1981 KZ400 J2

Hello!

I am new here

I have just bought an 1981 KZ400 J2, and I have tried to research the internett for information about this bike but I have had little luck.

I have figured out that this one has a inline four engine, and most of the KZ400 have a inline twin engine...!

Anyone got some usefull information? Or pointers to webpages or good threads?

Sorry if this topic has been discussed before...

No eBay APP ID and/or Cert ID defined in Kunena configurationWhere are you located?

The KZ400J bikes were a Japan-market bike. Most of the world got the same bike as a 550. In fact 90% of your bike will be the same as the KZ550A/KZ550D type bikes.

There are some differences though. Even though the motor is basically the same as the 550, obviously there are differences. Pistons, valves, cams, possibly the gearing etc., are different. The brakes are likely different as well. Most of the Chassis, otherwise, is the same. The carbs, even though they look like the 550 carbs, are slightly different. The 550's use the TK-22 carbs. I believe the 400J uses TK-21 carbs.

If you have access to 550 motors, they should bolt right in and are far more common and available. But if teh 400 motor is in good condition, I'd keep it just for the rarity. If you are in Japan, then it's not so rare. I remember seeing them quite abit even in 2005 in Japan.

In My signature you'll find an online manual for the 550, but much of it will apply to your bike.

Regarding valve timing, you would want to read this site:
Valve timing info

Pay attention to the warning about the cam chain tensioner and valve cover issue.

You'll want a manual like this one. Notice the bike on the cover should look like yours. There are later ones with single-shock models on the cover.

Hey,

Thank you for the tips.

I am in Norway, but I do not know where the bike originally came from. I bought it as a no runner, and I am going to try to get it fixed up. Getting a 550 motor sounds like a good plan. Will the 750 bolt right in as well or is it more work?

The 650/750 will require cutting and welding the frame. The 80 through about 83 550 A, C, D motors should fit right in. Later 550 motors will just require minor changes in the engine mounts.

Okay,

Started dismantling the bike today. It was a pain removing the carbs and then the air box. Very tight. Is it possible to run pod filters on these carbs?

Altso, I have never worked on the TK21 carbs, and I am looking for some kind of guide. Anyone got it?

The engine turns over, so now I am going to clean the carbs, reinstall them , get new gas and plugs and try to fire it up. I opened one of the float bowls and I was some gunk there so it needs a cleaning.

Hello bbolstad...did some minor reading and found the Z400J1/J2 were marketed (outside of Japan) in Europe and South Africa. Any parts unique to this bike will be in Europe and not on this side of the Atlantic.

Thanks Mcdroid, I didn't know the J's made it out of Japan. (But I should have known since the chart even says "West German".) :blush:

bbolstad wrote:

Okay,

Started dismantling the bike today. It was a pain removing the carbs and then the air box. Very tight. Is it possible to run pod filters on these carbs?

Altso, I have never worked on the TK21 carbs, and I am looking for some kind of guide. Anyone got it?

The engine turns over, so now I am going to clean the carbs, reinstall them , get new gas and plugs and try to fire it up. I opened one of the float bowls and I was some gunk there so it needs a cleaning.

They (the tk-22 which I think are almost identical) respond well to pods. They are not CV carbs, so the air filter restriction does not affect the slide movement.

Jets are not easy to come by, though. There is a Dynojet kit which has a really nice needle with a different profile. The jets that come with it may be too big for the 400, though.

If you can't get 400J rebuild kits, I will bet 550 A, C or D rebuild kits will work well. There are good ones from K&L (18-2462) and Keyster (KK-0049). The kits are almost the same. They come with #92 mains, #32 pilots and adjustable needles for the TK-22 carbs which have a different needle from your TK21 needles.

The choke is somewhat over-simple so it needs some playing with to get the cold start worked out. Here is a mod for making the fast-idle adjuster more easily accessible.
home.comcast.net/~loudgpz/GPZweb/Carbure...PZchokeScrewMod.html


Here are some details from the factory manual regarding the settings.

Looks like your pilot jets are the same as in the tk22, and your mains are pretty close to the 92 in the standard 550's. You could probably use jets from the 81 KZ550D1 gpz. They were 94's. You could also drill them as necessary. I find with pods and an aftermarket exhaust, it really helps to up the pilot jets to 34 or maybe even 37 (but this is on the 550 gpz's). You will probably want 94 or 96 mains. Some small-head keihin jets may work.

On the chokes, make sure all of the little flapper valves are in good shape on the choke plates. They sometimes fall off. Make sure all of the hinge pins are fully seated and the springs are all in place. Without that, it can be hard to start. Some people have completely sealed off the choke flaps and just use the choke plates as solid chokes which mean you have to manually control the choke lever while starting. It's one of things where it's easy to start once you know the trick.

Dismantled the lower part of the carbs (where the fuel is). Quite alot of crust but I used cleaners and compressed air and got it quite good. Did not dismantle the top, but the chocke flaps looks good.

Also drained the tank. Will have to mount a inline fuelfilter I think. Checked if the old plugs had sparks, and they did. Mounted a battery and tried to fire it with no air box, but no luck. I did fire a couple of times, but then died.

Bought some new sparkplugs tonight (probably smart, since the old one been sitting in the bike since 2005 atleast).
Will try again tomorrow.

Here is a pic of the bike when I got it btw.
It has koni rear shocks but one of them is lacking the preload adjuster ring. Wonder if I can get just that...

Wow you learn something every day, A four cylinder 400 Kawi. I thought Honda was the only one with the 400four. Nice bike by the way

Got spark, got fuel (judging from the plugs, they are all wet), not starting. hm.

Kawickrice wrote:

Wow you learn something every day, A four cylinder 400 Kawi. I thought Honda was the only one with the 400four. Nice bike by the way

Kawasaki also produced a 250 four cylinder between 1989 and 1997 (ZR250)...not sure where that was sold.

Running now, forgot to hook up the hose going directly to carb no 4. Was running it without airbox, not very good idle. Think I will go with the pods, the airpox is a pain to install.

Also experienced some knocking from the engine when it was idling under 1000rpm, but it went away when idling it at 1500rpm.

Anyone know valve clearances on this bike?