pipe. Not enough fuel at the high end. It would stutter and cut out, once on the outside lane of the motorway. Make sure the needle is set high to allow for a richer setting up to three quarters throttle. You have a big carb there, need to ensure fuelling is consistent.

Finger trouble?

Posted: Sun Aug 24, 2014 10:42 pm
by Norm
Hi Bryan, my CB750 Honda has done it a couple of times over the years and occasionally my VFR but that is strange because it also has a fuel pump

Finger trouble?

Posted: Sun Aug 24, 2014 10:57 pm
by John M
Make sure the vent in the fuel cap is clear.