While duning this weekend, the counterbalance shaft apparrently broke in two, exploding through the middle of both engine cases.

I wasn't even riding it hard, just duning about 20mph in third gear....

Anyone ever had/heard about this issue???

Former happy 1999 400EX rider.... :-(

Any help would be appreciated, as I may be inquiring about this with Honda, since my extend-O-matic warranty just expired six months ago.....

 

damn!that has to suck! i know what its like to lose your balancer. mine put a hole in the case on my old zuki...fixed it with some jb weld and rode it without the balancer. that little 250 shook like hell. i'd hate to ride that 400.

 

I just heard of that happening to someone two weeks ago.I'm pretty sure it was a big bore with 12:1 or more compression.Bum deal. Check out Service Honda for the best deals on factory parts.I got my new frame from them for way less than anywhere else.

 

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Hmmmm..... seems like this is a pretty rare thing....all the more reason why Honda should cover this!!!!

 

they might, but don't count on it. Is your bike modified at all?

 

I think it being a rare thing will keep them from fixing it more than llikely, I'd say more than just you would have to complain about it happening, so they would think it was a defect with some of the bikes.

 

This is not a rare event. This is the third one that I have heard of doing this. My friend AdamSmith had this happen to his bike about a month ago. His was a full race 440 done by Curtis Sparks. The other one was also a 440 done by turtle racing.

I would like to know what the problem is. Is there a flaw in the 400ex crank? I was placing the blame on the increased hp created by modding these motors, but if this happened to a stock bike I wonder if there is a problem at Honda.

 

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The only mod on the bike is a white bros pipe and jetted up a little. Other than that, it's all stock.....

I can understand if major mods are done (cam, 440, stroked, etc), but a Honda shouldn't explode like this.

One item I'd heard is if you put an engine back together, and you are just one tooth off on the counterbalance shaft sprocket, then the added vibration could lead to failure of some sort.

I'm going to scream and shout with Honda as much as I can. So far they recommended I take it back to the dealer for them to do the tear-down and initial cause diagnosis. This was a little piece of info I thought may be useful to all of us. No matter what the circumstances, if you want to try and get a "good-will" comp on parts/labor, then Honda mandates that you have the dealer tear it apart. That's the only way they can trust, or at least have a dependable (in their opinion) way to determine root cause failures.

I'll let you all know next week what the dealer says (Metro Motorsports in Phoenix) when they tear it down. So far the service managers have been receptive to helping out (they will split the labor for the tear down 50/50 and give at least a 10% discount for parts if I have them put it back together). I wonder what kind of warranty period I could anticipate if they put it back together? I would assume 90 days, but hope for at least 6 months...

 

<< My friend AdamSmith had this happen to his bike about a month ago. His was a full race 440 done by Curtis Sparks. The other one was also a 440 done by turtle racing.

>>


then why blame honda? honda didnt build a 440 did they? sounds to me they should be going after the 440 builders not honda.

 

very true, it should be hte 440 builders i think also.