swing arm shims?

[elrichjoshua]

Hey, I'm putting together an old barn find xs650 that I picked up a few years ago. One of the ugliest you'll ever see. I have just finished painting the frame and swing arm and have new bronze bushings in the swing arm. New seals too. I don't recall any shims when I took this apart a long time ago but when I fit the swing arm in place, it has about 30 or 40 thou play without tightening the bolt and nut. I don't really want to bend the frame. Seems like it should be a snug fit. Mikes xs doesn't list any shims on their site. I can put a dial indicator on the arm and make two shims half the size of my measurement. Anyone got and extra old shims or have a recommendation?

 

[XSLeo]

Compressing the frame when tightening the pivot bolt is a normal part of it. Once you get the bolt tight it holds the pivot tube under compression so that the swing arm pivots around the tube. Once you get it tight and you have excess side to side movement then worry about shims.
If you find it needs shims they may be hard to find. To make them you need the center hole bigger than the pivot tube and just large enough outside diameter tio fit snuggly into the seal. That's the way Yamaha made the shims.
Leo

 

[elrichjoshua]

I can tell the the pivot tube is a few thou longer that the swingarm, so that when the frame tightens up it pinches and locks the pivot tube. I had an xs1b way back when and I put the bronze bushings in and seem to recall that it was a nice slip fit between the frame. I can see the shims as you describe them and that can only work to tighten up clearance that is a result of the pivot tube being longer. I don't think that clearance is a concern, just a couple of thou. I recall the torque being something like 37 ft/lb . I don't want to over do it if that's what it takes to squeeze the frame. I'd rather make shims that do contact the pivot bushing to take up the space between the frame, so I get a snug fit without distorting the frame. Then I can see if the shims you describe are necessary. I have this crappy Clymers manual that has no torque specs. You wouldn't happen to know when the spec i s for the swing arm bolt, would you?

 

[elrichjoshua]

I can tell the the pivot tube is a few thou longer that the swingarm, so that when the frame tightens up it pinches and locks the pivot tube. I had an xs1b way back when and I put the bronze bushings in and seem to recall that it was a nice slip fit between the frame. I can see the shims as you describe them and that can only work to tighten up clearance that is a result of the pivot tube being longer. I don't think that clearance is a concern, just a couple of thou. I recall the torque being something like 37 ft/lb . I don't want to over do it if that's what it takes to squeeze the frame. I'd rather make shims that do contact the pivot bushing to take up the space between the frame, so I get a snug fit without distorting the frame. Then I can see if the shims you describe are necessary. I have this crappy Clymers manual that has no torque specs. You wouldn't happen to know when the spec i s for the swing arm bolt, would you?

I can tell the the pivot tube is a few thou longer that the swingarm, so that when the frame tightens up it pinches and locks the pivot tube. I had an xs1b way back when and I put the bronze bushings in and seem to recall that it was a nice slip fit between the frame. I can see the shims as you describe them and that can only work to tighten up clearance that is a result of the pivot tube being longer. I don't think that clearance is a concern, just a couple of thou. I recall the torque being something like 37 ft/lb . I don't want to over do it if that's what it takes to squeeze the frame. I'd rather make shims that do contact the pivot bushing to take up the space between the frame, so I get a snug fit without distorting the frame. Then I can see if the shims you describe are necessary. I have this crappy Clymers manual that has no torque specs. You wouldn't happen to know when the spec i s for the swing arm bolt, would you?

Whoops. I'm just saying that it seems wrong to me to have to squeeze the frame as much is it seems in this case. I replaced the pivot tube and bolts. The old bushings were frozen to the tube and the tube was pivoting on the bolt. Seems like it wasn't pinched properly to lock it in place. I'll come up with something but I want to check it at the proper torque setting. Thanks for your input.

 

[elrichjoshua]

Just found the setting. 47 ft lbs.. I don't like the idea of squeezing the frame any more than a couple of thou. Seems like the more pressure/torque required to squeeze it, the less you are actually squeezing the pivot bushing. I may be a bit anal here but that 's the way it is.

 

[XSLeo]

I have several factory books, in the A,B,C,D book reads 36-58 Ft/lbs. I would torque it to the lower number and check it out. With just the swing arm in place, lift the swing arm up to horizontal. Let go, does it stay in place? If not up the torque 5 Ft/lbs. Try again. At some point, if your bushing to pivot tube clearance is ok it will hold position. As I recall on the last one I did it took around 50-55 Ft/lbs. of torque.
Once you get it to stay in place it should move freely by hand. It shouldn't take a lot of force, it should move with just a bit.
This test is something anyone who thinks their bushings are worn should do.. If the pivot bolt is loose it lets the pivot move and pivot on the bolt. The bolt to pivot tube has a fair amount of space to allow ease of removal.
I bought an 81 five years or so back that appeared to have excessive swing arm play. Upon closer inspection I found the threaded part of the pivot bolt broken off and a PO drilled and tapped the pivot bolt for a 5/16's bolt. This couldn't tighten enough to compress the frame to hold the pivot tube. Feeling like excess play. I had a spare bolt out of a parts bike, swapped it in, and tested as I described. With enough torque it acted fine with the stock Fiber bushings. They are still fine today. I keep them greased. A few pumps every oil change does it.
Leo

 

[David Toll]

Elrich I had this problem a couple of months ago. Yamaha still carry the shims in stock, (at least in Oz), so your dealer will be able to help. Failing that, Heiden tuning carry the things, I bought six for 23.50 euro (thanks Michaelo). Took a while to arrive from Holland because they sent them standard post but they did the trick.

 

[gggGary]

Go get 3/4 machine shim or two at the local hardware add them between the frame and duct seal. so you don't have to crush the frame in so far. This is a separate deal from the factory shims to set the bushing clearance inside the dust caps. there's a way back thread about this. I am with you, trying to suck the frame in that much is stupid, and creates alignment and stress problems, probably why there have been reports of broken threads on the pivot bolts.