I got custom Hagons for my KZ750 LTD a while ago and I definitely thought they were an improvement over the old stock ones that I had, but I did think that the front shocks were decidedly very harsh. I am planning to get cartridge fork emulators for the stock fork I have and then MAYBE - just maybe - I'll do the whole thing and swap out the front end for the 92 GSXR front end that I have with the USD forks. At that point, I'll definitely get a new swing arm at the very least.

The only thing I really dislike about USD forks are the stupid 3 spoked wheels that are an inch or 2 smaller than the original wheels. I don't particularly like the way the KZ750 LTD looks with 2 wheels of the same diameter.

a bushing needs to be machined out and installed,like in the pics i posted of some zxtriples i did for boostable,

hth,

leon

hey guys and gals, i know the taboo of bringing up old posts but i need help. ive got a 1977 kz650-b1 that i recently bought for 600$ runs and rides fine. i have the ability to acquire a COMPLETE 1997 gsxr 750 parts bike from my work so wheels, brakes, swingarm, front end, rear sets and such will all be accounted for. But my problem lies with the stem swap situation. I understand grinding/pressing out the GSXR stem and pressing in the kz650 stem into the GSXR lower tree, but what modifications to the TOP GSXR tree will i need to do to make the GSXR top tree accept the kz650 stem? any information is much appreciated!!!! and yes im going monoshock using the GSXR rear suspension.

I am planning to turn my 1981 KZ550 LTD into a Cafe Racer. I know that there are better models to use as a base for a cafe racer, but this bike is sentimental to me, and time and money aren't a consideration. I'll give a bit of back story on the bike, then lay out my objectives for the build and what plans i have for it currently.

History:
I purchased this bike back in early 2011 when I was 19 years old. It was my first vehicle I had ever owned. I was attending MMI at the time with the ambition of being a motorcycle technician. Traditionally I am a Harley guy, but I didn't have the money for one of those working a job flipping burgers while attending school. I found this bike on Craigslist for $400, and figured it would be a great starter bike to learn to ride on. The bike had been sitting in a storage unit that went unpaid, and the storage place was selling off the unit. The plates on the bike were dated 1998, So i figured it was safe to assume that the bike had not run in at least 13 years. We got the bike home and i tore into it, cleaning and rebuilding the carbs, replacing the battery, Cleaning the rust out of the fuel tank, replacing the tires, rebuilding the brakes, replacing all of the dry rotted rubber components. After a few weeks of work (had a low budget at the time and had to keep saving to buy parts) I had the bike up and running like a champ. I finished school, moved out of Dad's house, and landed a job wrenching for Harley Davidson at a dealership in TN. Not long after I upgraded to a bigger bike, a 1997 Harley Sportster 1200 Custom, and my old Kawasaki sat neglected for years back home at Dad's house in Arizona. Getting my little 550 to Tennessee wasn't a big priority at that point in my life.

In 2013, My twin brother and I took a road trip back out west to visit Dad. I figured it was a good time to bring the Kawasaki back home to Tennessee with me. Neither my brother or I had a truck at the time, so we had to find a way to cram the bike into his Mustang. I took the whole bike apart, cleaned it, and wrapped it all up and we got it to fit. Then we drove the 1,700 miles back to Tennessee in a car that was pregnant with a motorcycle. The bike has since sat in a million pieces, again neglected. I didn't have enough money or tools to start the build that I had in my mind, and I would not settle for less than my vision. I discovered that Wrenching on motorcycles wasn't a lucrative as I had originally imagined and I needed to go back to school to do something else.

Fast Forward to 2019. I have now moved up to a place in my life where I can start on my Cafe Racer project. In the last 2 years I had graduated from college, and have been working the big job and improving my financial situation. I am finally independent, living on my own with a decent income. I ended buying one of my dream bikes, a 2009 Harley Davidson Night Rod Special (still have the Sportster too). It is a great looking and running bike, in basically new condition. I ride it all over the place. I started to realize the shortcomings of the Night Rod after taking it on The Dragon, hwy 129 (which I live 30 minutes from). The bike has a ton of power and looks great, but a long wheel base and raked out front end don't do much good trying to go through the twisties. Suddenly I had a serious itch to build the neglected Kawasaki that is currently sitting in my crawl space, in various plastic tubs. I needed a bike that was nimble and light. The Sportster is a decent 2 up riding motorcycle with saddle bags and a luggage rack, the Vrod is my baby dream machine drag racing monster, and my KZ will be my light and quick canyon carver.

