KZ400/440 Workshop manual


1974 - 1977 Kawasaki Workshop manual as downloadable PDF files

Page 1-72

Page 73- 100

Page 101-136

Page 137 - 175

Page 176 - End.


1978 - 1981 Kawasaki Workshop manual as downloadable PDF files

Page 1 - 33 Specs and adjustments

Page 35 - 58 Dissasembly

Page 59 - 70 Dissasembly

Page 71 - 81 Dissasembly

Page 82 - 99 Dissasembly

Page 100 - 109 Dissasembly

Page 110 - 118 Dissasembly

Page 119 -129 Dissasembly

Page 130 - 149 Dissasembly/Engine maintanance

Page 150 - 155 Engine maintanance/Fuel system

Page 156 - 170 Fuel system/Engine maintanance

Page 171 - 179 Engine maintanance

Page 180 - 190 Engine maintanance

Page 191 - 216 Chassi maintenance

Page 217 - 242 Electrical - Troubleshooting

Page 243 - 250 Appendix

Page 251 - 268 1979 supplement

Page 269 - 282 1980 Supplement

Page 283 - 317 1981 Supplement

KZ400 H1 (LTD) Supplement


KZ440 Workshop Manual

A workshop manual for the following 440 models can be downloaded from here or here.





Kawasaki Service bulletins

About fixing oil leaks D engine

Air leak problems carb holders D engine

Improved idling D engine

Erratic idling D engine

Lean carburation, unstable running D engine

Erratic idle, carburetor stay plate D engine

440A1, D1 carbs and air box


Non factory manual

This manual can be downloaded as a PDF file here.


Kawasaki workshop manual 1974-1977 models

1974 - 1977 Specifications and tune up page 1 - 22

Disassembly page 23 - 72

Dissasembly page 73 - 100

Maintenance page 101 - 176

Page 177 - End




1977 Z400D4 parts list:

Part 1 Part 2 Part 3



How to tune CB carbs PDF


1974 - 1976 Carbs

How to adjust them, and how they work

1974-1976 Carbs PDF


Cleaning and servicing

I have dismantled the set of carbs I have had on my 400S since I bought it. These carbs has survived 56000 miles, but they do show sign of wear. I have replaced them with a set from a 1976 D3 while I'm servicing them.
The first thing I did was to dismantle the carb rack. This is easy, just screw off the mounting bracket in front of the carbs, and then you can split them.
Then I dismantled the carbs and made shore to sort the parts in marked boxes to be shore to get all the parts back into the carbs where they belong. And I work with one carb and its parts at the time. The next step is to clean the carbs and all the parts. For cleaning I use a method that I have tried out and found very useful. This is the tools I'm using:

A spray bottle of carb cleaner, an old toothbrush, a brush for oil painting, baking powder, and a plastic box. First I spray the carbs with the carb cleaner. Then I put them in the plastic box, it rooms approx 2 litre of water, add 4-5 teaspoons of the baking powder and fill the box with hot water (not boiling hot) till the parts are covered. And it is important that it is baking powder, and not baking soda. Baking soda might discolour the alloy the carbs are made of. Then I let it sit till the water is cold enough to put my fingers in. I use the brushes and brush off the dirt that still sits on the parts. Then I rinse them in hot running water and blow them with compressed air. I also make sure to blow all the passages with the compressed air. The other small parts like screws and jets are getting the same treatment.
This is how the carbs looked, before and after the cleaning

And this is the right side carb with all the parts cleaned and ready for service:

The parts for the left hand carb

This is one of the old pilot screws that I have polished very gently with Autosol, and a new one.

This is the tang on the floats that needs to be bent up or down when adjusting the fuel level in the float bowls.

Also make sure this passage between the main jet and the pilot jet is clean and open. And also make sure that the pilot passages in the carb throat are open. This can easily be checked by spraying carb cleaner into the passage for the pilot/slow jet. And also spraying carb cleaner into the opening for the pilot screw will determine if that passage is open.



First I will mount the linkage that runs between the pulley and the butterfly shaft on the right hand carb.

To get the linkage on the pulley, there is a coil spring and a plastic part that must be compressed with a small screwdriver while pushing the linkage onto the pulley connection. There is a nylon washer and a clip used to lock the connection.

Then I mount the plunger choke on both carbs. This is one area where there can be a problem with a fuel leak if the seal in the bottom of the plunger piston is leaking or an air leak if the rubber seal on top of the mechanism is leaking.

Now I'm preparing to put the carbs together. This is the carbs and the mounting plate. And I have checked that the o-rings that is sealing between the carbs and the plate are ok.

Here I have slipped the balancer screw that sits on one butterfly shaft, onto the butterfly shaft on the other side.

Then I slide the forks on the choke mechanism onto the rods for the choke plunger pistons. Then I can bolt the plate to both carbs.

The next part to get in place is the coil spring that sits between the butterfly shafts on each carb.

