1974 KZ400 Cafe Racer Build

:woohoo: I just got back from my first test ride; 15 quick miles on the winding, twisting backroads of rural northern Jersey. The bike is light as a feather, handles beautifully and sounds great. The riding position is a lot more comfortable than I thought it might be. Going from a 15T counter shaft sprocket to a 17 was spot on. The VM32s are just about perfectly tuned, but they need slightly bigger main jets for the motor to reach its full potential. I didn't do a plug chop, but I can tell it starts to want more fuel than it's getting at about 8500RPM. Here are the specs if anyone is interested or in case it helps someone else down the road:

Standard Bore, Stock Cam, Stock Ignition, Very Mild Porting & Smoothing
NGK B8ES Spark Plugs Gapped .030”
93 Octane Sunoco Fuel
Timing and valve clearances set to FSM specs.
Carbs: Mikuni VM32
20 Pilot Jets
200 Main Jets (210s should be the ticket.)
2.0 Slide Valves (The 3.0 slides that came with the carbs gave it a “lean stumble” at 1/8 throttle. The 2.0 slides cleaned that right up.)
6DP17 Needles, Center Clip Position
23mm Float Height
Air/Fuel Mixture Screw – 1.75 Turns Out From Lightly Seated
UNI Pod Filters (lightly oiled)

Just Fantastic. I'd like to hear it...

ThatGPzGuy wrote: Just Fantastic. I'd like to hear it...

Thanks! I'll do a video once the 210 mains get here as well as the 4 new valve adjuster caps I had to order. At the end of my second test ride yesterday, I pulled back into the driveway and when I came to a stop, there was just a hint of smoke coming off the left front pipe and the dreaded smell of burning oil. My heart sank. I immediately shut the bike off and set out to find the leak. Turns out that 2 of the valve adjuster caps had cracked. One worse than the other, and it must have gotten a spritz or two of oil on the pipe. I was so relieved to see that it was something so simple. Other than that, the bike hasn't leaked a drop of oil anywhere.

Interesting note about those aluminum caps: I know I torqued them to spec and used the correct o-rings, so they didn't break due to over-tightening. When I looked them up on Partzilla, it turns out that Kawasaki has an updated part number for them, so I imagine they used some bad materials in the originals and eventually updated/upgraded them. Or maybe the aluminum just gets "tired" after 1000s of heat cycles. Anyway, here are some pics.

very tastefully done .
you should be proud.
thanks for posting,

leon

531blackbanshee wrote: very tastefully done .
you should be proud.
thanks for posting,

leon

Thanks, Leon. I'm thrilled with it! The only thing I'm not thrilled with is the rear brake. I wasn't expecting much since it's a drum, but a 300 lb bike with a 130 lb rider should stop a lot better. I'm starting to look into a rear disc conversion and so far it looks like the rear rim and brake set up from a late 70s KZ750 might be do-able.

Sounds suspect that the two valve adjuster caps should break on you around the same time. Is it possible that the torque spec is wrong in the manual? What manual are you using? Reason I ask is that on my KZ900 I stripped a cam chain adjuster due to wrong torque specs information from a Clymer service manual Others have stripped cam cap bolts for similar erroneous torque postings. Not sure if there are any service manual errors out there for your bike. But just seems suspicious that they broke like that. The factory service manuals seem to be okay for these other models I mentioned. So if you are using the factory manual then I would say you are good. Just food for thought to consider.

Yup, it's the original factory service manual with the blue cover. One of those caps was broken when we got the bike, so I had ordered a replacement back then. It was the updated part number, so I just ordered 4 more of them and will only replace the 3 that are known to be originals and I'll keep the 4th new one on hand as a spare. This time I'll just snug 'em up and use a smidge of loc-tite and see how it goes.

If you really want to improve braking, look to the front. That is where about 90% of the braking action happens. I use the rear brake rarely. Usually to settle the chassis going into a turn, or if I am slowly negotiating a really slick surface like wet grass.
Two up touring, yes a little rear brake, otherwise I just punish the front.

I like it. Classic cafe with just a little modern twists.

I like how you used inverted bars instead of clipons. Clubmans or Aces would look great too but might not be as comfortable.

I like how you stuck with the double pipes instead of going 2-1 too.

Lets see it from the front with that healight.

One issue i see is without something in front of the rear tire yo are going to fling crud at your pods and engine like crazy. You should put up some sort of shield or a half fender to protect them and jsut to keep things from being a royal mess.

TexasKZ wrote: If you really want to improve braking, look to the front. That is where about 90% of the braking action happens. I use the rear brake rarely. Usually to settle the chassis going into a turn, or if I am slowly negotiating a really slick surface like wet grass.
Two up touring, yes a little rear brake, otherwise I just punish the front.

I couldn't agree more....

TexasKZ wrote: If you really want to improve braking, look to the front. That is where about 90% of the braking action happens. I use the rear brake rarely. Usually to settle the chassis going into a turn, or if I am slowly negotiating a really slick surface like wet grass.
Two up touring, yes a little rear brake, otherwise I just punish the front.

Thanks for the tip, Texas. The front brake works great, so that's not a problem at all, and I do use it a pretty good amount, but I was talking about coming to a stop from 60mph. I was just expecting the rear brake to be a little more powerful than it is, even though it's a drum. I've ridden plenty of drum brake bikes and most, if not all, had better rear brakes than this. No biggie. I'll either get used to it or find a disc conversion.

GPzMOD750 wrote: I like it. Classic cafe with just a little modern twists.

I like how you used inverted bars instead of clipons. Clubmans or Aces would look great too but might not be as comfortable.

I like how you stuck with the double pipes instead of going 2-1 too.

Lets see it from the front with that healight.

One issue i see is without something in front of the rear tire yo are going to fling crud at your pods and engine like crazy. You should put up some sort of shield or a half fender to protect them and jsut to keep things from being a royal mess.

Thanks for the kind words. There's a pic up above from the front that shows the headlight. For whatever reason, the photo turned sideways even though it's straight in the photo album on the computer. I wound up mounting the headlight upside down for two reasons. One is the wire hole is positioned better that way and the main reason is that I'm using the little high beam indicator as a sort of safety light that shines down on the front fender, similar to the 2 LEDs that I mounted up in the frame at the rear that point downwards at the rear hubs.

Good point about a shield. My original design had an aluminum "screen" if you will, mounted to the rear of the triangle. I'll keep my eye on it. If the rear of the motor and the pods get all nasty, I'll do the screen idea.