Topic: Trouble installing swingarm bushings

[NobleHops]

Heya gents,

Nevermind that this is a Kawasaki I'm working on for a moment, please!

Said Kawasaki (75 Z1!) has a swingarm that is very similar to an SOHC bike's. I replaced the (metal) bushings though, plus some inner collars, and that's where the trouble began. Swingarm is assembled but not smooth. I pulled the pivot bolt back out and removed it to investigate.

I had a lot of hardware replated (zinc) including the pivot, but I confess I did not prep the pivot very well before I did, thinking the plater would. Nope. There was corrosion and pitting in the area where the pivot collar rides, and there was also a fair amount of damage on the pivot collar (not the bushing) on the chain side. I purchased a set of the oillite bronze bushings, and new pivot collars, powdercoated the swingarm, put it back together.

So I removed the pivot and took it over to the buffer, and polished it in the area of the pivot collars till it was much smoother. Test fit it again, and its now a lot better in either collar, but not good in both. It turns smoothly and freely when it's inserted just so its riding on one or the other of the collars now, but not both. So clearly, the bushings and collars are not perfectly aligned, but it's not detectable by eye.

I haven't had the problem before, these things went back together fine on my other projects, better to be lucky than good sometimes eh?

So who can give me a good education on the best technique for installing these perfectly the first time in the future?

And following the tutorial, who's got a bright idea on how to remediate this one?

TIA for your wisdom as always.

[754]

Sometimes there are just a few high spots to work off.
Easy if you are used to it, but a bit tricky to explain..if we are not in the same room,parts in hand.. If you can blue the pivot, then install you could see any high spots.
 The swingarm off bike..slide in axle and view as it gets near other side..misalignment will be easy to see. If that is the case,  a bit harder to remedy. If you can get an expanding reamer, you can steer it a bit to help cure misalignment.
 First off see if it's maligned between bushings.

[754]

If the pivot shaft can get thru and you twirl it a few times but the should burnish the high spots..if your eyes are good you can see it in the bushing bore.  It can be scraped with a good exactly knife.. Slow process, but it will work if you are patient.

[NobleHops]

If the pivot shaft can get thru and you twirl it a few times but the should burnish the high spots..if your eyes are good you can see it in the bushing bore.  It can be scraped with a good exactly knife.. Slow process, but it will work if you are patient.

It's Frank, right?

Frank, I think you nailed it. I did pretty much as you said, inserted it and watched with a beady eye where it was contacting the collar. Then the lightbulb went off in my head and I rotated the pivot pin and this became clear, especially when I rolled it on my flat-enough block with a flashlight behind it:



Earlier today I tried a variation on your other idea, that worked, somewhat. I inserted the pin, and put an impact on a socket and spun it, using the pin itself to hone the inserts, and that definitely worked, to the extent it was possible with the pin as bent as this.

I'm going to see about finding a better pivot pin, that's straight and with less pitting as this one is showing.

Thanks a bunch for your thoughts, much appreciated.

N.

[754]

Sounding like you just need to polish pitted areas,  clamp shaft in vise or onto table with half hanging out. use Emery or sandpaper. In a shoe shining motion using both hands to polish it.
Then grease it up well and install.

[Stev-o]

Yes, he's Frank and sounds like he's got you ironed out. 

[NobleHops]

Thinking through how this all clamps to the frame, and what's fixed (the bolt to the frame and the bushings to the swingarm) and what rotates (the collar within the bushing) it's clear that collar to bushing fit is the most important interface. The bolt is not rotating, and neither is the collar: it is clamped by the boss on the frame, all the way through the swingarm via the spacer to the collar on the other side, it's not rotating when properly installed. It's fixed along with the bolt. The arm is rotating around the outside of the collar.

So while I still think my bent bolt is contributing to the binding, the takeaway is that's not the most important  fit. The collar to the bushing is.  And thinking this through further, that bronze is relatively soft for a reason: it will break in to the new collars in time. Much clearer in my mind now.