I think the 1.507 bar is the bar that we should be using on all our 07-10 sleds and here is why.
in 04-05 the zr900,m-series&firecats had 8.5 inch primary clutches with 10 secondary clutches and they called for the 0644-427 1.655 bar
In 06 the firecats/zr900's went to a 8.25 primary and a 10.4 secondary and they call for the 0644-496 1.507 bar
In 06 the crossfire/m-series had 8.25 primarys but still used the 10" secondary so the 0644-427 1.65 bar was still recommended.
But from 07-10 the primary and secondary's are the same sizes as the 06 Firecats/zr900 so why would we still want to use a bar disigned for differant size clutches.
The chassis has not bearing on proper operation of clutches and there need for correct offset.
I have to believe Arctic Cat has been trying to address bely failure issues and they now recommend the 1.507 bar for all the 2010 models. And since my clutches are the same as a 2010 models I have to believe the best choice would be the 1.507 bar.
