A forum for owners of Yamaha TTR250 trail and enduro bikes!

Lee, a good check to see if a chain is goofed is to choose a mid point on the rear sprocket (3 o'clock position) and try to pull the chain from the sprocket.
If you can lift the chain more than half way off the sprocket tooth then it is near replacement. 

When replacing chain and sprockets I would tend to favour a 14 tooth gearbox as minimum size. Any less than 14 tends to wear a chain out by flexing it too much on a small radius, IMO.
It's easy to compensate by adjusting the size of the rear sprocket.
E.G. - my present set up is 13 gearbox 48 rear. 48/13 = 1:3.692 ratio
I am about to change the setup and will go for a 14 gearbox and 52 rear. 52/14 = 1:3.714 ratio
This ratio is about right for the East Devon lanes that can be steep and sometimes tricky.
Your ratio of 13 gearbox and 50 rear = 50/13 = 1:3.846 ratio.
It's OK and acceptable in most cases but for my preference it's a tad too big on the rear wheel and your engine will be revving more for a given speed.

Another point to consider is the chain size. There are two chains used by TTRs.
Mine is a 520 but there is a smaller 428 that was used on the Raid. Ensure you have the correct sprockets and chain set up.
This link gives details:- CLICKY THINGY

Martyn

Hi I'd just like to find out if the chain and sprockets from a 96-06 ttr 250 fit a 1994 ttr 250 Cheers Chris

14/44 was the most common sprockets used in the UK - see http://www.ttr250.com/#Chain_and_sprocket_info

Brian