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2/11/2018
Location
Puyallup, WA
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wertman194
2/28/2018 11:09pm
2/28/2018 11:09pm
Edited Date/Time
3/4/2018 9:55pm
So as I am disassembling this bike and noticed a lot of play in the swingarm. Further investigation revealed the swingarm pivots in the frame are all wallowed out. I can actually move the bolt almost 3/16" in the frame hole! Has anyone ran into this before? I was thinking of welding it up and recutting the hole but not sure if it would be centered correctly. I am thinking the best fix would be to enlarge the hole until it is round and fab up a bushing and source a new pivot bolt.
You can perhaps use measurements from 'mirrored points' from one to another to achieve accuracy in the mount hole placement. And use the advice I give further on.
Or, If both sides have a 'healthy' section of the original bolt hole left, you can use a Engineers Washer ( goodness only knows if that term applies in the USA) or a machined washer / spacer to use as a drilling guide.
If you can find enough of a segment of the original bolt hole arc, you can 'match' the washer / spacer to that arc (and perhaps the 'mirrored point' measurements I mention above) and tack weld said Washer / Spacer to the Swingarm mount plate. This given my assumption that an 80 model has just plates as the swingarm mount area, and not a three dimensional section as later bikes did / do.
The tack welded part then gives you a guide for accurate drilling, even with a hand held drill. Just go in small steps as you go towards the ID you are working to. If it's a hardened Engineers Washer, you'll need good drill bits, and a bit of cutting fluid / lube as you go through to the size you want to achieve. The drilling for either, making a much larger, 'completely circular' hole for then welding in a 'top hat' type spacer that you then weld in, or if you just infill with weld the flogged out plate on the inside of the frame. But, infilling the weld will require you to then make sure the resulting face is filed / machined flat to mate with whatever swingarm spacers / end plates the bike used. It's Very important for the inner face to be perfect! A 'top hat' type spacer welded in obviates the need for what can be a Very tedious chore. And, will be much stronger. Of course, you will probably have to source a longer SA pivot bolt. I very much recommend that you go the machined 'top hat ' spacer route.
Of course, a full weld around the circumference of the Washer / Spacer / 'top hat' insert is to be done. A 'top hat' insert can also have the inner , swingarm side circumference welded.
I write from having a TIG (for decades, so I guess I'm a bit blaze' about it) , and I urge you to Not f**k around with any other form of welding. Cripes, every man and his dog can get a few hundred dollar TIG, from their local Hardware store now, so it's not hard to get access to one. Whether or not the bloke / blokette that has it, knows how to weld well with it? There's so many people with "all the gear, and No idea" now. It's not hard to find someone who has a TIG, and Knows how to use it.
The Shop
I think I went up to 17mm dia I made the heads quite thin, only 1mm. So the stock spindle length was fine. (we make new spindles by the way).
If you fit the swingarm bearing pivot bushes, end caps and engine hanger bracket (you could bolt the engine cases in aswell) along with the spindle and new bushes it will hold everything in line. You can then tack the top hats in place.
Tig weld, or braze. DO NOT GAS WELD THEM!! Gas welding will make the weld and surrounding area brittle and much mire prone to cracking.
Stevie
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