carb sync

[Guest]

Fellas
just had my CV carbs cleaned and refitted, I hooked up the vac gauges so as to balance them, when I try to get the engine a 1500rpm by adjusting the idle screw it always revs to 3000 or more and i have to unscrew it back down to 1000 or below and will tick over ok ,but cannot get a reading at that low rpm,
I can keep the throttle at 1500 or about but have to be moving the twist grip to keep it there, which makes balancing difficult,
I have a dynatek 2000 ignition system on it and the advanced curve is at 4 and ignition st at 37-40 deg as specified by the instructions,
any Ideas
mark

[tom203]

Did you do a good bench sync so all the throttle plates are open the same (they will appear practically closed) ? this should give a stable idle for the vacuum sync

[bsa44161]

carb sync

yes , used a wire brush strand

[tom203]

OK, what about air leaks- carb boots, o-rings at head interface, etc.? and put your bike/model in your signature.

[azr]

There's no reason why you can't do your vacuum synch at 3000, some guys do it at 5000rpm. It's odd that you can get the engine to stay at 1500 by using the throttle but not by screwing in the main idle screw. I'm guessing you vacuum levels are fairly off when you look at the meter? that or one of the vacuum lines is not set up/working properly?

[850 Combat]

Are there damping valves on your gauges? Sometimes you have to open those up a little for it to read at lower RPM.

[yank]

yes , used a wire brush strand

A wire brush strand might be a little small. Let the experts chime in.

[bsa44161]

carb sync

ok
Ill try to set at 3000, and see if its ticks over better when adjusting stop screw, and yes all the o'rings etc renwed as its just been rebuilt,
Mark