Swingarm - repair, replace or just use?

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1/4/2018 1:46 AM

I'm starting my KTM380 project using a 2014 KTM 250SX frame and swingarm and I removed the swingarm bearings and noticed that the swingarm is worn quite a bit on the inside on of the chain side.




I'm thinking it should be flat all the way around like the other side, not have a rounded shoulder on it.

To fit the 380 engine in I need to machine spacers totalling approx 3.5mm. I thought one option could be get enough machined off the swingarm to make it totalling flat, but I would have install new bearings and seals to see if I have enough room to do this. Or I could buy a new swingarm or just use it as is.

Thoughts and suggestions???


1/4/2018 2:06 AM

Id say its fine. You havent lost enough material to weaken it or anything. I would find out why it is being worn down like that and fix it before it does get out of hand.


2009 Kawasaki KX450F
2009 Kawasaki KX250F
2002 Suzuki GSXR 600

1/4/2018 3:28 PM

I don't know why its worn down as I only bought the frame, swingarm and shock from the guy, but given that the swingarm bearings couldn't have been any drier or rustier, I don't think maintenance was high on the previous owners priorities.

Originally was the swingarm directly against the engine case or was there something in between to stop them grinding against each other, such as something in the pivot point in the cases? The parts diagram doesn't show anything

I think I'll get that area as flat as possible with removing as little metal as possible and have the spacer made to match up to it. Then I'll keep a close eye on it.