I would worry more about the reliability of the bike when changing internal parts that were designed to work together......plus, some bike it would be like rebuilding the motor to do it!!! For instance, my 600RR has to have the cases split to get access to the tranny.......that means a complete teardown of the motor, for the convenience of riding highway at lower RPMs.

I like FHL's idea better if you can fit a +1 or +2 sprocket up front and have a -1 or -2 to swap out to....if you have the right combo you won't need a shorter or longer chain! I had once thought about getting sprocket specialist to make the 2-peice quick change sprockets for me in 2 sizes, where I didn't have to take my wheele off, but you would have to have 2 chains ready to go at all times and have extra master-links when you wear them down from changing em out.

Or, if you could get good enough to do everything on stock sprockets you don't have to worry about it!!!

 

i've thought about this and posted a thread like this before. I even figured out, by how many teeth, the tranny spockets would need to be changed. I wouldn't change 1st gear; i would change 6th. That gear doesn't take much abuse, and it would still be easier to use the other gears for stunting. So basically what my idea is, is to put a big sprocket on and then change 6th gear for top end and cruising

 

Here's a pic courtesy of Ron Ayers of an f4/i transmission, and the parts list tells how many teeth are on each gear. If Im looking at this correctly, first gear cannot be made any steeper since it's already at the diameter of the main shaft. (part #1 meshing with #4) This is the case on pretty much every bike tranny from what I can tell.

6th gear I think is #15 and #17 can anybody confirm that?

 

Actually Lb3 told me about this idea 2 weeks ago you hacker. ahha

 

yep...

 

if my calculatations are right, and if you could somehow switch the 23t and 26t 6th gears, you could have a +11 rear sprocket and have the stock top speed

 

6th gear on an f4i is 23/27
6th gear on the cracked f3 motor in my shed is 23/25 It seems bikes with 15 tooth sprockets have higher 6th gears, makes sense I guess.
If it fit, that could make my top speed about 8% higher. thats not nearly enough, I'd want more like 15% before it would be worth the effort.

 

if you keep it adjusted it'll always shift into the right gear cleanly and stay there.


but i doubt that kind of system would work very well on a +100HP motorcycle

 

i always had the idea of just making 6th like a huge over drive..then when ur chillin on the highway at low revs and want to wheelie just click down once or twice and get your engine brake back and ez clutch up..

 

+1 to that

 

+1