78 GS550 Blowing fuel vapour back out carbs.

[GS550_MATT]

Exhaust
1 2.65mm shim
2 2.60
3 2.60
4 2.65

Inlet
1 2.70x
2 2.75
3 2.75
4 2.75


Because the cams are touching the shims and there is no gap I assume that fitting thinner shims will bring me to 0.05mm clearance, or the next size will be 0.010mm, before I buy them should I set them at .05 OR .010, Specification is 0.03 - 0.08.

Im not sure if its best to fit them at 0.05 or 0.010 , im tempted to go 0.010 because as the engine gets arm the clearances actually get smaller.

 

[Guest]

Fitting a .05 thinner shim will not necessarily get you .05 clearance, because you have to allow for the valve spring tension. You could fit a .05 thinner shim but only end up with .02 clearance. You could take your thinnest shim and move that around the buckets to try to get definitive clearances, and then calculate from there.

In general terms, the higher end of the factory approved range (0.03 - 0.08) is better, because, as you say, the clearances will decrease. In practice, 0.10mm (not 0.010!) will be fine.