03 125 gearing for MX

Started to ride MX on my 125, what gearing is recommended for it? Im having trouble getting "up to speed" to clear larger jumps and im getting the R's up plenty so Im guessing its gearing more than it is me. What are you guys running?

Your 2003, I think, has a 13/51, and I can't find any larger rears for sale, so you'll have to drop the front one tooth.

If that's too much low-end, then you'll have to get a slightly smaller rear...

47/12 = 3.92 (stock ratio with different sprockets)

51/13 = 3.92 (stock)

48/12 = 4.00

49/12 = 4.08

50/12 = 4.17

51/12 = 4.25 (may be too much for MX)

You'll notice going down 1 on the front is about equal to going up 4 on the rear, and vice versa.

Edited by ridleyredraider

Im running 52/12..

Hah, wow...then it's not the gearing. Maybe your clutch plates are slipping.

Also depends on whats done to the bike. Still stock? We run the stock gearing and it does pretty good on short & open tracks.

But I'll have to repeat this again, The FMF pipe on his bike made a huge improvement on this bike. We did add Vforce reeds but that only helped a little with throttle responsiveness.

But based on what type of tracks you ride. A closed in, tight SX style track or wide open. Last weekend my son rode a newly designed SX style track on the 250 and the gearing really sucked but it was all in fun so he was just out to ride.

Here's a vid of him on his 125 in that back yard. It's a tight track. But as for the open tracks, he has 6 gears.

Dylan & Kody

Im getting power, its got a FMF and jetted perfectly, zero bog. I know I need a rear tire, but that should not make or break me clearing stuff. The jumps at my local track are much much bigger than that video ^^ with about the same take off area.

A worn tire is part of the problem. You're not gonna do much with less than 75% tread without have traction issues. Alot of our tracks are like you're describing aswell.

1. It's a 125

2. it's gonna take practice sweeping turns faster and staying on the pipe.

3. May want to have 2 or 3 different front sprockets for different tracks.

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