Hi wobblywalrus,
Yes, I know Alpha Bearings, they have done work for me in the past, mostly obsolete crankpins or rod races.
I have done quite a few Harley Sportsters and K/KH cranks in the past, always used the race shop 50 % of the reciprocating weight rather than the there about std 60 % the factory use on their street models.
The race 50 % factor on these V twins seems to push the dreaded "around 4500 rpm" vibration out of the available rev range, so I like it, but I'm not sure at all it'll be the same factor on a single!!!
I'm not too worried anyway, as I said, I don't know the balance factor, but I do know the weight I've taken out as lead!!!
I might spend tomorrow weighting all the bits of the crank assembly, and then, I can have a go at calculating the factor they used in them days!
Thanks again,
Patrick