Sprocket question

[AnthonyB]

I'm trying to make my 81' 250r faster, I already bored it out a little bigger and have 34mm carb on it and was wondering about the number of teeth I could run to make it a little quicker

[NeverLift]

You need to explain what your looking for. Faster top speed or faster acceleration. Its only one or the other.

[AnthonyB]

Sorry ya I forgot to put that, I'm looking for top speed

[John 4]

What size sprockets are on it now?

[AnthonyB]

13 in the front and 44 in the back I believe

[John 4]

My suggestion would be to go up to a 14 on the front and see how you like it. You will notice a difference!

[ScreaminRed]

This may help you....

A tooth on the front sprocket either way makes about 3 times the difference than a tooth on the rear sprocket. 12/40 .300, 12/39 .308, 12/38 .316, 13/41 .317, 12/37 .324, 13/40 .325, 13/39 .333, 12/36 .333, 14/41 .341, 13/38 .342, 14/40 .350, 13/37 .351, 14/39 .359, 13/36 .361, 15/41 .366, 14/38 .368, 15/40 .375, 14/37 .378, 15/39 .385, 14/36 .389, 15/38 .395, 15/37 .405, 15/36 .417

When the ratio goes up you go faster by difference in the ratio. Your torque goes down by difference in the ratio Or approximately 2.5% speed and torque change for each rear sprocket tooth change and 7.5% speed and torque change for each front sprocket tooth change.

Going from 20 inch tires to 22 inch tires will make a difference also increasing your top end speed in each gear and reducing your top torque. Your torque will be decreased by about 10% and your speed will be increased by about 10% Or approximately 5% speed and torque change for an inch difference in tire diameter

[manbearpig]

13/38. just do it. go on... you know you want to. no really. do it. you'll be pumped

[John 4]

13/38. just do it. go on... you know you want to. no really. do it. you'll be pumped
Ill do it, you know I want to!

[AnthonyB]

13/38. just do it. go on... you know you want to. no really. do it. you'll be pumped

I guess I'll try it out:beer
But next question... where can I find one?

[manbearpig]

www.pbisprockets.com

[Dirtweed]

I've got a stock '82 250R that needs a new rear sprocket. If I get the 13/38 what length chain do I need?
Recommendation for good chains?

[manbearpig]

if you run smaller sprockets on the front and rear, without an extended swinger, you can just buy a stock length chain and cut it down

i like RK, but have run DID and the no name $20 ebay chains with no issues to report yet.

[3>4]

Is this the right rear sprocket?
http://shop.pbisprockets.com/product.sc?productId=89&categoryId=16

[ironchop]

I have a 38T first gen 250R sprocket and axle on the back of my 200X

I got my sprocket from here:

http://sprocketspecialists.com/

was about the same price and material as the PBI. They sometimes don`t show it in stock but they will cut whatever size you want. I called about ordering one cut and they had some 38s on the shelf

[manbearpig]

Is this the right rear sprocket?
http://shop.pbisprockets.com/product.sc?productId=89&categoryId=16

Yes. this is the correct 1981/1982 sprocket, although its listes for the 250C model. i have called and spoken with them about his typo, and they have confirmed that it is, in fact, a typo. 250R is correct

[3>4]

That's what I figured. Since the 250r was the only 250 in '81 and '82.