11-05-2022, 11:33 PM
The shim under bucket tend to be the smaller shims, ~7.5mm and shim over bucket the older ~25mm. Shim over bucket had to be the full size of the bucket for the cam lobe to act on. By sticking the shim under the bucket you can use a smaller diameter shim as it is now just a spacer and the bucket is directly acted on.
So now there is less weight reciprocating up and down in the valve mechanism and you can rev the engine higher (if required and dependent on any other restricting parameters). But I would have been very happy with shim over bucket as our engines are not particularly high revving.
Some alternative engine designs are well thought out. The Kawasaki W800 uses smaller shims which you can directly access by sliding the rocker arm on its shaft. A nice solution for another low revving engine.
The good news is our clearances seem to hold up very well according to this forum users' experiences.
So now there is less weight reciprocating up and down in the valve mechanism and you can rev the engine higher (if required and dependent on any other restricting parameters). But I would have been very happy with shim over bucket as our engines are not particularly high revving.
Some alternative engine designs are well thought out. The Kawasaki W800 uses smaller shims which you can directly access by sliding the rocker arm on its shaft. A nice solution for another low revving engine.
The good news is our clearances seem to hold up very well according to this forum users' experiences.