Broken rear axle!

[MxWFO]

I broke my rear axle yesterday. Craziest thing I have ever seen. Snapped it in two. It's not an old bike either, 2008 YZ450F. Anyway just curious if anyone else has ever broken an axle and if so any idea of what may have caused it. In my case the chain was tightened properly, maybe even a bit loose and ready to be adjusted again. The jump was a pretty good size jump that it broke on, but not so big that it hurt real bad if you come up short. Just curious since I have never seen this happen before, and I've been riding for about 30 yrs.

[jjesneck]

The only reason I can think of other than a manufactured defect, is that your axle nut was not tightened enough.

[MxWFO]

Yeah that's the crazy part. My first thought when I looked down and saw the wheel all cockeyed was that the nut came off and the axle had backed out. But, when I looked at the other side the nut was still on the axle. It actually broke on the flange side about an inche and a half down the shaft. I didn't crash and nothing else besides the oil seal got messed up as far as I can tell. I checked everything over pretty good when I got home. Probably just a manufacture defect. I had just never seen that happen before.

[Moto_Ty]

Dang ? Thats crazy. You got any pics?

[MxWFO]

Not yet. I'll try to get some and post them tonight.

[sixfourone]

Maybe that's why Yamaha increased rear axle size for 09....

[KJ790]

Maybe that's why Yamaha increased rear axle size for 09....

I doubt it since yamaha has been using the same rear axle and hub for 10 years an all of their bikes and I've never heard of one breaking before.

[See-Are-Ef-Too-Thir-T-Ef]

I have heard of kickstart levers breaking on Yams before, bad casting???

[MxWFO]

Sorry about the quality of pictures, but I had to use my cell phone.

[bdrushto]

Damn. Looks like you're the lucky one in ten thousand to get a defective part. ?

[ericinmichigan]

Wonder if it'll be covered under warranty??? Sure seems like it should be!

[MxWFO]

Most of the dealers here are closed on Monday's. Not sure if it will be covered under any warranty or not, but I plan on looking into it tomorrow.

[howard-the-clown]

Most of the dealers here are closed on Monday's. Not sure if it will be covered under any warranty or not, but I plan on looking into it tomorrow.

it should... damn things like that are not supposed to break.

[Rip Wheeler]

Way back in the days, my twin brother had a front axle snap, he was going down a gravel road at about 40 mph. He replaced the axle with a new one from Yamaha and it was a full design change. So about 3 months later, I'm going up a steep hill climb on my dirt bike, not going real fast, wheel pops up at the crest, comes down, front axle snaps!. I bought a new one from Yammie, also a redesign. (both bikes were 70's vintage) But a 2008, I suspect it was from a semi loose axle nut.

[MxWFO]

When it first happened that was my thought, that maybe the nut came off or something. The nut is still on the axle and infact I tried to take it off the axle yesterday and I couldn't get it off. At my house I don't have a vise or a pipe wrench. So it's atleast tight enough that you can't just break it loose with just a wrench. To me it has been a mystery. The only thing I can come up with is a manufacturer's defect. I'm not just throwing the blame on them. If it is something I did I'd like to know. That way it won't happen again. I just can't find anything that I may have done wrong.

[Moto_Ty]

Did you talk to anyone yet about getting it replaced?

[lumpy790]

IMO.....it looks like way over tightening. The nut is bottomed out on the threads so it has been happening (broken) for some time. I would check your hub for over tightening (sideways crushed) damage also.

[MxWFO]

Thanks for the input. Prior to it breaking the wheel spun freely though. Normally from my experience if the axle is too tight the spacers put too much pressure on the bearings and the wheel does not spin freely. I will, just to be safe remove the bearings and check the inside of the hub. I inspected it this weekend and all seemed to be fine. I did not remove the bearings however, since they seemed to work properly and showed no sign of wear. I will inspect further though just to be sure.

[MxWFO]

Went by at lunch and since I didn't have my VIN# on me I have to call them back after I get home. Once I get that they are going to call Yamaha and see if anything can be done about it. Typically there is a 6 month factory warranty, and I bought my bike in Sept. So chances are it won't be covered. That is fine I'm not looking for a hand out it's only gonna set me back $35.00. Well nothing actually since I am using my YZ bucks. Still curious to what caused it though. You can see it broke right where the bearing sits. So you would assume its from hard landings. I broke my ankle a few years ago, so I try to keep the hard landings to a minimum. So that shouldn't be what caused it. My Hondas were abused far worse when it comes to jumping and they are both still fine. Oh well.

[MxWFO]

Well I thought I'd post an update on my situation. Ready to Ride Motorsports really took care of me. I called them up with my problem and they talked to the Yamaha Rep. It looks like Yamaha is going to take care of me also. What at first looked like only a broken axle and messed up oil seal has turned into quite a bit more damage. Turns out the rear brake caliper assembly is bent, the brake rotor is bent. Not a lot more, until you add up the cost to replace it all. Well it turns out Yamaha has cleared it so that Ready to Ride can order me whatever I need to get me going again. I am sending them (Yamaha) all my broken parts so that they can study them and hopefully keep this from happening again. Hope to have it up and going again for this weekend, thanks to Yamaha and RTR.