When I bought my bike a few months ago it came with the 48 tooth Vortex rear spricket on it, I'm wondering how out will my speedo be? Thanks

 

I recently went down 1 tooth up front and up one in the back. went on a ride with my buddy, and at the end, his speedo(stock gearing) had put 26.1 miles while I had like 27.6 or something... I forget exactly...

Basically, we drove the same distance but my odometer logged about 6% more than his. Also consider that while his is stock geared, his is probably a couple percentage points high anyway...

So I figure that I am about 10% off. So my top speed went from probably 155mph down to 140mph, but I got lots more torque so it is worth it.

 

try this:
http://forums.cbrworld.net/forums/11033/ShowPost.aspx

 

I just had my F4i retuned on a Factory Pro Eddy Current Dyno. I did the 15/47 regearing, and the top speed on the Dyno was 139mph, while the speedo registered 161mph.

So at top speed my speedo is roughly 20mph off, or about 15%, which is huge.

So when I drive 100 miles, my odometer is gonna log 115 miles. I do not mind losing top end speed because I feel that 140mph is still fast and I picked up quite a bit of useable power, but I need to get a speedo-healer and install it so that I do not rack up too many false miles on the odometer.