crankshaft

becks · Post by **becks** » Mon Oct 06, 2008 1:32 pm

can anybody tell me how i can determine if i have purchased the correct crankshaft for my 1959 5oocc model 20 alternator twin . I have been told that all i have to do is measure the opposite side of the crank where the pinion connects to the crankshaft by taking a measurement from the center of the pinion retaining bolt to the outside of where the main bearing seats. If it measures 19mm from center to outer side then its 500cc if it measures 21 mm then its 650. Is this correct and if it is the latter then is there any thing stopping me taking the crank to an engineer who could machine the crank down to 19mm or will this render the crank useless as i have been told that my only other option is to convert the bike into a 650cc thanks becks.