more torque out of a rm 125

[rmrider45]

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]

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

 

[rmrider45]

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

 

[Chili]

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]

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

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

:ride:

 

[rpm12505]

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]

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]

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]

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]

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]

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]

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]

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]

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

 

[stumanarama]

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]

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]

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]

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

Yup

 

[rpm12505]

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]

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

 

[123ewq]

Exhaust spacer

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