My friend says his friend totally busted his swingarm while jumping his '99 400EX. Has anyone else had this problem?

 

We have broken four so far.

 

My buddy broke his jumping. He is a big guy (230)and likes to jump. He wanted me to weld it up but I told him I couldnt. He talked to his dealer about it and they were great about it and warranted it for him even after it expired. Check with your dealer if its not too far out of warranty you might be able to talk them into it. Sometimes if it is a common thing they will do it.

 

Is there a certain spot on the swingarm where they usually crack/break, or was it a different spot every time?

 

The broken ones I have dealt with come usually come from a combination of 2 things.... Riders 220+lbs and big air. Not really a common occurance for a lighter weight rider still getting big air from what I've seen. I weigh about 175 usually, get plenty of air, and have had no trouble with mine (yet), although I have broken the steel swingarms on my 250R and 350X. I inspect it after every ride though....

I also have an almost new swingarm for sale that was purchased for another project that I changed my mind on. Contact me if you want to talk.

 

All four of the ones we broke broke near the swingarm bolt area. Weight and jumping is not the only things that will break them. How aggressive you ride is a big factor. The ones we broke were on GNCC race bikes with riders that weight around 150 to 170. They had never been on any type of MX track nor had they ever seen a large rider but they had taken a beating from aggressive riding. Basically, the things are designed for your average rider and anything beyond that quickly exceeds the design limits of the cast aluminum swingarm on these bikes. Forget welding, you cannot weld cast aluminum and get it to hold.