Broken Swing Arm Extension on a Kawi


Donating Member
So my buddy was getting a rear tire change on his Kawi 1000 when...SNAP! The left swing arm extension just snapped off. I've never seen these snap off like that. Defective part? I think he hit a pot hole or two and it developed a stress fracture. He said he has hit some holes while commuting to work. Hmm? Thoughts?

Don't they say extensions are for track only? I could be making that up but that would be a shining example as to why not to use them on the street. Glad that happened when it did.
Whoa. My buddy is planning on getting those on his R1. Its so hard to tell the quality of those things as you never really know when you order them if they are the cheap China built deals.
I recently changed my mind about extensions...going with full extended swingarm. Too many reports of problems with these things and it's not worth the risk to save a few hundred bucks.
Its better to spend a little more on a full arm exspecially if you are going out as far as those look like
As my friend, who is a machinst and built hundreds of arm back in the day told me:

"I would not trust those around the block. They are selling them for cheaper than what I could buy the material for, that ought to tell you something!"
For you experts out there, I looked these over real close (where the break occurred) and they seem to be cheap cast-aluminum that has been machined. I am fairly familiar with the grades of aluminum, such as 6061-T6, etc., but is there such thing as cast-aluminum versus the higher quality aluminum block, and what is the spec on the highest quality swing arm extension you can buy? Thanks. P.
as I stated before. Most Bolt one swingarm extensions are made incorrectly. As you can see in the pic, there is only about 1/4 material between the pocket ( the area where the axle is adjusted) and the tang ( the area that goes in the the swingarm slotted area). This is where the bolt on extensions fail. It doesnt matter what type pf Billet you use.