Kz750 E1(4) swingarm swap with ZRX1100

Hello guys,

Doing a build with a kz750 1981 bike and have just bought a ZRX1100 swingarm arm to put in. Just wondered if anyone has done this before? as I will need to do some fabrication for it to fit.

Cheers jim

You really should try the search button. I did a really quick search and came up with several threads like this.

www.kzrider.com/forum/5-chassis/606836-z...rm-pivot-idea#770026

I did do a search thanks, and have seen the attached thread before, but thank you for your time, although a little sarcastic.

My main issue is how to fit the swing arm into the frame as it’s width is larger. It’s only a few mm, so was looking at the different options and what bushing/seals are actually required. The pivot pin/spindle and sleeve from the kz750 could be used with replacement bearings with the required 22mm ID

Cheers jim

I am currently doing a frame off resto-mod on an '81 KZ-750E myself. Going with a vintage Superbike theme. I decided to fabricate a tubular brace and weld it to the bottom of the stock swing arm. I made a weld fixture, and have the tubing bent, but haven't gotten any further with it yet.

After welding and metallic silver powdercoat.

Skidmark: any pic of the welding fixture?

I used 1/4" steel plate, with 3" x 3" x 3/8" wall angle. I used the OEM pivot bolt and axle, which is why the washer stack is on the one side.

You need to center whatever rear wheel you are using to the arms shock mounts then drop a straight edge off either side of the bare rim to find the center of the pivot tube so you can work out how much needs to come off each end of the pivot to keep the wheel on the centreline.
The 750 frames s/a mounts are equidistant to the frame centerline so that makes it simpler.
I use a home made tool using some tool steel and an old spindle powered by a hand drill that fly cuts the ends which is guided by the pivot tube to keep everything truly square.
Just make sure you account for the thickness of the end caps and any shims.

Simplest way to solve the spindle sizes is to sleeve the pivot tube but there's plenty of other ways to do it.

zed1015 wrote: You need to center whatever rear wheel you are using to the arms shock mounts then drop a straight edge off either side of the bare rim to find the center of the pivot tube so you can work out how much needs to come off each end of the pivot to keep the wheel on the centreline.
The 750 frames s/a mounts are equidistant to the frame centerline so that makes it simpler.
I use a home made tool using some tool steel and an old spindle powered by a hand drill that fly cuts the ends which is guided by the pivot tube to keep everything truly square.
Just make sure you account for the thickness of the end caps and any shims.
Simplest way to solve the spindle sizes is to sleeve the pivot tube but there's plenty of other ways to do it.

wow that tool is brilliant. You hold the cutter with a set screw?

Yes. Just a piece of 1/4" tool steel held with a set screw.

whats up man. Do you have any more information on the swingarm? Im using the same one you are for my build. 78 kz650 with 08 r1 front end and zrx swingarm.

I didn't pay mush attention to this thread as I don't see myself ever doing something like this, but none-the-less Zed105 what an ingenious idea for trimming the swingarm. I will have to put that one into my memory banks for future reference if needed. I can't quite tell from the picture you posted, but is the tool steel post just placed in a round hole and locked down with a set screw or did you manufacture the hole in the spindle to fit the tool steel post?

Rick H.