it's a time to change a drive.

Are sprocket 15t or 45t a same us xr400r?

http://www.pbr.it/images/stories/com_fo ... 904/10.gif
http://www.pbr.it/images/stories/com_fo ... 8904/9.gif

Will i fit this to my crm 250 mk3?

How many links of chain i need to this sprocket sizing?

Most people run a 13/ 45 combination.
I do a lot of road mileage, so run a 14/45 combination, this also gives better fuel economy, but poorer acceleration.
Mike

Now i have 13/49 and crm have's to much rpm's on 130km/s
I'm curious about fit of xr 400r sprocket becouse i can't find crm 250 mk3 on catalogue? Xr 400 and my sprocket's looks same, but i'm not shure in 100%.

130 km/h

That's about 85 MPH in our language, you should be able to run with a 14 tooth front sprocket easily.
Mike

Yep I run 13/46 and think its fine, don`t do many road miles but seems good for the dirt! and the roads inbetween.

How many links i need for 14/45 sprockets?

I normally order a 114 link chain, if you have to cut it, that's easier than trying to join a chain.
Keep any cut links as a joiner in case the chain ever breaks at some point other than the weak link.
Mike

I count my old drive 14/49 i have 114 links.
I looked at my rear sprocket i have 2 links on 4 teeth.
So i think 112 links will be enough.

What part?
Sorry for my english :(

13/45 +112 links, "0" ring chain.
Mike