Gearing 125 for sand track

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9/25/2018 1:58 AM
Edited Date/Time: 9/25/2018 2:42 AM

I’ve got a 5spd cr139 that runs pretty strong and with 12/48 (4.00) gearing gets to 5th gear pretty quick. I’m heading to a fairly deep and long fast sand track this weekend.
I was thinking of going to 13/49 (3.77) to keep 3rd and 4th gear pulling longer. I’ll be using a sand tyre too
Is this the right idea? Btw I’ll be jetting up

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9/25/2018 6:48 AM

I would be more concerned about jetting...put the 13 on and call it good.

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vomiting equals disqualification.

9/25/2018 1:06 PM

I feel like the 13/49 will let the bike fall on it's face in deep soft sand. Back in the day, I ran 13/53 on my 125's in deep soft sand.

Paw Paw

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9/25/2018 3:24 PM
Edited Date/Time: 9/25/2018 3:31 PM

Maybe some specifics on the sand track? Can't imagine a 12 tooth front anywhere.. 13/53 would kill the top end wouldn't it?

Edit- I see what you are saying... 5 spd, even MXA says something about a 53!

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vomiting equals disqualification.

9/25/2018 3:59 PM

BR8ES wrote:

Maybe some specifics on the sand track? Can't imagine a 12 tooth front anywhere.. 13/53 would kill the top end wouldn't it?

...more

It’s a fast long track medium deep and the corners are outside lines. We run sandtyres and it gets watered. 5th on the 12/48 (4.00) feels like 4th on my low geared 450.

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9/25/2018 4:00 PM

Paw Paw 271 wrote:

I feel like the 13/49 will let the bike fall on it's face in deep soft sand. Back in the day, I ran 13/53 on my 125's in deep ...more

6spds were they?

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9/25/2018 5:09 PM

I would also go a couple clicks up on the compression and add a psi or so in the front compared to the rear, helps keep the front up...if you've a 5 speed and your only other cog is a 49, then just add that if you don't have others to chose from. Backs up what MXA and Paw Paw mention. Jet that baby fat as you will be on the main the whole time.

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vomiting equals disqualification.

9/26/2018 11:02 AM

My cr 125 on deep sand I rode 13-53. And kept it WFO All the time, seriously.. just add clutch! air striker carb jetted spot on but I raised the needle.

forks flush with the clamp and some more preload..

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