[Badfaerie]

I'm not going to argue your observations, but I will tell you this. If you have a different RPM range, SOMETHING is different. If you changed the sprockets, the most likely suspect is the sprockets themselves. There's no way the bike can just decide "now that I have shiny new sprockets, I'm going to run differently"

[dano68]

Something had been changed. If you are so sure the sprockets are the same, count the links on your chain. But I would have to agree that your sprockets are your problem(not the same as origionally installed).

[steves]

Links in the chain shouldn't have any impact, unless of course the sprockets are different... which is really the only thing I can think of... short of unrelated dirty carbs causing RPMs to rise, or the clutch slipping causing RPMs to rise.

[rider65]

I will recheck everything. It's a real mystery for me.

Is it possible that I break something when I loosen or tight the front sprocket nut ?

[dano68]

Links in the chain shouldn't have any impact, unless of course the sprockets are different... which is really the only thing I can think of... short of unrelated dirty carbs causing RPMs to rise, or the clutch slipping causing RPMs to rise.

I just wanted him to count the links .

If no issues were noticed before you changed your chain and sprockets, I would say sprockets.

[Badfaerie]

I will recheck everything. It's a real mystery for me.

Is it possible that I break something when I loosen or tight the front sprocket nut ?

I would say it is very unlikely that you broke something and the only change was a difference in RPMs. If you broke something around there, you are more likely to see more severe problems, like the bike not moving at any RPM.

The circumstances you describe is the text box example of what happens when you change your sprockets out with those of a different tooth count. It would take a series of increasingly unlikely individual problems all showing up at the same time as each other and at the same time as the sprocket change to come close to causing this otherwise.

[rider65]

It would take a series of increasingly unlikely individual problems all showing up at the same time as each other and at the same time as the sprocket change to come close to causing this otherwise.

It's unlikely but possible so...

Like I said, I will check everything once again : Previous and current sprocket size. I will post picture of them.

I will also change engine oil. Maybe this will have an effect on the clutch and/or transmission.

Stay tune for update.

Thanks all for your input.

[crazycraven420]

the clutch slipping causing RPMs to rise.

that was my thought too.

what oil are you using?

[steves]

A slipping clutch wouldn't be happening all the time, and only in 6th gear at a specific speed.

[rider65]

that was my thought too.

what oil are you using?

I don't know. Same oil since i bought my bike 2 months ago. I plan to change oil for the winter storage coming soon but I will change the oil/and filter today or tomorrow.

[rider65]

Update : old sprocket

Here is the picture of the old sprocket. I will post the picture of the new one this after noon. As you can see it's 15 front, 45 rear.

[rider65]

See first post for solution...

[41 Redhawk]

And that is what I was going to suggest!