Sebastian, your English beats my High school German by a long way! I assume that when you are talking about + or _ .002" you are referring to ET49, the half-time pinion on the crankshaft. ET 48 was never issued in sizes and always has backlash, presumably to avoid stress on the magneto bearings. There have been some astonishingly good technical articles written about half-time pinion sizes if you want to spend a few long winter nights going insane. What I generally do is get two new 1/8" drill bits and a micrometer to do a comparison on sizes by measuring across two opposite tooth spaces. I never trust what is marked on the pinions. If there was a way to give 4 to 36 degrees advance it might be better if your "Benzin" is as bad as the stuff in Australia. Good Luck and keep at it! Cheers, F5AB/2A/7945 since 1970
HI,
appart from ET49 the half time pinnion having five key ways cut in it, and the face markings ,ET 49 andET 48 are the same. THere fore their is no reason why an oversize half time pinion should not be used as the breather pinion, eliminating that infuriating backlash that always seem to be there between the A.T.D. pinion and the breather pinion.
Thats what we did on Rogers Twin, and what I will do on mine the next time the timing case cover is off.
cheers stumpy lord.