gearing selection for my R

[pantera1975]

I got 2 250R's one stock cylinder the other with TT porting and a psi hi rev pipe. The ported bike had 13/36 gearing and stock is 13/39. If I change the front 1 tooth and run 39 on the back would that be the ratio as 13/39? I want to switch top ends for the summer. Or is there somthing else that I should use for gearing. I'm doing trail riding and with the 13/36 the bottom end is fine for me with the hi rev and porting since I dont really use the bottom end anyway.

[WilliamJ]

Yes that's almost identical.
13/39 = 1 to 3 (Standard final drive ratio)

13/36 = 1 to 2.77
14/39 = 1 to 2.79 - a tiny difference in speed at the rear wheels, maybe half an mph at the top end from the 13/36

But that is raising the final drive from stock giving a higher road speed. Is that what you want?