carb adjustment

[Sam C]

I've just tried to balance my carbs in terms of air flow (rather than mixture) and discovered that it's basically impossible.

I noticed when I was doing it that one of the pistons sits about 2mm higher than the other. This is the case at idle and then right through the revs as the pistons rise - the right one is always about 2mm higher than the left.

I can't get the right one to drop right down, no matter how much i loosen the idle adjustment screw (with the linkage slackened off of course). As a consequence I can't get the air flow to match on each one at a sensible idle speed - the right one is always sucking in more air than the left at lower idle speeds - it's not until I increase the idle speed on the left one up to about 1400 rpm that I can get them to match.

So why would this be the case and how would I fix it?

Cheers all!

Sam

[greenbonnie]

hi sounds like you have your jet  is set to high. or the needle is not fitted in the piston corectly.i would also check you dont have and damage to the piston locating lug. this would cause the problem you describe. pete

[HMaze]

Hi Sam,

Identical piston springs?
In the case of Strombergs same Piston weight?
Piston and domes same "fall" time?
Both dampers the same? (sealed, open)

cheers,
Harry

[Freek76]

Are the pistons at the same  height with the engine turned off?
No vacuum leaks or worn throttle shaft?

[bob dunn]

i had this on my 1300 spit , i screwed the big nut underneath up on one and down on the other until they were both in line with the carb body , then  clock wise 12 flats . clean plugs , run for 30 miles , check plug colour , if black,anti clock one flat , if light straw ok, if white clockwise one flat .