Multivars have a smaller OD shaft.
Stock:
Diameter = 1.340"
Circumference = 4.210"
1/2 stock circumference (approx belt contact) = 2.105"
Multivar:
D = .825"
C = 2.592"
1/2C = 1.296"
2.105 - 1.296 = .809"
so theoretically you have almost an extra inch in your belt for the multivar.
you either/both bring the belt in (shorter belt as you have done) or swing the motor out into the belt run. I don't think you can top out on the polini spring, but you can top out the nut/bolt that goes through the stock spring - preventing full extension -- until something hits, like the motor mount stop, or the head on the frame, carb on swingarm etc. so you could take off the belt and see what is preventing it from swinging forward. but if it works, it works. there is no spec position.
> LSLB RXb wrote:
> -------------------------------------------------------
> is this with a stock length conrod or the longer conrod cause 1.3mm btdc
> would be different if it was the 75mm conrod vs the 85mm conrod.
rod length should not affect timing in a significant way.
http://www.torqsoft.net/piston-position.html
crank angle difference between 75mm and 85mm rod with 40mm stroke @ 1.3mm btdc is .23 degrees.
piston position difference @ 18.5 deg is 1.302mm - 1.271mm = .031 mm aka .0012"