klx351s 140/80 rear tire 43 tooth rear sprocket, 14 tooth front

 

That's odd. I'm running the same sprocket set you are and my RPM and 62MPH is 5400. With the stock 14/39 I get 6000RPM. I wonder who's tach is off?

Could there be a difference in the gearbox ratio between the 06/07 (mine) and the 09 and beyond (yours?)? I seem to recall something changing in that regard.

 

OK, just did some research. Our sixth gear ratios are different. The 06/07 is .904 (19/21) and the 09 and newer is .952 (20/21).

Order-up some gears and you can cruise with more MPG

 

14x45 BB 350 w/ fcr35.

 

Tremor38, I have an SF which has a 17" rear wheel. Smaller OD.

When I had 14/39, I could lift the front wheel in second. When I went to 15/39, That went away.

KLX351

 

I've got the 13/42 right now on my 2006 klx 351s. It seems to run out of gear too fast though. I want to drop the rear to like a 39 or a 40 but I don't want to loose my bottom end and throttle wheelies. Thoughts on this?

 

I have a D-Tracker which also has 17" F/R wheels. What I tried to explain in the last post is that our ratios in sixth gear are different, since that changed for the 08 and later (I have a 2006). That's why we have such a difference in RPM at 62mph.

We've had the motard version here in Japan long before the SF came out.

 

'09 s, 351, tm36, stock tires and rear sprocket, 15 front sprocket. I'm about 165lbs. Lots of power for climbing off road stuff as well as enough top end that the tires become unstable. Cruises easly at 75mph. It gets 48-52 mpg. What more could I ask?

 

Where in the world did you guys find anything lower than a 45t rear sprocket? I looked on BikeBandit and Rockymountain and the lowest that they had was 45t. Of course I could go with the 42t stock but that's what I have right now.

 

What is stock on a '09 SF?