1975 Kawasaki kz400s Cafe Racer

[bonzer78]

Hello everyone.

I bought a 1975 KZ400s back in August and have been slowly building a cafe racer. I bough it for $375, in pretty rough shape, from some guy's shed. The main problems, at first, were that it was ugly, had a terrible seat, and had a bent kickstart lever. However, as I got into it I realized that the carbs were too corroded, and were missing some parts.

So as I saved up for a brand new pair of carbs, here's what I did.

After completely disassembling the bike, I:

Frame
• Cut off all tabs for the airbox, seat mounts, etc.
• Stripped the paint, grinded and sanded off any rust, and smoothed out rough spots and factory welds. I also cut off the long spars (?) that held the rear fender and turn signals.
• Fabricated a loop for the back of the frame, welded that on, as well as new seat brackets, then grinded all the welds smooth.
• Had it powdercoated black.

Engine
• Cleaned, and cleaned, and cleaned.
• Did a tune up (didn't need a rebuild, as it only has about 5800 miles on it)
• painted the cases with high temp engine paint (a sin to some, i know)

Body
• Grinded and reshaped the top triple clamp to remove the old handlebar mounts and one of the instrument mounts. Surfaced and drilled the top to accept the key switch.
• Fabricated a mount for the speedo.
• Fabricated a bay of LEDs for the indicator lights.
• Chopped down the front fender.

Other
• Replaced original carbs with new Mikuni VM32's from Sudco
• Mounted a pair of vintage-style Firestones from Coker
• Polished original rims
• Rerouted all wiring
• Wired small toggle switched on the handlebars. Originally I had routed these into the handlebars, but I kept having problems with them, so I simplified it.
• Installed clip-on handlebars with GT grips

Currently underway
• Having the custom seat upholstered
• Getting the bike running right

To come
• Paint the tank
• Buy or make and install rearsets
• Buy and install reverse megaphone mufflers
• Buy and install turn signals, brake light, and license plate
• I need to fabricate a longer kickstand

--
I always had a pretty clear vision of what I wanted this bike to look like, and I think it's coming together very well. You have to see it in person to see some of the details.

Pictures to come.

 

[bonzer78]

Here's what it looked like before I bought it:

 

[teddpage]

Awesome...sounds like you've done a lot with it! Cant wait to see some updated progress pix!!!

 

[noahdog]

It's always good to have another KZ400 owner around here. I always enjoy seeing other people's mods and ideas for cafe racers.

 

[bonzer78]

Cool, thanks guys.

Here are some photos of the frame mods.

First, after sandblasting, cutting off all those extra tabs, welding on the frame loop and new seat mounts, and after grinding down the factory welds:

Then after powdercoating:

This was back in December. After that, I started reassembling everything. Assembled pics next.

 

[bonzer78]

Here are some photos after I put everything together again for the first time since I bought it. This was in January, after I got my carbs, and got everything back from the powdercoat guy.

At this point I didn't have the headlight in, exhausts installed, seat, etc.

But this was my first chance to get to see what it looked like. I had done some mock-ups before I had everything powdercoated, but that was when I planned on doing a solo seat. I since changed my mind and went with a simple two-seater set-up, similar to what you could find on some of the wrenchmonkees or deus bikes.

Here's a close-up of the triple clamps. I took these photos at night (obviously), so you can't see it in great detail, but I ground down the stock handlebar mounts and made a custom mount for the key switch. I also made a custom mount for the speedo (which I plan on swapping for the tach when appropriate), and custom made the little bracket for the LEDs.

 

[interceptor]

Damn, this bike is looking killer. Great job on the rear loop! In your pics, it looks like the rear tire is bigger. (At least to me it does.) I like how this bike sits. Did you make the bracket for the idiot lights/idiot lights? Can't wait for more pics.

 

[bonzer78]

Thanks!

On that rear loop, I took the tubing to a fab shop and had them bend it for me. It was $60, but I think it was worth it. Then my brother-in-law and I welded it on, and I spent forever grinding down the welds and blending it in.

And yes, I made the brackets for the idiot lights. I ordered those LEDs online, drew a template on the computer, drilled out the holes, and then had that same brother-in-law cut out the outline on his bandsaw (he's a machinist).

Speaking of those LEDs, I'm having trouble with a couple of them. The neutral light barely lights up only when the bike is running. And the brights light doesn't work. Any ideas? I guess I'm going to have to take them out and troubleshoot. It's going to be a pain, because I've got waterproof heatshrink tubing around them all to keep it all sealed from the elements.

 

[rextec]

wow shes a beuaty!!! love the tire combo, really makes the bike. i will be doing something similar to my yamaha ds6.

 

[bonzer78]

Thanks rextek!

