My KZ750 Twin

Finally remembered to start a project page.
My '78 KZ750 twin I picked up for $40.

Started hacking things off to get as light as possible




Made the seat out of a sheet of aluminum and installed a GS1100 alloy swingarm, but just didn't dig the fact that it was 2 inches longer than stock so I went back to the stock arm.

Built the 2 into 1 exhaust and the single carb manifold





Completely rewired the whole thing with new fuseblock, no key, and used a CBR kill switch

The front brakes are dual disc with a GSXR master, but the discs and calipers are waaay to heavy so are getting switched out to drilled KZ650 rotors with Nissin 4 piston calipers from an F4I Honda.
The rear brake is going to be a combination KZ/R6 combo.
THe wheels are getting switched out to 18" front and rear Enkei mags painted bronze.
I really need some good shocks for this thing, but so far she is sooo much fun to ride and this twin makes fantastic torque and sounds awesome. I've got the weight down to 410 right now, but estimate losing another 20 to 30 on the brakes and wheels.

Ill say it again, That bike is hands down sexy. If I can ever get an idle that smooth I would die happy.

I love that seat. I want one just like it. Do you have any more pics of it and what thickness of aluminum did you use? Bike looks killer! ;D

Wow I love to see the KZ love! Your bike sounds like pure sex!

A few questions.

1. So it was stock with 2 carbs and you swapped to one? Did you use a stock carb with huge jets or a larger carb?

2. You dont use any sort of fork stabilizer up front?

3. How comfortable is that seat? it cant be comfortable at all.

4. I still love your bike.

Will McD said:

I love that seat. I want one just like it. Do you have any more pics of it and what thickness of aluminum did you use? Bike looks killer! ;D

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Thanks dude! I think I used .060 but I can't remember for sure. Get whatever gauge you can JUST BARELY bend by hand. I'll take some more pics and post them up a little later.

valvesprung said:

Wow I love to see the KZ love! Your bike sounds like pure sex!

Click to expand...

Thanks!

Fear My Twin said:

A few questions.

1. So it was stock with 2 carbs and you swapped to one? Did you use a stock carb with huge jets or a larger carb?

2. You dont use any sort of fork stabilizer up front?

3. How comfortable is that seat? it cant be comfortable at all.

4. I still love your bike.

Click to expand...

1. Originally it had two BS38 Mikuni carbs, and being that they were in crap shape, I decided to try and run the bike on one carb. Hell, my sportster does it just fine, why wouldn't the KZ? So I used a 40mm CV Keihin Sportster carb. I built the manifold out of some 1 3/4" exhaust tubing I had laying around. I didn't have to make many jetting changes to get it where it is now, she could be just a touch leaner on the pilot circuit, but she runs great so I don't mind.

2. I don't have a fork brace or a dampener yet, but will when funds allow.

3. The seat is not bad actually, but I do have a piece of 1" closed cell foam that sits on the pan. Its just not on there all the time.

4. Me too! Thanks!

Got myself a 750 b1 recently & have been looking for inspiration for a cafe racer conversion & I like the look of your bike . Well done. What forks are you using ? Any uptodate info or photo's available of the project ? Keep up the great work .

I've been thinking about a single carb conversion for a while now, especially after seeing yours.
How's it perform? Do you notice any loss on top end or midrange? It sounds tits too, it that a Harley take-off muffler?
Man....what a cool ride!

Since my first attempted post went south on me, I'll try this again...

Awesome bike! You've definitely inspired me with your twin. Hopefully, I'll get mine up and running soon.

Any chance I could talk you into making a manifold for me?

Swagger said:

I've been thinking about a single carb conversion for a while now, especially after seeing yours.
How's it perform? Do you notice any loss on top end or midrange? It sounds tits too, it that a Harley take-off muffler?
Man....what a cool ride!

Click to expand...

The single carb conversion worked great, it just took up too much room, so I'm going back to duals. Yup, its a Sportster muffler with the baffle cut out and turned around backwards.

tobiism said:

1. Originally it had two BS38 Mikuni carbs, and being that they were in crap shape, I decided to try and run the bike on one carb. Hell, my sportster does it just fine, why wouldn't the KZ? So I used a 40mm CV Keihin Sportster carb. I built the manifold out of some 1 3/4" exhaust tubing I had laying around. I didn't have to make many jetting changes to get it where it is now, she could be just a touch leaner on the pilot circuit, but she runs great so I don't mind.

2. I don't have a fork brace or a dampener yet, but will when funds allow.

3. The seat is not bad actually, but I do have a piece of 1" closed cell foam that sits on the pan. Its just not on there all the time.

4. Me too! Thanks!

Click to expand...

If you are still a member and remember you setting for you sportster carb, I'm pulling my hair out with mine. It's the last part of my build. Could you pass along the jet settings?

Thanks

tobiism said:

The single carb conversion worked great, it just took up too much room, so I'm going back to duals. Yup, its a Sportster muffler with the baffle cut out and turned around backwards.

Click to expand...

I went with a single carb too ...... a 40DCOE Weber ! Could have been made for the job. As you can see, even with the velocity stacks it's still quite compact. Shorter stacks available.

Here's the mock up before I got the various flanges lazer cut. Just waiting to get the tubes welded in.

I'm going Flat Tracker with my project as I'm already building 2 Cafe Racers !

I've had some exhaust stubs made up as well as I want to go with twin hi-level pipes on the left side [ sitting on it ] as the BSA Spitfire scrambler





This is the general look I'm after

Do you still have the carb and manifold by chance?
I'd be interested in buying them.

tobiism said:

The single carb conversion worked great, it just took up too much room, so I'm going back to duals. Yup, its a Sportster muffler with the baffle cut out and turned around backwards.

Click to expand...