yz426 sprockets

Well on my 2002 426 i just bought i noticed the front sprocket is going to need to be replaced. Im wanting to know which size(how many teeth) should the new one have to make the bike easier to ride slow as in tight trails. thanks

The smaller you go on the front sprocket or the larger on the rear sprocket will gear the bike down for slower tighter trails. The stock is 14, so try a 13 on the front or add 3-4 on the back sprocket. I defintely would change the chain, and both sprockets at the same time though.

I defintely would change the chain, and both sprockets at the same time though.
That is the safest procedure, and frankly, is more often necessary under typical conditions than not, but it isn't always required.

Check the chain and rear sprocket condition as described in the manual. If you use a chain that is worn beyond the specified length, it will wear your new sprocket(s) rapidly. On the contrary, it is much more difficult for a worn sprocket to accelerate the wear on a chain, although it is possible in the case where a sprocket is very badly worn.

When measuring a chain for wear as shown in the manual, repeat the measurement several times at as many points along the chain as possible. Just a few bad links can cause a lot of problems if you miss it.

thanks, but the bike did not come with a manual. Can anyone tell me how to do this? and if i do need to buy a new chain, what length will i be needing.?

thanks, but the bike did not come with a manual. Can anyone tell me how to do this? and if i do need to buy a new chain, what length will i be needing.?

Check out the manual from motoman...

http://motoman393.thumpertalk.com/tech/files/426_manual.html

Also check out RMATV for cheap front/rear sprockets and chains from primary drive that are really cheap if you do replace them all. :cool:

Try running a 13/50 for tight trails or 13/51 for tight trails with blind corner hill climbs.

Is it a good idea to go down on the front sprocket as opposed to going up in the rear? When I've owned sportbikes in the past I was told by many that going down in the front is harder on the chain, engine, and transmission. That's why everyone chose to go up in the rear for gearing down purposes. On my 426 I'm running 14T front and +3 in the rear and it made a wonderful difference over stock.

Is it a good idea to go down on the front sprocket as opposed to going up in the rear? When I've owned sportbikes in the past I was told by many that going down in the front is harder on the chain, engine, and transmission. That's why everyone chose to go up in the rear for gearing down purposes. On my 426 I'm running 14T front and +3 in the rear and it made a wonderful difference over stock.

It is true that going down on the front is harder on the chain.

Smaller front:

pro: simple, cheap, usually not necessary to change the chain length.

con: Links pivot farther, and so the chain wears slightly faster (there is a bigger difference between a 13 and 14 than between a 14 and 15 in this respect)

Smaller sprockets wear faster because each tooth contacts the chain more often.

Increases the contact with and wear on the slider.

Larger rear:

Pro: more efficient, chain lasts slightly longer.

Con: Cost more

More likely to require a longer chain.

Adds unsprung weight (not much, but it does)

Larger sprockets will drag the chain over the lower guide exccessively

Compromise.

Check out the manual from motoman...

http://motoman393.thumpertalk.com/tech/files/426_manual.html

Also check out RMATV for cheap front/rear sprockets and chains from primary drive that are really cheap if you do replace them all. :cool:

I have not been back in this forum in a while. It is cool to see that people still use Garrett's "Motoman393" manual from his website. Back then TT had about 1,500 members. I sure miss him. It's been over 5 years since he died.

I still have a fondness for this forum, just not much "technical info" to offer. Ride SAFE guy!

Mike Berg

Garrett's Dad

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