03 450 hub cracking.........

has anyone cracked their hub and sproket on the new 450....my dad and I were out at Piru Mx in Socal and he hit the kicker in the back and landed and his back wheel locked up after the hub cracking and sproket bending into the swingarm.....has anyone heard of this and we dont think they will warantee it since he bought the bike in late august...

I think this is the first I have heard of this happening on the new 450. There have been several discussions in the past on this very thing happening to the 426. Some say the hub has casting flaws, others say the sprocket bolts work loose and cause it. Some had it replaced under warrenty, other were left to fend for themselves. I check my sprocket bolts every time I check my chain just to be sure. I would surely try the dealer to see what he will do.


On my 02 426, I'd have a sprocket bolt missing every once in a while, I would just put a new one in. Before I sold it, I was racing it, came out of a turn and dumped the clutch and the bike killed. 5 broken spocket bolts!!! Put in 5 new ones. One week later, the guy who bought it from me had the hub break and sprocket bolts were broke/missing. I bought him a new hub, spokes, and relaced it for him. And it's been fine since. I use red locktite on them, so I know the nuts aren't coming loose. I don't think it was a problem with the hub as much as it was with the sprocket bolts. Once a few of them break, the rest will take more stress and possibly break the hub then. Just my thought. I hope I don't have that problem on the 450. I check the sprocket bolts now before every ride right after I check the spokes.


Research previous posts regarding chain tension. You'll find your answer there.

Good luck!


Beat me too it DaveJ :)

I was going to suggest looking real close at chain and tire alignment in the swing arm......

But as it is now Yamaha should warranty it, it may have been setup incorrectly and thats what you pay for right Setup and Freight :D

Pretty tough toblame it on set-up when it's 2 months old. I always take my sprocket bolts out and blue loctite them when I do my own check of the dealer set-up. I've been doing it for years since I had the bolts coming loose all the time in the past. I go over all the bolts after an hour or two on the bike, they come loose no matter who did the set-up. I had a rear hub grenade after 5hrs on my new 400 a few years back and the dealer said "Sorry, there's nothing we can do" There is NO warranty ona YZ over 85cc in Canada.

try the dealer to see what he will do.

by Cyprice

That is what I was trying to convey. Even at 2 months old the hub should not have puked if it was not defective or incorrectly adjusted.

If then the user failed to check his own ride out then its his fault but I did not assume that, I figured they new what they were doing based on the posts

Setup and prep won't have much to do with rear wheel alignment. The YZF's (and all other Japanese/Austrian off-roaders) come in the crate with the rear wheel installed, supposedly aligned and adjusted. Setup / prep usually won't involve a person taking apart what the factory already put together. In no way am I defending assembly at Yamaha, or the dealership, but the manual suggests that the owner check all critical fastners, especially when new. Chain tension, too.

Yamaha "warranty" is 30 calendar days from date of purchase in the U.S. and covers defect in manufacture and workmanship. It will ultimately be your dealer and Yamaha's decision. Best advice, if it's under 30 days from date of purchase, BE REASONABLE WHEN YOU GO IN TO THE DEALER'S SERVICE DEPARTMENT!!!! Be rude or arrogant, and you will not get a new hub/spokes/etc... Be reasonable, and you chances go up.

It looks like your family bought a 450 and a new 250f. If you bought those from the same dealer, they would be stupid not to take care of you. Like he said, stay calm and reasonable, I'd bet they do something to help.


Setup and Prep is supposed to be check over the entire bike, Oil levels and such. In my younger days at a Yamaha shop I worked at that included making sure all the nuts and bolts were torqued and properly installed.

And Yes making sure the wheels were on straight. When I go my 2002 truck I asked for both oil and tranny oil change before I took it off the lot. I also asked for a service to ensure everything was tight. You get charged for it then ask for it. Otherwise they un-box it and sell it to you.

Any new bike I bought I bring home and go over with a fine tooth comb, I know the dealerships don't do the prep work they used to and it sucks..its called profit margin and if you have a kid making 6 bucks an hour doing the chk thats 6 bucks less profit. Poor poor dealer loosing 6 bucks

Lets just say hypotheticly if the dealership did check the rear and found it to be adjusted incorrectly, do you think the hub would have broke?


If it did would Yamaha still be at fault.

I say




Yamaha has been a great company I am loyal to Yamaha. I think if it is camly discussed, Yamaha will take care of it...

My wheel was NOT straight when I picked it up from the dealer. It did not surprise me... This is why I work on my own $hit.

Wheel not stright? How much did they charge you for THAT setup?


Did you adjust the chain? I made a go-no go gauge to easily and accurately check chain tightness (I will try to post a pic). I checked 6 friends with YZFs at my local track. 3 had their chain too tight. Guess why so many sprockets fold over?

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