Gearing Ratios. . . .

[Gilmoses]

Trying to understand Gearing Ratios, and where I should begin . . .

The low down . .

1. A basically stock GS1000 motor, with a stock back-cut tranny and 1085 kit. 630 drive chain
2. the bike sits at a 64" wheel base (street bike)
3. I weigh 240 suited up.
4. Trying to set up for 1/4 mile racing.
5. Right now, I'm I have a 15/42 sprocket setup and shifting to 4th gear through the traps. . . Shift lite set to come on @9500 RPM's, never comes on after the 1st to 2nd gear shift.
6. I tried 15/44 setup, also and got pretty much the same results. . .
7. I'm launching @5500 RPM's . . .

Right now I'm thinking about going with a 16 or 17 tooth sprocket, because I don't think going bigger in the rear will do any good. . .

What am I doing wrong ? ? ? Where should I start? ? ?

 

[heathen]

if you want to get the shifts tighter together and want to change the front sprocket you have to go down instead of up. ie 14 tooth front.

 

[rapidray]

On that bike you want to gear it sdo you go across the finish line at 9500 in 5th gear. Try a 15/48, as that will get you in the right area. Ray.

 

[trippivot]

I started with an engine like yours but a 68"W.B. and wheelie bars 14-49 you will go through the traps at redline in 5 gear under most atmospheric conditions . 3.5-1 is a great place to start with mild power and wheelie bars.
3.3 or less for a street bike set up so you wont flip it


gear ratio = driven gear divided by drive gear so 49 divided by 14 is 3.5

14-49 = 3.5-1

14-48 = 3.428-1
14-47 = 3.357-1 my magnum gear I use in cold good air gets me M.P.H.

since you have a 15 front

15-48 = 3.200-1
15-50 = 3.333-1