Two Stroke Motocross

Two Stroke Motocross Forum => Technical => Topic started by: MetalMike1982 on February 22, 2012, 05:58:20 PM

Title: 2003 rm125 gearing
Post by: MetalMike1982 on February 22, 2012, 05:58:20 PM

Hey everyone I have 12/49 gearing on my bike . My issue is that it dosent want to stay in the powerband when running down long trails wide open , basically it seems boggy on top when shifting through  the higher gears . The topend is fresh with correct compression and the powervalve evidently isnt adjustable on my bike so Im turning toward changing the gearing a bit . Im thinking of a 51 or 52 on the rear and leaving the 12 on the c/s . What are some opinions ? Should I leave the rear a 49 and get an 11 for the c/s? Ive been told that 1 tooth on the front equals 3 on the back Is that correct?

Title: 2003 rm125 gearing
Post by: beaner on February 22, 2012, 07:01:22 PM

1 tooth on the front equals 3 on the back if your final drive ratio is 3-1. Your is 4-1, so 1 tooth on the front would equal 4 on the back in your case.

Title: 2003 rm125 gearing
Post by: TMKIWI on February 23, 2012, 05:56:22 AM

12/49 is standard on your bike.
On an open trail that should be fine.
I would go up on the rear before the changing the front.
I don't like small front sprockets because they wear to quickly.

Title: 2003 rm125 gearing
Post by: SachsGS on February 23, 2012, 03:12:54 PM

X2. You should never go less then 13 teeth on your countershaft sprocket.

Title: 2003 rm125 gearing
Post by: MetalMike1982 on February 23, 2012, 03:59:28 PM

Quote from: TMKIWI on February 23, 2012, 01:56:22 PM

12/49 is standard on your bike.
On an open trail that should be fine.
I would go up on the rear before the changing the front.
I don't like small front sprockets because they wear to quickly.

Yeah I ordered a 51 rear and I'm gonna leave the 12 on the front for now and se what that feels like . I should have given a better description of long open trails because they are mostly whooped out and sometimes going uphill and whooped out so i geuss Im just asking to much of my 125 . Either way I figure the new gearing should make it easier to smoke 4 jokes on the track .


I'm also thinking of doing a motor upgrade to get some extra power . I know the 144 kits are supposed to be boss on the rm's but Im not looking into spending a bunch of money on the kit .

Title: 2003 rm125 gearing
Post by: msambuco on February 26, 2012, 02:43:15 AM

Where in FL are you riding, Croom?

Title: 2003 rm125 gearing
Post by: MetalMike1982 on February 27, 2012, 01:05:34 PM

 yeah croom , Tanglewood , and Dade city . Are you in FL ?