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

TTR-Tony · Newbie

Proper chain adjustment?

LRJ · Senior Member

My Yamaha owner's manual (2000 TT-R North American) indicates that the chain slack should be measured (and adjusted) while the bike is on the ground, but unladen. The "wheels in the air" part is just to find where the chain is tightest. Then you are supposed to set the bike down to measure the slack. I am surprised that you don't end up with the chain being overly tight, using the technique that you describe. Perhaps I am misunderstanding the description of your approach.

TTRfan · Super Guru

The extract below is from the Yamaha owners manual and suggests checking with the bike on the ground:

Chain adjustment - copied from owners manual.jpg

burton500 · Veteran Member

I downloaded the 1999 manual, and that says "35 - 50 mm with elevated rear wheel".

Lee

barra8 · Guru

burton500 wrote:
I downloaded the 1999 manual, and that says "35 - 50 mm with elevated rear wheel".
Lee

That's what my 1999 manual says also...

Remember to turn the wheel around to find the tightest position & tighten it there.. .....

...............

Jarrah.

Pendo · Veteran Member

On my Blue TTR, I find when I adjust the chain the lower chain guide restricts the movement. The chain will only move so far before it is restricted, which can give a 'false' measurement. So I usually go one setting too far and then back it off. Does anyone else notice this?

alanwebbo · Veteran Member

As the engine sprocket and swinging arm spindle are on different centres, the chain goes tighter as the suspension compresses. I used a ratchet strap around the swing arm to hold it in its tightest position then set the wheel position so there was a little slack in the chain. This ensures that the chain doesnt prevent full suspension movement or overload the wheel bearings or sprocket shaft bearing when the suspension compresses. When the strap was removed i took a measurement from the swinging arm to the middle of chain run with the rear wheel off the floor. next time i adjust the chain i can use that measurement without having to compress the suspension again.

-- Edited by alanwebbo on Saturday 21st of February 2015 06:45:26 PM

dogwheel · Member

Hi Alan, I'd like to know that measurement from the swinging arm to the centre of the chain run please.
Cheers,
Robin.

alanwebbo · Veteran Member

the distance will depend on the sprocket sizes you are running and the length of your chain. You just need to go through the procedure once on your bike to get the measurement.

dogwheel · Member

I'll be doing that. Thanks for the idea, which avoids the slightly confusing other approaches, what really matters is keeping enough slack to avoid damage to the gearbox output shaft/bearing/seal.

Robin.