The Build:
As I stated in the intro, My bike is a 1981 KZ550 LTD. I know that it would probably be cheaper to sell the bike and get something more modern that is faster and yadda yadda, but hey.... what's the fun in that? With this build money is no object. I can fabricate and machine anything I need. The goals for this build are to increase engine performance, overall bike handling, and braking. Essentially try to squeeze as much performance out of the bike as possible. The catch is: I like the vintage styling of cafe racers. This means I wont be upgrading the front forks to USD forks, and I will be ditching the mag wheels for some spoked rims. Listed below are the current plans I have for the build.

Engine:
-GPZ cams
-K&N Pod Filters. (I know the stock air box is arguably the better performing route, but to keep with the trimmed down cafe look, I'm going with pod filters)
-Wiseco 615 Big Bore kit
-Thermal Barrier Coating on the tops of the pistons, Combustion chamber, Valve Faces, and Exhaust port
-Titanium Valves
-GPZ oil pan and cooler
-Custom Exhaust (possibly keeping with a 4-1 exhaust, but I do like the symmetrical appearance of a 4-2. Plus it would keep the bikes weight more even on both sides. I think if i go the route of doing a 4-2, I will have a crossover equalizer tube connecting the headers, which should allow me to have increased scavenging similar to a 4-1. This is one area that i need to do some more maths on. Either way, new custom built exhaust that will be ceramic coated inside and out. This will keep heat in the exhaust gas and reduce the amount that is radiated off the pipe.
-New Performance Ignition Coils (recommendations Welcome)
-New Performance Ignition Wires (recommendations Welcome)

Suspension:
- Progressive Front Fork Springs.
- 17" Warp 9 Supermoto Wheels (I love the spoked supermoto wheels. They should be lighter than the old KZ550 mags. I will probably have to machine a new axle and wheel spacers. On Warp 9's website they have a wheel configurator, but it only has dirt bike models, which makes sense because supermoto bikes are converted dirt bikes.)
- Dual Disc Front brakes (considering getting Brembo Brakes, or maybe sourcing some brakes off of a modern ZX6R I will have to fabricate a mounting bracket to work with my old style forks)
- Rear Disc Brake (Again, I will have to do some fabrication to make a mount for the caliper. Also considering sourcing from a ZX6R or going with Brembo)
- Dual piggy back Fox Shocks
- One potential idea would be to swap out the swingarm to something that is lighter like the Zephyr swingarms. Not sure how much real benefit there would be to this conversion for the headache involved.
- Top Loop Cafe Racer Frame conversion
- Clip ons

Anyways, that's where I am at with it right now. Any advice or input is appreciated. I know that for the money I could easily just go and buy a sport bike, but where is the fun in that. I have no intention of selling the bike and getting something else. I will continue posting updates as things progress with the build. Areas I can see being an issue is with getting the right hubs on the supermoto wheels, and getting those to play well with the brakes and the swingarm/forks and the axles. I figure sprocket spacing isnt a hard problem to fix. The other issue I can see coming up is getting an aftermarket speedometer to work properly.

DoctoRot wrote: .................. I think a decent set of rear shocks will give you more bang for your buck in improving the ride quality than any other mod on a otherwise stock bike.

When I see a vintage UJM with a USD fork and stock shocks/swingarm I just think it looks half assed as the stock rear end has more room for improvement that the front.

