more torque out of a rm 125

rmrider45 · Sep 22, 2008

in an recent thread someone told me here and also a friend to add a few teeth to the rear sprocket for more torque

i have a 12 front and a 49 rear

what should i change them to to get more power( torque ) for hill climbs. and if i change them wil i see a difference

thx :ride: :ride: :ride:

GarbatyA4 · Sep 22, 2008

I'd honestly try a 50 or 51. You'll loose a bit of top speed.

rmrider45 · Sep 22, 2008

jumping to a 50 or a 51 from a 49 i will get more torque ?

Chili · Sep 22, 2008

rmrider45 said:
jumping to a 50 or a 51 from a 49 i will get more torque ?

Yes. We always went up at least 2 teeth on the rear when my son raced RM125's. We also had Eric Gorr port his 2005 RM125 for low end and saw a great improvement.

GarbatyA4 · Sep 22, 2008

Chili said:
...port his 2005 RM125 for low end and saw a great improvement.

You should try porting a CR250R. It's very fun!

:ride:

rpm12505 · Sep 22, 2008

rmrider45 said:
jumping to a 50 or a 51 from a 49 i will get more torque ?

We ran 12/52 racing mx, rarely needing 6th gear.
If you want to cheap out use an 11 on the front I believe thats about 4 rear tooth change. Good luck

rmrider45 · Sep 22, 2008

rpm12505 said:
We ran 12/52 racing mx, rarely needing 6th gear.
If you want to cheap out use an 11 on the front I believe thats about 4 rear tooth change. Good luck

so just change the front one to a 11?

rmrider45 · Sep 22, 2008

2 strokes for life said:
I would recomend you change your whole drive assembly (rear, front, and chain) because they wear pre-maturely if you just replace one item. I would suggest a 12 and 50-53 because the chain will last longer with a bigger rear and mid sized front.

http://www.rockymountainatv.com/typ...23&navTitle=Drive&webCatId=9&allVehParts=true

Also, if you can make a spacer from your exhaust to cylinder you will get more bottom end power for cheap. Make it about one-eight of an inch thick. Could also try reeds, power blade, and reed spacer. All fairly cheap and give lots of bottom end power to a 125. Hope you have fun.

thx 2 strokes for life this spaCER you told me before about adding 2 or 3 more stock washers before the pipe goes in?

or can i make a spacer out of ?

and could you give me an idea of the name of these reeds or a link

2-Strokes 4-ever · Sep 22, 2008

I wouldn't do an 11 tooth on the front. So few teeth means less chain contact... wearing out the sprocket rapidly.

2-Strokes 4-ever · Sep 22, 2008

rmrider45 said:
thx 2 strokes for life this spaCER you told me before about adding 2 or 3 more stock washers before the pipe goes in?

or can i make a spacer out of ?

and could you give me an idea of the name of these reeds or a link

I think it was me that recomended these mods.
Yes, oem washers.
Reeds: Carbon Tech low end reeds... I think they're still in business?

rpm12505 · Sep 23, 2008

Yes they should all be changed as a set but as far as experimenting $15 vs $60 :whoa: And I dought 1 tooth would result in rapid wear provided you lube your chain once and awhile.

2-Strokes 4-ever · Sep 23, 2008

Fewer teeth on the countershaft means your sprocket "pulls" the chain with less contact (more stress on each tooth.) Example: for anyone who's had/or heard of the old ATKs with the "A-Trak chain torque eliminator" and the limited chain contact it created to the countershaft, having an extra c-sprocket in your fanny pak was mandatory. :whoa:

Chili · Sep 23, 2008

I would also avoid running an 11 tooth front as a permanent solution. If I recall 52 is as big as you'll find for that RM unless you find a custom sprocket somewhere. For a cheap test you can simply drop to an 11 to see if you like the feel. For that matter for a cheap test I likely have some used 51's and maybe even a 52, I'll check the shed today and if I do you can have them for the cost of the postage.

Chili · Sep 23, 2008

Well I spoke too soon, the largest used sprocket I have is a 50, I also have a pair of 49's.

stumanarama · Sep 23, 2008

I'd move in on that almost free 50 from chili. Can't beat the price and it may just be exactly what you're looking for, if not, go out and buy a 51.

rpm12505 · Sep 24, 2008

Chili said:
Well I spoke too soon, the largest used sprocket I have is a 50, I also have a pair of 49's.

I've got you covered Chili. I found a used 52 for him if its not too late.

rmrider45 · Sep 24, 2008

rpm12505 said:
I've got you covered Chili. I found a used 52 for him if its not too late.

thx guys . but i will need a new chain with more links going from a 49 to a 52 ?

2-Strokes 4-ever · Sep 25, 2008

rmrider45 said:
thx guys . but i will need a new chain with more links going from a 49 to a 52 ?

Yup

rpm12505 · Sep 25, 2008

Rmrider45 I can send you this USED sprocket today if you want but don't use it for long if your installing a new chain. It's pretty tired.

CROSS · Sep 25, 2008

just throw a 67 tooth on there... you'll see plenty of torque. :nod:

123ewq · Oct 18, 2008

Exhaust spacer

I found the exhaust spacer after much search :) Enjoy!
type into Google search- mxbonz powrplate
Zach

more torque out of a rm 125

rmrider45

GarbatyA4

rmrider45

Chili

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GarbatyA4

rpm12505

rmrider45

rmrider45

2-Strokes 4-ever

2-Strokes 4-ever

rpm12505

2-Strokes 4-ever

Chili

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Chili

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stumanarama

rpm12505

rmrider45

2-Strokes 4-ever

rpm12505

CROSS

123ewq

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more torque out of a rm 125

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