Hi guys, this thread is really great, agree with w8wye and also agree on the harmonic vibrations issue - if you are unlucky your modified engine may well turn out to vibrate excessively at your normal operational rpm and that is hard to calculate in advance I guess - hence Clarence Lees note on trial and error - he should now..!
Holeshot , yes I think you are right that shaping the crank should decrease "oil mist resistance" somewhat, wonder if the effect can be measured..? I have not tried measuring but still do shape cranks as shown on attached pic.Feels good at least..!
Bill Robisson , I was intrigued by your explanation on piston acceleration and my subsequent question is the following:
What limits the possibility to lighten the con-rod, is it tension or compression/bending that will normally break it...??Same thing for 2- and 4-strokes..?? Conrods in titanium were available some years ago but I have not seen such ads lately.
OK guys, sack time in Sweden now........Cheers/Harald