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nc30 holds revs

Posted: Mon Jun 16, 2008 12:58 pm
by randallbass
hey guys when bike starts its runs on 3 cylinders and fires occasionly on the 4th (1st cyl).
the jets are all clear, floats set, and pilot screws all set to 2.5 (what they were when i checked them)
the bike revs fine, when its warm though it seems to hold revs and then will drop after a while or when i smuther the exhaust for a bit the revs drop back to idle (1800 rpm, track bike!)

i am thinking that its running a bit on the lean side and when its warm it is more noticible so i was thinking of tweaking the pilot screws?
is this right?
when i adjust one do i have to adjust them all the same?
whats the usual adjustment, 1/2 a turn or 1/4 turns?
cheers guys Tim

Re: nc30 holds revs

Posted: Mon Jun 16, 2008 1:26 pm
by randallbass
oh the throttle returns fully and i am pretty certain the carbs are fitted correct and theres no leaks :)

Re: nc30 holds revs

Posted: Mon Jun 16, 2008 11:05 pm
by chrisxr
if there is no leaks try adjusting the pilot screw to 3 maybe 3 1/2 turns it wil stabalise it then adjust the idle to suit you may have a faulty idle circuit a small blockage in a pilot circuit etc this will cover up that

Re: nc30 holds revs

Posted: Mon Jun 16, 2008 11:06 pm
by Cammo
The pilot screws will be open too far.

2.25 turns out is standard, you'll be wanting about 1.5-2 turns out (hrc setup manual suggests 1.5 turns out).

This will muck up your low rpm fuelling though, you might need to change pilot jets if they're standard (#35).

Re: nc30 holds revs

Posted: Tue Jun 17, 2008 12:02 am
by chrisxr
richening up the pilot adjustment will stabilise the revs and stop them hanging on covers a multitude of sins i sometimes set them to 4 turns out to cope with ill balanced carbs initial pick up is rarely compromised in doing so.

Re: nc30 holds revs

Posted: Tue Jun 17, 2008 10:58 am
by randallbass
hey cheers for the help i took the carbs off made shore all the jets and passages where clear and float heights were right then adjusted the pilot screws to 3 turns out from their seat.
She now fires on all 4 cylinders :) thanks alot fellas, i still havent warmed it up fully to see if it has solved the problem of it holding revs (getting a bit late and would be to much noise for my neighbours :P) i will test this tomorro ;) if it still does hold is revs do u reckon try another 1/2 turn out?
cheers Tim