And interceptor, I forgot to respond to your comment about the rear tire looking larger. The rear is a 4.50x18, and the front is 4.00x18. The rear just sits surprisingly taller for being only .5" wider, and on the same size rim.

I love the stance of it though. I'll post some more pics soon — I should have my seat this week!
And I got it running, but I'm waiting on a new throttle cable. The cable I was sent was wrong and was holding the throttle almost half open.

 

[hurley209]

great bike man, props

 

[interceptor]

Again, looks great. I know there are some guys here that know ALOT about LED's. Too bad about the throttle cable, but starting it and hearing it run probably offset that little glitch.

 

[madmart]

Looking good my friend, possible BOTM !!!! Ive got a KZ750b that is very slowly taking shape, will post pics later. Keep up the good work.

 

[bonzer78]

Thanks again!

Here's a little video taken with my iPhone. Remember, I don't have the throttle cable, as I'm currently swapping it out. But it runs!
***IT RUNS!***
This has been a long time coming.



I don't know what's up with the photo under the video. This is the only way I could figure to upload the video, through photobucket.
After watching this, there's a few things I need to point out:

The footpegs on there are just placeholders. I'm going to mount rearsets as soon as I get the seat on, so I can get a more actual idea of where they need to go. I'm going to be making a longer kickstand, so I don't have to use a block. And that tank obviously isn't final. I wanted to get it tuned and running before I worried about ruining a paint job. I think I'm going to go with black and silver. I can't decide yet.

 

[bonzer78]

Oh yeah, and I still need pod filters or velocity stacks, mufflers, etc., etc., etc.

Lot's of little work to do, but the big thing has been getting it started, and now I'm there. I can't tell you how many little problems there were. First it had bad carbs, then when I switched out the tank (if you look at the photo of when I bought it, it wasn't the right tank, it was small) I realized the petcock didn't fit. Then the search was on for the right petcock, after which I found a certain year CB550 or 750 was a direct swap. Then I had no spark. Now the throttle cable was too short (which I should have been able to figure out w/o the engine running, but alas...).

Anyway, almost there.

 

[arcspeedworks]

Killer job there! I love the gauge modifications you done. It sure is nice to see more KZ's around DTT nowadays. I will definitely be watching your build as you progress.

 

[valvesprung]

HOLY SHIT! This is going to be single best KZ400 ever built (until I build my next )

Seriously spot on work and the styling is perfect...

 

[dakine_surf]

Nice build, I will say this however, I think you are going to have huge problems with the rear hoop. Without any weight the clearance is minimal, and once you are on it, I can't imagine it not rubbing over every bump in the road. even on smooth roads the rear suspensions is working pretty hard. Unless those shock have less than 2" of travel I see bad things in the future. I am not trying to be negative or anything, but i mad a similar mistake when I was 15 or so... then I proceeded to just say f it (who cares about a little rub) which ended with me in the hospital. Just don't want to see you get hurt, thats all.

Cheers,
Dakine

 

[hurley209]

I hadn't paid attn to that but dakine is right, as soon as your suspension moves it's gonna hit, something you don't want happening at 60mph, could be very bad, if you wanna keepthe hoop I suggest extending further back so that the tire can travel through it without any interference, or add an upsweep angle to the current hoop to give the tire enough clearance. Your build looks great tho! Were just trying to keep you in one piece.

 

[bonzer78]

Thanks for the props guys, really! I'm stoked.

Regarding that rear hoop — yeah, I hear ya. When I built it I had the stock tire on here, which was much thinner, and didn't sit as tall. When I put these Firestones on I couldn't believe how tall that back one sat, and how close it came to the frame loop. Currently there's only 1.25" clearance between the tire and the bottom of the frame. I'll take another look at it tonight, but let me run a couple alternatives by you guys:
• I've been thinking about swapping the rear shocks for some new ones. The current ones are 12.5", and I could go to about 13.375". That would give me just over 2" of clearance.
• That 4.5x18 rear tire has about 4" of profile, while the 4" on the front has 3.5". If I swap the rear tire for a 4", that should give me another .5" of clearance. Combine that with the longer shocks, and I'm looking at about 2.5", or double what I have now.

Or I extend that loop. But my seat is custom made for the size my frame's at currently. If I change the frame, I'll have to get a new seat made. $$$. Now, even if I extend the loop, the tire would still rub on the bottom of the seat when it bottoms out. But I guess that's not as much of a problem?

Another note: I'm 5'8", about 145lbs. When I sit on this bike now that suspension barely moves. I know it will on the road obviously, but I just wanted you to have an idea what I'm working with — I'm not huge or heavy, so I'm not as taxing on the suspension as if I was 200+.

And dakine, I don't take it as negativity — I appreciate the input. That's why I'm on this forum, for the shared expertise.