crooked swing arm from factory?

this bike does not seem to have been in any major accident yet when i had the shocks off and compared the difference in height of the shock mounting points there was a difference of about an 1/8”.
i also measured from the tire sidewall to the shock rod on each side and got about a 1/16” difference.
could this be a factory imperfection?
any way to figure out if it’s a frame issue vs swing arm?
i originally noticed the difference because i had trouble reinstalling the second shock.

Sounds normal but can't say for sure.

I had a swingarm that was off by about 1/16" to an 1/8". It was in an accident but the damage was to the front end, so I can't say for sure it was from the factory like that or not. I've checked a few others over the years and they were within a mm of or so. It wasn't too hard to straighten. You just need a good flat plate or table top with no warp etc. to use as a gauge.

loudhvx wrote: I had a swingarm that was off by about 1/16" to an 1/8". It was in an accident but the damage was to the front end, so I can't say for sure it was from the factory like that or not. I've checked a few others over the years and they were within a mm of or so. It wasn't too hard to straighten. You just need a good flat plate or table top with no warp etc. to use as a gauge.

so you would, with the wheel off, place the flat plate against the bottom of the swing arm to see if that’s where the discrepancy is?
sounds like it should work if there are no other parts in the way. straightening the swing arm does seem pretty sraight forward once i’m sure that’s the source of error.
thanks!

I was rebuilding the bike after the crash, so the entire swingarm was off the bike...much easier to measure and true up.

a rod through the pivot set in some v-blocks and a rod through the axle slot in set in v-blocks will tell the tale on the swingarm.

leon

Most kz frames I have seen, the frame shock mounts are slightly off. on my kz750 they were 3/16" off side to side. Couldn't hurt to check the swingarm as Leon said.

531blackbanshee wrote: a rod through the pivot set in some v-blocks and a rod through the axle slot in set in v-blocks will tell the tale on the swingarm.

leon

That's what I did.

I think I also used some blocks and a big square to make sure the swingarm axle mounts were equally offset from the ends of the pivot tube. (In other words making sure the axle is centered between the swingarm bosses on the frame, and thus the axle is centered on the frame.)

loudhvx wrote:

531blackbanshee wrote: a rod through the pivot set in some v-blocks and a rod through the axle slot in set in v-blocks will tell the tale on the swingarm.

leon

That's what I did.

I think I also used some blocks and a big square to make sure the swingarm axle mounts were equally offset from the ends of the pivot tube. (In other words making sure the axle is centered between the swingarm bosses on the frame, and thus the axle is centered on the frame.)

if i understand you correctly, that was one of the first things i looked at.
by axle you’re referring to the actual rear axle and not the swing arm pivot bolt?
the axle seems fine as long as the markings are to be trusted. but i’ll be remeasuring everything when i take the wheel off for tire mounting.

In addition to the axle and pivot being in the same plane,
I made sure A = B using a big square. (The green blocks are all the same size as well.)






Then i used the swingarm pivot in the frame as my reference point to confirm the head tube was in alignment . That is easy to check, but difficult to change.

some swing-arms have an offset for chain clearance. what model is this for? my kz1000 LTD was offset 5mm right to left

This was the 550d1 gpz. I didn't change it, I just checked it, according to my notes from 20 years ago. But because I didn't change it, I didnt write down too many details.

I thought the op's bike was a 550A, which uses the same frame/swingarm dimensions as the D1.

Vic got me thinking, so I dug out an old swingarm.

This was a very crude setup. For really checking a swingarm, you would want the blocks to be secure and a flat table.
Also, in these photos I'm measuring from a spot below the axle nut surface. You would want to use blocks there too, to get a more precise measure, rather than from the cast surface on the bottom edge of the axle mounts, which is what I used.


But even with this rough measurement, the offset on each side was the same to within about 1mm.
I'm not sure if you can see in the photos, but the offset on each side is almost exactly 20mm (based on where I'm measuring on the axle mounts).

(Obviously, ignore the non-squareness of the square. It is camera distortion.)