1974 KZ400 Cafe Racer Build

ThatGPzGuy wrote: Looking really good CafeChick. Can't wait to see it finished.

Thanks! It's all done aside from a few more heat cycles on the motor, putting another hold-down clamp on the front brake line, putting on the grips and bar end mirrors a new speedometer cable, re-torquing the head and checking all the nuts and bolts.

It runs awesome and growls like a snarling dog with just a little touch of the throttle. I couldn't be any happier with how it turned out. :woohoo:

Very nice.

Came out awesome! Do you know how much weight you shed off of it? Looks nice and light like a proper cafe motorcycle. Should be a quick little bike. Hope you get some riding time in before the weather turns.

KZJOE900 wrote: Came out awesome! Do you know how much weight you shed off of it? Looks nice and light like a proper cafe motorcycle. Should be a quick little bike. Hope you get some riding time in before the weather turns.

Thanks Texas and Joe. I'm not sure exactly how much weight came off, but I can say that it feels extremely light, I mean like "dirtbike-light". Definitely lighter than my husband's KLR650. Just a wild guess, but I don't think this thing is much more than 300-320 lbs. based on the starting stock weight of 387 lbs. I plan to take it to the recycling center in town and ask if I can put it on their scale cause I'd really like to know. I'm buttoning up the rear brakes this morning as well as doing all the other finishing touches and I hope to get my first few test-n-tune rides this afternoon.

: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.