Nessism wrote: KZ650's and 750's were extensively raced and earned a reputation for excellent handling. Guys put these bikes on race tracks with sticky aftermarket rubber and rarely were there issues with flex in the frame causing instability concerns. Removing the factory gussets and replacing them, along with adding little gussets here and there around the frame, begs the question of WHY? The swingarm mod in particular looks to have added a bunch of extra weight which will detract from the handling, not improve it. The steering head looks less braced than before too.

OP would have been better off spending a little money on some new shocks and fork springs. Such mods are useful.

The above is all absolutely true!

Considering the KZ750 was based on the KZ650, and the fact that the KZ650s beat all the 750cc AMA and FIM records (see image below) using unmodified frames and swing arms, the frame / swing arm mods on this bike were a mistake that very likely made handling worse rather than better. The weakest link on the KZ650 / 750 bikes was the rear shocks. Even when new they were barely adequate. Notice in the video below that the stock shocks were replaced with S&W shocks. Replacing the shocks would be the very first thing to be done to improve handling. At the very least I would try to put the frame back as it was before the mods. If the frame was rigid enough for the record setting bikes, it certainly is rigid enough for a street bike. More research should have been done before making frame changes; more research = less hacksaw. Ed

KZ650's and 750's were extensively raced and earned a reputation for excellent handling. Guys put these bikes on race tracks with sticky aftermarket rubber and rarely were there issues with flex in the frame causing instability concerns. Removing the factory gussets and replacing them, along with adding little gussets here and there around the frame, begs the question of WHY? The swingarm mod in particular looks to have added a bunch of extra weight which will detract from the handling, not improve it. The steering head looks less braced than before too.

OP would have been better off spending a little money on some new shocks and fork springs. Such mods are useful.

I knew better than to ask for opinions,if you want to question the handling, Watch the video in the link above. The speed limit is still 55 here and it gets there plenty quick with the sprocket and chain conversion I did. It tops out at about 120. The original frame gussets were removed and replaced, I also added more, reinforced the swingarm and replaced the gussets there too. it is stable as a rock, and even with the shorter pegs, I have no issues putting them on the ground. it's nearly 100 lbs lighter than stock. The wiring is simplified as much as possible and for the most part hidden. The exhaust is straight through with a smaller outlet. If i lost any power it's not noticeable. The steering head bearings were replaced with roller bearings and new races.

Today , swing arm bushings

I'll start over. I have an older post about this 75 i picked a few years ago. As usual it was Americanized and retired to the shed. It took me few years to buy this bike and was finally able to drag it home (great story ). In the previous post after i got it running it is one of the better running Z1's I have owned, so it was shoved in the corner , waiting.
I don;t have heat, and my garage is primitive, so with the unseasonably warm weather the 75 is in the "restore" spot.
The last couple days, I wrenched. First thing I do is swing arm and this one was bad, completely froze up. Today was install new bushings. It took awhile to get the old old ones without heat,torch , I am not repainting the frame or swing arm. I hate spray paint and powdercoat and this original paint on the frame is nice.

Here we go, this is how I got the bike




This is 2014 getting it on the road again after a 20 year hibernation

If you have not changed a drive chain and sprockets before, here are a few things you will need----

An impact wrench. Pneumatic is best, but electric or mechanical can also work.
Without one, you will need a long breaker bar and a willing accomplice to apply the rear brake while you wrestle with the nut that holds the front sprocket on. Yes, it is really tight.

Something to cut the belt with, else remove the swing arm pivot bolt and the left rear shock lower mount.

New high quality chain and sprockets for a chain drive 440. A master link staking tool, unless you get an endless chain in the correct length, in which case you will definitely have to unhook the swing arm and shock.

A can of chain wax or dry Teflon lube.

A grown up torque wrench for installing the new front sprocket.

The most important tool of all is a genuine Kawasaki Factory Service Manual. I think there are some PDF versions floating around, and they come up on FleeceBay now and then.

+ what MartinCSR said.

Just an FYI. From the cross-reference & diagrams at Partzilla for the 1980 Ltd & Ltd Belt, everything is the same. same transmission output shaft n stuff & same Fr chain guide. same Rr hub coupling assy, swing arm, & same chain guard, It should be easy. removing the bolts could be the only hard part.

Rear Brake Shoes. If you don't know the age of the Rr brake shoes, replace them. get oem or vesrah (made in Japan). The adhesive that binds the linings to the shoes can fail from being old & brittle, so a lining can break loose & get jammed between the shoe & drum, locking the rear wheel. It happened to me, so it does happen.

atta boy turn and burn! :evil:




leon

Mock up before all the work forgot to add the mags are kz700 and swingarm is kz650

Wow time flies. So I needed to refernce setting my timing on my ignition for on the 750 twin and decided to log in and continue this thread.

As for my excuse, the 750 twin was running and ran but never fully finished aesthetically and legally...twilight was never mounted. In the meantime I got very into vintage motocross and bought a kx400 and a 80' klx250 along with a few other dirt bikes I now longer own. I've recently decided to get back into finishing this project (it's about time) and want to continue documenting it. I plan to get a go pro soon and document all the procedures o am unable to find instructional videos on. Anyway here's a few things I've done to the bike in the past 3 years.

-dyna s ignition(half 750-4) ignition
-zx6 electrical controls, master cylinder and throttle, cables, and clip ons
-custom milled shims for clip-ons
-shortened frame
-kz650 rear faring
-kz700/kz750 hybrid front end (kz700 bottom end forks,kz750 twin top end forks)
Kz700 dual disc calipers, updated kz700 rear caliper w/ modern rear nissin master cylinder.
-flipped kz750 pegs w/ zx shifter linkage
-shortened and rewelded brake pedal.
-aluminum foot pegs
-powdercoated various parts and frame (so I bought my own Powdercoat and took it somewhere. I realized when I picked up the frame that the powder I bought was actually a textured (stone) powder where as I thought it was a metallic charcoal, so jokes on me. I plan to tear it all down once a its done and sand blast and repaint.)
-kz700 mags
-kz650 rear swingarm(had to grind down the inside of the frame about 1mm on each side






























Everything I've done to this bike is been mostly off top. I kept the kz upper fork legs to keep it low. The kz700 legs are longer but they are pressurized, personally I don't think air shocks are necessary for a street bike, at least for my purpose. I'm not racing this bike however I do plan to do some performance upgrades.
I have a paint scheme that I designed I plan to implement, the main things I'm missing are the lithium batter and battery box I have yet to fabricate. I also have a another surprise as far as cosmetics.

I am currently working on mounting the tail light and glassing the seat pan. Very excited about this bike being finished. I also plan to have a starter hole plug milled unless anyone knows someone who sells them? If you guys have any questions just let me know! Thanks guys