Does the 426 have a weak rear hub???

Hey all. I have had a '00 426 for about 9 months now and have had a plethora of problems. The latest is that I ripped my sprocket right off my hub and took part of the hub with it. The chain then proceeded to rocket through all the stuff on the rear end eating anything in its path. I spent about $1000 getting all that back together just to find out that when the chain finally bound up it broke one of my gears in my transmission. I have had some local people tell me that they have weak rear hubs and the dealership where I got it said they have had a few complaints. However when I called Yamaha directly they of course had never heard of any problems. I was just wondering if anybody else has had this problem.

:) Joe

Do a search under this subject. I think alot of people concluded that the exploding hubs were caused by people overtightening their chain. I have had no trouble with my hub. I made a plastic go no-go gauge shaped like a rectangle with a corner cut out, like a fat "L" When placed over the last bolt on the rubplate, the chain must fit over 1.6 inch cutout portion, but not over the 2.0 inch outer rectangle.

I tried it on my friends bike, who is a long-time MXer. His chain was way too tight, much less than 1.6 inches.

I suspect that the people that think the hub problem is due to a too tight chain are right.

I know someone that has had two "explode" on him. I just watch my chain ring bolts and run the chain at "four fingers" loose rather than the "three finger" loose that I ran on my 99 YZ250.

Only once did I run the chain slack at 1.6" -at the end of the ride I found all the sprocket bolts loose! Now I don't go below 2" of slack and allow up to 2 1/4" before adjusting - not a real problem with a good chain. The manual is wrong on this.


I had the same encounter as you.

Hubs either come apart from poor castings, or chains that are too tight. Poor castings are very rare.

Poor castings fail almost immediately, and can be verified by shiny surfaces within the breaks, (the bad casting pocket rubs internally, polishing itself, before the break occurs). Take a close look.

The chain spec of 1.6 is the most common problem. If you take a close look at your failure, you'll find that the sprocket was not ripped, but pulled outwards to the left before the actual hub failed.

A chain setting at 1.6 with the chain snug, is too tight. A semi snug chain at 1.7 is about the tightest you can go. Make sure you measure the chain at it's tightest point since they don't stretch evenly.

And loctite the sprocket nuts or get the nylon self locking ones.


<font color="navy">The same exact thing happened to me. I had just purchased new chain/sprockets and after the first ride they were shot! My sprocket ripped loose taking the hub and chain guide with it. It only costed me about $300 to fix it but I did all the labor, and my trans was fine. My chain was adjusted correctly, everything was fine.

Originally, I thought a rock may have jammed between the chain and rear sprocket but I've heard of a few people (including you) talk about the '00 426 having weak hubs. I'm beginning to think there must be a problem.



[This message has been edited by teamtoxic (edited 08-03-2001).]

i broke 2 chains running 3 fingers so now i am going to 3and a half but the hub thing i think is bad casting on eary oo models not 1 o1 has a broken hub

I haven't had any problems whatsoever on my 'o1, but my buddy grenaded the hub on his '00 last year. Very $$$$$$

[This message has been edited by Roostie_1 (edited 08-03-2001).]

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