Ok, I took my bone stock KLX (600 miles on it) and just changed out the front sprocket to a 13t and it actually increased top speed. I used a GPS and the same stretch of road. It was a flat road with curves at the beginning the about a 1.25 mile straight at the end. With the stock gearing (14t) it could only managed 77.5 MPH when I changed to the 13t front it went 79.4. I made three runs with each and used themax speed on my GPS to get the results.

The 13t is faster because it lets the motor get into a better RPM range in 6th gear. With the 14t the bike just won't pull enough RPM's to reach a high speed. The 6th gear is more like an overdrive. I tried 5th and 6th for the 14t top and it went fastest in 5th gear. I know if you go down a long hill it would go faster but it won't keep it when it flattens out or goes up hill.

Next I will try the 45t rear to see what it will do on the same road.

Keep in mind that this is realGPS top speed, with every run the speedo was readingalmost 90 MPH!

Here is the 14t



Here is the 13t

 

What was your RPM going 79.4 mph with a 13 tooth sprocket?

 

I wish I kept up with that. It still would not reach max RPM's and it still slows down going up hill. I will take notes when I do it again for the 45t rear comparo.

 

I would try it with mine, but I am afraid of blowing my engine up.The dealer had told methathighway speeds for a period of time is badfor this bike. I wonder if sustaining 60+ mph, is that bad for the bike. If so, I bet it is worse for it with a 13t sprocket.

 

My opinion is that long periods of highway speeds will not effect the bike. It is sold as a "ON" and off road bike which is backed with a 1 year waranty. Kawasaki would not sell a bike that is expected to be ridden on the road including highways that will blow up making them have to spend there money to repair it under waranty. Don't forget that the same bike is sold in japan in supermoto form.

 

Well I think that the bike is running low enough RPM's even with the 13t front and not bogging as bad with the lower gearing. I don't sustain speeds above 70 MPH for long runs but I don't think it will hurt it. If it does I will take it back for warranty work. It is a lot harder on a bike bogging it up a hill in too high a gear or hitting the rev limiter and holding it there than running down the road for short burst at 70+ without even reaching max RPM's.

 

EvildoerZX10R, what were your numbers for the others runs?

 

Not really sure because I didn't have the max speed displayed during the runs. I did check it at the end ofeach run but don't remember the exact numbers. I know the first run on the 14t was the fastest for that one because I never moved the max speed up on the GPS. The second run with the 13t was the fastest for that one. They were all within a couple of tenths or so.One thing I noticed later was the 13t holds the speed better goingup and downhills.

 

Go back to your dealer and tell him 'blah, blah, blah!'[sm=icon_blah.gif][sm=bs.gif] I've put over 10.000miles on mine so far at 'highway speeds' and don't have a hint of trouble. Of course, my sustained speed never goes much above 60-65MPH.[8D]