TOPIC:

When I replaced my swing arm bushings in my KZ650 the sleeve was a tight fit. That was 8 years ago (12,000+ miles) and it's never been a problem. Having greased the swing arm every 1,000 miles everything works as it should. I suspect it simply breaks in with a little mileage. Personally I'd prefer a little tight over loose. Ed

I greased my swing arm. It was tight but now it's loose. Another project. The old grease got hard and the arm was tight. This time I'll go with needle bearings when I get my new HP shocks. Yes, better tight.
Steve

OK I think I have cracked the code on this issue, and as usual, once I did it seemed obvious, and like I should have sussed it out sooner. It's like when you look for something you misplaced, it's always in the last place you look, right. Funny how that works

ANYWAY


I inserted the pin and watched with a beady eye where it was contacting the collar on the far side. Then the lightbulb went off in my head and I rotated the pivot pin, rechecked. and this became clear, especially when I rolled it on my flat-enough block with a flashlight behind it:



I'm going to see about finding a better pivot pin, that's straight and with less pitting as this one is showing. Anyone have one laying around gathering dust?

Thanks a bunch for your thoughts, much appreciated.

N.

Found one on eBay, new, $40 shipped, Done.

I don't believe the pitting on the swing arm bolt is having any effect whatsoever on the movement of the swing arm. There should be a swing arm sleeve (see parts #5 in image below) near each end of that bolt. Each sleeve should have a curved grease slot on its outer circumference. When you apply grease to the grease fitting on the swing arm the grease squeezes between the outside of the collar (see part #7 in image below) and the swing arm and goes into those slots and lubricates the sleeve/bushing surfaces. Those sleeves, not the bolt, are what bear against the swing arm bushings (see parts #6 in image below). The swing arm should have a bushing in each end, and those bushings rotate on the sleeves. The sleeves do not rotate on the bolt, so the roughness on the bolt should not affect the movement of the swing arm. Ed

If the "sleeves/bushings are dry, they will freeze. The bolt takes on the job as pivot. Kawasaki had a bad habit of installing the grease zerk in a position, it was hard to get to it. Guess how I know that? Being the bolt doesn't have lubrication, it will gall and wear away. It can also suffer rusting because of no grease to protect it. I've changed my Bushings 4 times in since I bought it in 75. This time will be with needle bearings and races. The bolt will go too.
Steve

Ed, thank you very much, that was very helpful.

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 on 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 either 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 as you guys are suggesting. Much clearer in my mind now.

Related question: the dust caps with the o- rings: those are slightly dished so they themselves don't bind, yes?

P.S. Agreed, the pitting isn't so much the problem, but the bend is certainly causing friction (and binding) between the collar and the bushing.

P.P.S. The pitting is relevant because material is missing, and introducing play between the bolt and the collar. Should not matter much if everything was perfectly clamped and motionless relative to the frame, but with room to move, I think it does.,

When the bolt is tightened the end caps, sleeves, and collar are all squeezed tight together between the frame. The total length of the bushings and swing arm is a little shorter than that of the sleeves and collar so it doesn't bind between the end caps. The o-rings help retain the grease, and I believe the end caps are slightly dished to keep the o-rings in place. Ed

Hello lads!

Pardon the delay, I had a big trip in between, my wife's "Bucket List" trip, and we were gone for a month touring western USA national parks in a rented RV. All was not lost though, we threw her F650GS on a hitch carrier on the back of the beast, and used the bike to tool around Bryce, Zion, and Yellowstone areas, and I got to sneak off and do a couple of days solo in Colorado too. So that kept the motorcycle Jones at bay at least.

I am back in the shop now, scratching my head and wondering where I left off in a few respects, and today was Assemble the Carburetors Day.

When disassembling the bike I discovered that I had 26mm carbs, likely off a later KZ900, and so wanting to return it to something close to correct condition, I sniped what looked to be a promising set of 28mm Mikunis on eBay that were advertised to be free, slides moved freely and smoothly, just needed cleaning, etc.

What arrived turned out to be somewhat different than that. The slides were stuck tight, and the float bowls and top caps had been carelessly brightened with a wire wheel, scarring both. I struck a deal with the seller on a 50% refund, and tore them apart.

[img]http://http://noblehops.smugmug.com/Motorcycles/The-Friendship-Bike-1975-Z1-90/i-BXsM6pv/1/L/IMG_8899-L.jpg[/img]



I sent out 95% of the steel for zinc plating, glass beaded the bowls and covers to remove the worst of teh scars, vapor blasted all the aluminum, and now I am putting them back together.

Will hopefully have a dandy "after" photo for you shortly.

OK, here's your "after shot, but i'm not quite done.



Apologies for the blurry pic, but I need this wee little metal spring. I can't find it in a quick Googling, but I think it might be called a "leaf spring".



I need one, would prefer to get two. Any leads? Or failing that, does anyone have a spare they'd part with?

TIA,

N.

Stand down on that, For reference, Kawasaki calls it a "lock washer" part #16054-005

Found it on eBay.

Grrrrr.