01 CR125 Sprocket question...

[sportbikenut2]

I am lookin to make my CR a little more woods happy and i am curious as to an ideal sprocket size front and rear for these bikes... I like to jump around alot and hit some killer hills now and then... Thats why i didnt go for a kdx or something like that... This one is light and easy to throw around in any situation..

 

[MikeT]

Do you think it needs to be geared down? If so, then add a tooth to the rear.

 

[Ryone]

You can go a tooth bigger on the front sprocket to gear it down, which is equivalent to 4 teeth on the rear sprocket. These bikes don't like to be bogged, but you'll save a little money by only replacing the front sprocket. One tooth smaller or larger on the front sprocket makes a big difference.

I would also look into adding a flywheel weight if you want to be lugging it in the woods.

Ryan

 

[Jaybird]

Nut,
Your bike comes with a 13t / 51t set-up stock.
That is a 3.9 to 1 ratio.
I've found that a good all around ratio fro a 125 is ~4:1
Changing to a 52 rear, as Mike suggested, and leaving the 13 on the front will net you a 4:1 ratio.

Try to leave the front sprocket as big as possible to obtain the ratio you want.
In other words, when you want more grunt...add to the back sprocket.
If you want more top end, then adding teeth to the front may be the way to go.

 

[sportbikenut2]

It has a stock sprocket on the front now and a 52 tooth on the rear... Still very very fast in second gear when climbing hills... Not sure how much is to much adding to the rear... What all do u all use on the rear of yours compared to stock and how well do u like it.. Also should i go ahead with steel or aluminum sprockets??