I was wondering if anyone had an opinion about a 12t/43t sprocket set-up for the raptor. My brother-in law is a Yamaha Rep, and he's been told that this seems to be the best combo. Any opinion or advice would be great.

 

here is a gear ratio chart.

12/43 is very low.

 

That is the ratio that I am running on my Raptor. The 12 tooth was fine until I went to 22in tires. The 43 brought it back down to where I wanted it for mostly trail riding but beware if you do this with stock tires your front tires may never be on the ground again [img]i/expressions/face-icon-small-happy.gif[/img]!

 

Whitebelt
I have a 12 tooth and a 42 tooth. Works real good.Lost some top end but thats ok. Great for the trails.You do not use the clutch as much.
With the 42tooth rear it still fits on prm skid without any mods.