I just bought a 1988 250R and it is running on 210 pounds of presure(thats what the guy said) so because its running on race fuel I want to run on pump fuel. For the motor it has a Pro Design Cool Head w/(I dont know the cc of the dome) with a Pro Design Adjuster Plate. I was thinking if I was to put a 19cc dome w/bigger gasket would that lower the compresiion making me able to run on pump fuel and what should the timing be at?