Agree! This is certainly true of the 1977 KZ650 bikes. The rear shocks were marginal when new and totally shot before the odometer hit 10k miles. The front forks on mine still work fine with regular maintenance after 62k miles. Notice on the 1977 KZ650 that broke all the 750cc records at Daytona the stock rear shocks were removed and S&W shocks installed. That bike ran 133.7 mph for 10 kilometers; 127.9 mph for 100 kilometers; and 117.1 mph for 24 HOURS. It held the 750cc records for 8 years after which a Suzuki GSX-R 750 set new 750cc records. Ed

I'm new to this forum, and really glad I found it! A lot of good information and resources. I had a friend gift me a 1981 KZ750-E last year that has been sitting outside in southern California for the last 28 years. He was the original owner and logged 34K miles on it before parking it in his back yard. The sun has taken it's toll on the bike, and the insects decided it was a great place to start a commune. My plans for this bike is a resto-mod, with a vintage Superbike theme. I will be using the front end from a 2005 Honda CBR600-RR. After modifying the steering stem, I was able to press the KZ stem into the Honda lower triple clamp. The front end will now bolt up to the KZ frame using stock sized bearings.

Currently I have the bike down to the frame, and the top end of the motor is at the machine shop. Several valves were stuck, so a complete cylinder head rebuild was in order. I was referred to RTC Engineering in Florida during my search for new pistons and rings, and they had a set of 10.5:1 racing pistons left on their "old stock" shelf. This was a stroke of luck, since I was having trouble locating pistons that were 67 mm in diameter. I am debating on leaving the bottom end intact and just going with the top end rebuild.

I am working on adding a swing arm brace to the stock swing arm. The brace will be 1.50" dia. x .090" wall tubing. I made a weld fixture to keep the swing arm straight. I have the tubing bent, but have not started trimming it to fit yet.

531blackbanshee wrote: zx6/636 frontends are common swaps for these old girls.

an 03/04 zx6/636 swingarms can be machined to fit as well and will let you use the zx wheels and brakes .if you wan't to keep your dual shocks the brake caliper bracket has to be modified to "lay the caliper back out of the way of dual shocks.

here is DNel's '78 KZ650 Fighter Project

here is the thread.
kzrider.com/forum/11-projects/520339-dne...er-project?start=160

hth,
leon

Ayyy, that's what I'm looking for right there. Started looking through his thread before o got out of work I'll keep following it when I get home. Think I can piece together a gsxr front end for around 600$ with decent used pieces. A conversion stem from Cognito is around 140$ plus some bearings. I'm going to look at how he did his if I could find a different donor bike I think I could drop the price quite a bit.

The drum frame has the hole for the rear brake pivot point that converts the brake pedal movement to the brake drum lever movement.
Rear disc frame doesn't have this, it has fixings for the rear brake master cylinder. Disc swingarm is also different.
So wouldn't be a straight swop.
Z1000 rear disc.

Z650 rear drum.

What's you use plan? Drag? Cruise? High Speed? Or just to be COOL at cruise night?
Budget dictates it all of course!
Don't go too long!
Try the old Suzuki GS conversion. 160-180 tire is pushing it.
For wide. And cheap, the Kaw ZZX 600? 2004-7. Thee parts are cheap on ebay. Really easy to convert, for 2 shocks like stock
Or have custom built to your specs by "PDM"
Your opening up the worm can / rabbit hole! offsets, frame mods, etc..
Keep an offset of 5/8" at engine.
Good Luck.
Here are a few things I did over the past 10 yrs.

NewYorKZ440 wrote: .................... whats the point in just struts then, like why even bother as manufacturer ? just cheaper ?

I don't think any motorcycle manufacturer ever used struts rather than shocks. I suspect some folks use them instead of shocks because they then can mount the rear wheel very close to the fender and frame since the rear wheel will not move up and down inside the fender or frame. Of course, one big problem with struts is the fact that when going over a bump or pothole the hole bike will jump up and down rather than just the rear swingarm, and this can lead to a serious handling problem especially if hitting the bump or hole while riding around a turn. The other problem is the fact that the jolt from any bump will be transferred to the rider, so some folks using struts mount the seat on springs. If you take a look at the seat in the picture of struts I provided you will see it has springs under it. Ed