82 RM125 Bottom End Grunt?

[skirider]

Really new to MX bikes and had a chance to ride the RM I bought a couple of weeks ago.

I am thrilled with the bike when it is "in the pipe" as the friggin thing screams (to me at least), what I am dissappointed in is the bottom end grunt...or lack thereof to be specific.

It may just be the bike's design and if so just tell me, but if there is a way to increase the low end performance I would appreciate hearing how. The bike is basically stock except for the DG pipe (head may have some work but I have no idea at this point). On my property I don't have that many areas where I can be in the pipe rpm range and to be honest I like to putt around a bit.....help me if you can.

Appreciate the input!

 

[Chili]

Modern 125's hardly have any bottom end, 22 year old Suzuki 125's have absolutely no bottom end. You could go up a few teeth on the rear sprocket and it would help a little but it's the nature of that beast unfortunately.

 

[skirider]

Chili,

Are rear sprockets with more teeth available for these bikes?

I have not idea what tooth count in on it now other than it is a Renthal brand.

 

[Chili]

Yes rear sprockets are available, If I'm not mistaken RM's have used the same rear sprocket on the 125 from early 80's to current.

 

[skirider]

Any suggestions on tooth count?

 

[Chili]

Dunno what stock was for that year, my 86 was 12/51 my son's 03 is 12/49. I would try going up 2 teeth on the rear from what is currently on there and taking it from there. Cheap sprockets for now until you find the gearing you like.

 

[angst2]

the even cheaper solution is to drop 1 tooth on the front sprocket. Many stock 125 gearings have a 13 tooth front sprocket. Count the teeth on the front and if it is 13 you can replace it with a 12 tooth for about $13. This will do the same thing as increasing several teeth on the back. A rear sprocket would run you about $30 or more.

Eric Z

 

[Chili]

Suzuki 125's have run 12 tooth fronts as far back as I know, I would not recommend dropping to an 11 tooth front.

 

[skirider]

I will check the tooth count on both sprockets and see what I come up with.

Any recommendations for cheap rear sprockets?

Thanks again.

 

[skirider]

Suzuki 125's have run 12 tooth fronts as far back as I know, I would not recommend dropping to an 11 tooth front.

Chili, Why not the 11 front? Just curious!

 

[Chili]

Read the article halfway down the page on this site Titled is Bigger better. CLICK HERE

 

[skirider]

Interesting read Chili, thanks.

I guess I'll be looking at a rear sprocket unless the current front happens to be a 13!

 

[Chili]

According to Renthal's site stock gearing for your bike is the same as my 86 (12/51).

 

[skirider]

As you thought Chili the bike has a 12/51 setup right now. I will have to look around for a rear with a higher tooth count.

Any ideas on inexpensive ones to test with?

 

[gwcrim]

Try Rockymountainatv.com. They have their own brand of Primary Drive sprockets that are reasonably priced.

I grew up riding a '76 CR125 in the woods. I was soooo happy to have a powerful MX bike that the peaky powerband didn't bother me once I got used to it. The suspension sure did suck!

 

[skirider]

Tried rockymountainatv.com and no dice as the largest rear sprocket listed for an RM125 is 51 tooth....

Does anybody know if anyone makes a rear sprocket for this application that is larger than 51tooth?

 

[gwcrim]

www.sprocketspecialists.com or something like that. They make anything your wallet desires.