xr650r countershaft sprocket

so i have some motard wheels on my bike but the gearing i have right now isn't good at all. i have a 14-45 setup and from what i can guess it only goes about 70. what is the largest countershaft sprocket i can fit on this bike, and is it bad to run a really large one for any reason...

I have run a 16 sprocket on mine. No problem...

Running a larger c/s sprocket won't hurt a thing as long as it can physically fit without interference. I've never tried or seen a 16t c/s sprocket, but I know they exist.

What size tires are you running? 120/70/17 or ???

...is it bad to run a really large one for any reason...

Larger sprockets actually have some advantages over smaller ones. Larger sprockets run quieter and more importantly they don't wear the chain/sprockets as fast.

Running a larger c/s sprocket won't hurt a thing as long as it can physically fit without interference. I've never tried or seen a 16t c/s sprocket, but I know they exist.

What size tires are you running? 120/70/17 or ???

rear 150/60/17

front 120/60/17

With the 150/60/17 rear and 14/45 sprockets, I would think you should be able to approach the low to mid 90 MPH range with enough straight pavement, assuming there's no serious head wind and your engine is running perfect. Changing the front to a 16t should bump you up past 100 MPH and into the 105 to 111 range if there's enough pavement, no head wind and if your bike is running well. Are you sure you're only maxing out at 70 or so?

70 was my guess with the way traffic was flowing... to give you an example with the bike in stock gearing i would get about 100. now with the 17 inch rear and 14-45 gearing the bike is definately way way way slower on top end. i have to get my digital speedo dialed in to be exact but i was thinking if i held it to the head i would get probably 80. i used to be able to do 70 without the motor really revving. i guess i will have to check back tommorow when i get the speedo dialed so i am not playing the guessing game

70 was my guess with the way traffic was flowing... to give you an example with the bike in stock gearing i would get about 100. now with the 17 inch rear and 14-45 gearing the bike is definately way way way slower on top end. i have to get my digital speedo dialed in to be exact but i was thinking if i held it to the head i would get probably 80. i used to be able to do 70 without the motor really revving. i guess i will have to check back tommorow when i get the speedo dialed so i am not playing the guessing game

Are you banging off the rev limiter, or won't it pull 5th gear?

I've got a 650R with a full SM setup, and a 150/60-17" rear tire. For gearing, I've used 15/46 (which is about the same speed as the stock 14/48 with an 18" tire), but still too stumpy but doable around town and if you don't plan to cruise over 60-65mph. You'll be changing gears every second during acceleration.

Lately, I went to a 16/44 setup which was MUCH better. This gears it to do around ~110mph or so, ~ 80mph cruising. It takes longer to build RPM's, so shifting is less frequent, and the torque hit when shifting on the street is much smoother for you and the tranny. Most SM guys run 15/39-15/42. My 16/44 setup is roughly equal to 15/41.

The difference is that the 16/44 setup will work with the stock 110 link chain (barely, the wheel is WAY back in the adjusters), whereas the 15/41 setup requires a 108 link chain.

Downside is that nobody makes a case saver for 16T front sprockets. What I did was trace out my XR's Only 15T case saver on some 1/4" aluminum. I then cut it out (slowly) with a jigsaw and a metal cutting blade. I drilled my mounting holes etc., then belt sanded the contours of the case saver so that it fit around the chain and the clutch lever arm casting. My 16T actually came out beefier in the thinnest section than the XR's Only 15T I copied. Alot of work, but well worth it for a BEEFY case saver.

On the other hand, if you use real high quality chains (DID ERV2 or ERV3) and use a properly riveted master link, you probably could get away without a case saver. Or you could simply grind out a 15T case saver for the extra clearance, just be aware that the thin section will get even thinner.

I bought my 16T front sprocket from Sprocketspecialists.com.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now