[rsheidler]

Tommy's team response per RoadracingWorld

Deburring around the valves is the issue. They say it is not a performance enhancement, but it it is not, I question why they would do it.

Cheers

Bob

 

[rsheidler]

You can machine the gasket surfaces of the head and cylinder, including the cylinder base. You can (I believe) do multi-angle valve jobs provided that the grinding is limited to the valve seat itself. All engine parts must be stock, with no modification. Carb rejetting/EFI reprograming is allowed, exhaust system can be replaced, shocks can be replaced and fork springs, valving etc can be modified.



I believe the rules are on the AMA web site but I was too lazy to find the exact link.