Cylinder not as hot has others

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TwostrokeStu
Posts: 16
Joined: Tue Apr 19, 2016 6:24 pm

Cylinder not as hot has others

Post by TwostrokeStu »

Hi all
My 1976 GT 750 has one cylinder running cooler than the other two any idea what the problem could be, its okay with choke on on start up but with choke off the right cylinder is not has hot I bought the bike fully restored in march this year i have changed the diaphragm but it made no difference.
Hears Hoping Stuart
teazer
Posts: 1035
Joined: Mon Mar 07, 2011 8:10 pm
Location: Chicago

Re: Cylinder not as hot has others

Post by teazer »

It could be a blockage in the pilot circuit on that side. I have a similar issue on a bike on which the carbs were cleaned and fitted with new jets, so they will come off again and see if there is some sort of partial restriction in the pilot passages.

BS40 carbs have a really torturous path for the slow circuit and it's easy to have it partly blocked on the bypass or pilot jet outlets.

When you pull the carbs off, take the time to synch them carefully and set the fuel levels the same on all three.

It's also worth double checking the ignition timing etc, but if it's OK on choke and cool off, then it's probably the slow speed circuit.
teazer
Posts: 1035
Joined: Mon Mar 07, 2011 8:10 pm
Location: Chicago

Re: Cylinder not as hot has others

Post by teazer »

Try replacing the choke plunger. Mine turned out to be a single hard/bad plunger which did not seal perfectly.
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