(sorry for re-post but this place is a bit busier!) ZXR250 1989 I saw some old threads about people using 7.5mm diameter valve shims, rather than the standard 7.9mm shims... Is this what people are doing ? It makes me slightly nervous that if a valve bounces (at 20k rpm) then the shim may jump under the bucket. Unlikely perhaps but..
Have not done shims so can't really help. Personally if its meant to be 7.9 then that's what you should get. You'll probably have to ring a shim place and see if they have that size. I think precision shims in Melbourne round up and call them 8mm shims. @zixxer you've done shims, what size did you get?
Well all 16 in my engine were 7.9mm but having looked into it a little then I'm going to order (6) replacement shims at 7.5mm. Looking through the old service receipts, it's dropped a valve in the past so I'm suprised that the garage that repaired it didn't think to check and re-shim all the other valves.
