YZ426F Broken hubs

I believe there was a known problem with the 00's exploding rear hubs, but I'm not sure about the 01's. :mad:

Exploding hub.


We had exactly the same problem.Have a look at the holes in the sprocket where it bolts I think you`ll find they have gone oval.

It does`nt matter how much you tighten or loctite the bolts the sprocket moves when you dump the clutch and simply shears the bolts straight off.I believe this is caused by changing spockets and either not torqueing down correctly,eg.too much, causing the alloy to spread, or failing to use the correct washers and nuts. We found we had replaced the locknuts and the bolts did`nt come thru the nut far enough to lock.You do get some warning that it is about to happen, we kept finding odd bolts missing at the end of races, of course we replaced them with none yamaha parts which made the problem worse since they have different countersink angles under the head.

Since this sorry saga we have replaced the hub and sprocket with Talon and had no problems whatsoever. We also made sure we used talon bolts!
The moral of the story be extremely careful changing sprockets, use manufacturers parts and don`t overtighten.

Dont dump the bike for this, its far too much fun. I think you will find it was your mistake (sorry) especially when you say you could`nt move the remaining bolt.

regards kevin.

Do a search on Thumpertalk.com and you will find threads about blown up hubs. I suffered one on my '00.

I remember seeing a thread someplace (probably Thumpertalk.com) where it was suggested that running the chain too tight could cause damage to the hub. Since then I have been extra careful when setting the chain tension on my YZF.

Yeah, a service bulletin would be a good idea.

Ive heard this before too. It must be the RED loc-tite. Big blue dont like that cherry red goo. :D

I have heard of talon hubs breaking as well.
I know one person who was doing the baja 500 and his excel/talon/white brothers hub grenaded while in first place on his yz-f 250.

the window for proper tension on the chain is pretty small for these bikes. all the grenade-hubs i saw were a result of overtightening.

wp.

Will is right. The manual recommends 1.6 - 2.0 inches of free play. I would stay away from the 1.6. I always keep mine between 1.8 and 2.0 and have never had a problem.

3 finger rule/sprocket bolts/nuts

I have been using the fabled 3-finger rule(at the right end of the top chain slider) on all 5 of my 426's 99-01. I never had a hub explode. Although, I have had the sprocket bolts/nuts loosen up after a race. These should be looked at before & after each ride......I believe if they loosen to a certain point hub havoc will set in as well as destroyed sprockets/chain.:whiner: