6.06. Swing Arm

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6.06.01 Rebuild and Links

Ken's procedure on rebuilding the swing arm can be found here at the 650rider.com site.

Doonie's procedure on fixing the swing arm bushing can be found here on Sarge's website.


6.06.02 Swing arm bearing fix

The cost is about $50 Aus, November 2003.

You will need 200 mm of "Thompson" linear bar, which should be available from a good bearing supplier. The one you want is 25 mm hardened and ground shaft. (0.5 mm nitrided and ground steel bar) You will also need two m16 x 100 mm socket head cap screws and some teflon coated bushes; two plain and two flanged.


The numbers are as follows.

Brand names: Glacier or Glycodur Plain bush: MB 2520 DU 25 x 28 x 20 Flanged bush: FMB 2521.5 DU 25 x 28 x 21.5 The flanged bush has an o/a length of 21.5mm The flange thickness is 1.5mm, o.d. of flange is 35mm.

Remove the existing bushes and clean out the inside of the swing arm tube where the old bushes were. The hole may not be round or accurate. We machined a plug to exactly 28 mm and then ground (with a die grinder) and scraped the swing arm hole to accept a test plug as a tight push in fit.


Image:swingarm.jpg


Machine a test plug at 28 mm +0  : -.001 mm

Drill and tap the bottom of the swing arm to accept a grease nipple (zerk) and make sure it doesn't extend into the swing arm. You can do this by packing it out with small washers. Insert the grease nipple with a suitable sealant.

Machine the hardened and ground tube as shown and also grind two small flats in a position opposite the grease nipple. This is to allow a bolt to be screwed in and onto the shaft to stop it from turning in the event that it ever needs to be dismantled. The length of the tube is determined by measuring the width of the swing arm, plus 3 mm (two flange widths) plus .02 to .03 mm for end play.

I didn't reuse the rubber seals (originally supplied) as I reasoned that positive pressure applied by the grease coupled with the extremely small amount of difference in size between the shaft and the bushes would keep any foreign material out. Grovesy wasn't sure, so we machined the flanges down to accept the seals, and added the thickness of the seals into the length equation.

Machine the bolts so that the area where the shank meets the bottom of the head is undercut to allow for a hard up square fitting of the bolt head to the frame.

Grind off the raised tab on the left hand side of the frame where the bolt head will go.

Insert the bushes. Insert the shaft. If necessary, scrape the teflon bush to remove tight spots. These may occur if the swing arm is out of round.

Grease the shaft.

Affix the swing arm to the bike, applying anti-seize to the threads on the bolts and two the shaft of the bolt where it sits in the frame.

Doonie.

6.06.02 Swing arm rebuild

Rebuilding the XS650 swing-arm

Submitted By: Kibokojoe


XS650 Rebuilding the swing-arm First I have to thank the members 650 bulletin board for submitting most of the following information. The verbiage I use for the parts are not what we normally use but these are names used in the manual and on www.mikesxs.com web page where I ordered my parts.

Disassembly 1. Place bike on center stand 2. Remove rear tire 3. Remove shocks 4. Remove chain guard 5. Take link out of drive chain (don't pull the chain out) 6. Remove grease zerks (8) from the pivot shaft (5). 7. You might want to screw a flat head bolt into the zerk hole on the side of the pivot shaft you will be driving from. This will keep the zerk hole from getting distorted when you are hammering on it. Trying to reinstall a grease zerk into a distorted hole is no fun. 8. Flatten the lock washer (6). 9. Loosen nut (9)on pivot shaft one half to one full turn, no more. Tap nut with hammer or hard plastic hammer. You might want to use a piece of wood between the nut and your hammer. Don't want to distort the threads on the pivot shaft or nut if you are going to use them again If the pivot shaft moves great "You're a blessed individual". If your pivot shaft was like mine it will not.

After you have finished cussing you will need to shoot some PB Blaster (PPB) into the grease zerk holes followed with some compressed air. Keep doing this until you see the PBB comes out of the swing arm. You will need to do this to both sides. I let the PPB sit for several hours and then using a drift pin (flat tip) I drove the pivot shaft out of the swing-arm. PBB is some amazing stuff. I have seen nuts and bolt rusted to the point where I thought they were welded, but after soaking in PPB they came right off. I don't know what is in that can but it has saved me at least a pound of flesh on my knuckles. (No I don't work for PPB but I am definitely a fan now)

10. Next you need to remove the swing arm bolt tube. I had no problems removing this with a larger drift pin. It slid right out.

11. The plastic swing arm bushings on the other hand were a little trouble. To remove the swing arm bushings assemble a hacksaw through the swing-arm and cut through the bushings. All you need to cut is one side this loosen them enough than can be punched out with a drift pin. If you are careful you won't cut into the swing-arm and just cut through the bushing. An alternative to this method is to simply heat the bushes one at a time with a propane torch. The bushes will shrink and 'crisp' and can then be easily removed without risking damage to the inside bearing surface of the swing arm.

Assembly To press the new bushings into the swing-arm get some stout all-thread (I think mine was ¾" but I am not sure), nuts and large washers. Start the bushings into the swing-arm with a rubber mallet, lightly tap them into the swing-arm just enough to get them started. Do not try to pound them in you will distort them. Assemble the all-tread, washers and nuts. Then simply tighten the nuts until the bushings are properly seated.

That's it if you have any questions or suggestions drop an email at cfsboy@sbcglobal.net


Kibokojoe.


Image:swingarm1.jpg


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