400EX Chain Length

[Yeller EX]

I have a 2002 400EX and I put a jet kit, k&n filter, a after market baffle in the stock exhaust, 13 tooth front sprocket and that is it. First off I stretched my chain and I am in need of a new one and yes I tightened up the slack out of the chain when I put the smaller sprocket on, so what is the size of a stock length chain? Also I read if I put a new Chain on I need new sprockets is this true?

[CannondaleRider]

I have no clue what stock is. But, simply, count your links. Outer links, multiplied by 2...that's your chain length needed. I'm sure you'll end up just needing a 100 link, then end up chopping a few off.

As for needing new sprockets.....not necessarily. The main thing with that is, if you have a new chain, and new sprockets, they will wear together...and evenly. If you throw a new chain on old sprockets, it will wear your chain a LITTLE faster. Unless your sprockets are really clapped out, I would worry about it.

But, people tend to let sprockets wear out too much... Don't do the whole "Oh, it's still got all the teeth...so I don't need a new one yet" approach, lol.



....Also, this thread will probably be moved to an appropriate forum here soon.

[CSR400EX]

the 99-02 400EX needs a 92 link chain, 03-04's need a 94 link chain. why its different is beyond me lol

[Yeller EX]

I ended up buying a Parts Unlimited o-ring chain that was 120 links and chopped it down to a 94 link chain .

Thanks again for the info!