does anybody know where to get the crack that yamaha was smoking when they disided to paint the swingarm on the yz400? also does anybody kwon how to get it off with out damaging the alum. i tried every type of paint remover even some from body shops one was called aircraft paint remover it just won't come off. i've heard of baking soda blasting will this work??

I cant help you with the crack, although that is rather hilarious. You can take the swingarm minus any critical pieces to your local automotive shop where they do engine rebuilds and get it bead blasted or sugar sand blasted for about $20. This will leave a very nice satin finish....not slick !

Keep in mind that you will have to coat it with a sealer made for aluminum to reduce the rate of oxidation and electrolisis.



I just did the swingarm on my 99 wr4. The primer is bonded to the aluminum and that is the coat that is hard to get off. I also tried the aircraft paint remover with little success and started using Klean Strip premium paint remover. You could let this stuff sit for a long time before removing. I used Fine 00 steel wool to remove the paint. Several coats of the stuff and alot work later I had it done. I didn't do the bottom either, just the outside, top and inside up to the swingarm bearings. You can than use very fine 0000 steel wool to give it a great shine and either use a sealer like jaybird suggested or periodic light coats of wax.


99 WR400




Interesting thread.

I have doubts as to the ready availability of crack cocaine to the engineering and design departments at Yamaha. I’m sure that it is opium they are smoking. We all know that the Cannondale designers are smoking some fine Connecticut home-grown (“Put the head on BACKWARDS dude! Whoa!”). But I digress…


I have a very ugly KX 500 in my garage. Is there anything wrong with simply sand blasting the swingarm? Exposure to paint remover makes me feel like a Yamaha design engineer.

sandblasting will leave a pitted finish like in the front part of the swingarm i'm looking into baking soda blasting i heard it will leave a much smoother finish

What about glass bead blasting? The reason I bring this up is when I had the head on a KLX ported, the porter used glass bead blasting as a finishing touch in the intake runners to give a stain smooth finish. I ran my finger along the tunnels and felt the smoothness of that finish after the blasting. Seems like it would be a good method for the swingarm as well. I remember and a pic and small side bar article in a magzine a few months where someone had used some sort of blastin medium to remove the paint on his YZ swingarm and it looked great.

[This message has been edited by Boit (edited 01-04-2001).]

You may not approve of the method but it worked for me:

I did the swingarm on my KX 250 (in my preYZF days) I chucked a soft bristled wire brush into my drill and stripped the paint with that. Then I sanded the swingarm starting with 600 grit wet/dry paper and progressing to 1000 then 1500 grit. Then I polished it with Eagle One Mag Wheel polish. Finally, I hit it with a fine metal polish. It looked like it was chrome plated :):D I went crazy and polished all of the aluminum pieces on my KX (handlebars, shift lever, framegaurds, etc) Slickest '94 in town :D:D:D

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