Then I check that the linkages and the pulley are working, and I also adjust the choke lever and make sure the plungers are closed when the choke lever is in off position.

Now it is time to put all the other parts back in. This is the float valve seat. I have cleaned it with carb cleaner and a q-tip before assembly.

Starter jet. This jet will very seldom cause any problem, other than if it is dirty.

Needle jet (needle jet keeper). This jet will wear over time, together with the needle, and they must be checked for wear. And if necessary, replaced as a pair. Also check that the bleed pipe holes are clean and open.

Slow jet. Be sure that it is clean, and that the bleed pipe holes are clean and open. And be sure that the screwdriver you are using for screwing in the slow and the pilot jet is clean.

Pilot jet. Check that is clean.

Rubber plug. Check that it is soft and still makes a good seal. If not, it must be replaced.

Main jet. Check that the o-ring is good and makes a good seal. If not replace the o-ring.

Float valve. Check the rubber tip for wear. If there is any signs of wear, it should be replaced.

Float. Over time they will get a bit heavier than when new, but I have never had any problem with them, and since you adjust the fuel level, rather than the float hight, on these carbs, there shouldn't be any problem.

Main jet keeper. Check it is not broken off close to the main jet.

Float bowl. Check the o-ring for the drain screw and the float bowl o-ring.

Pilot screw. I screw it in till very lightly seated, and then out again 1 1/2 turn. That will be a good starting point for adjusting the idle mixture later. Check the tip of the screw for signs of wear or damage. If any damage, it should be replaced. And on the picture I have fasten the idle speed adjustment screw on the correct place in front of the float bowl.

Then the air jets. Again be sure the screwdriver is clean.

Make sure the air jets are mounted correctly. They have different sizes.

Air jet cover and gasket

Piston cap gasket and piston. I have already mounted the needle to the piston. Since there are no notches on the needle, there is no adjustment of the needle height.

Piston cap

And then I do the same thing with the other carb. And finally both carbs are ready assembled. The carbs are now ready for a bench synch. The adjustment of the fuel level in the float bowls (float height adjustment), adjusting the idle mixture, and the final balancing of the carbs will be done after the carbs are mounted on the bike.


Rebuild kits

Rebuild kits for these carbs can be bought from , and they are made by Keyster, kit no KK-0139.

This is what one kit contents:

I bought two of these kits and made some measurements of the different parts and compared them with the stock parts in the carbs I have. And I have also been testing these rebuild kits in my carbs, and they don't work well in the 1975 and 1976 carbs I have. I have now used them in my 1974 carbs, that is the carbs they are made for, and they still don't work well.
There is a difference in the the slide cut away between the early 74 model carbs, and the later 74-76 model carbs. The pistons in the 1974 carbs have got a cut away in the slides that the 1975 and 1976 carbs don't have, allowing a larger air flow through the carb throat, and creating a different under-pressure. And because of this, the needles used in the 74 carbs are longer because they are mounted higher in the 1974 pistons than in the other pistons, and they have a different thickness and a different taper than the needles used in the later carbs. And shimming them will only create more problems.
Also the needle jets is larger, and the needle jet bleed pipe have got more holes than the one used on the later carbs. Also the 40 slow jet and the 110 air jet was not a good combination for the 75/76 carbs.
With the 40 slow and 110 slow air jets, the idle was a bit crappy with the 75 and 76 model carbs. Changing these jets back to the stock 35 slow and 90 slow air jet solved the problem.
Acceleration from 4500rpm was ok, and the full throttle performance was good.
The real problem is an annoying erratic running caused by a rich mixture at cruising speeds below 5000rpm. And it got worse the lower down in the rpm range I got. At 3000 rpm it was a pain to ride. Altering the float height, the pilot screws and the main air jets did not help. And it made no difference if I took out the air filter.
And the reason is the longer and different needles, and the different needle jets. I swapped back to the stock needles, needle jets and main air jets, and the problem was gone.
Totally, I have been riding approx 600 miles while testing these carbs.

And are these kits worth buying?

For that $$ you are getting new pilot screws with the coil spring and o-ring(no washer though), new float valves with seats and o-rings, new 135 main jets with o-rings, new float bowl gaskets(o-rings), new air jet covers and gaskets, new vacuum piston cap gaskets and new o-rings for the float bowl drain screws. The parts I have listed above can be used in all the 1974-1976 carbs. The rest of the parts will be a trial and failure issue.
And compared to the price you would have to pay for some of the parts if you buy them from BikeBandit, it is a good price. However, the float bowl gaskets I got in the kits I bought did leak though.
But these kits will most likely not solve the most common problem with the 74, 75, and 76 model crabs; witch also is the problem I have with my crabs, worn needles and needle jets. This problem is most noticeable when you open the throttle fast for acceleration. The mixture will be too rich as the pistons and the needles rises, and the acceleration will slow down. Also the fuel consumption will be higher as the wear on these parts increases. I have also been able to compare the used crabs, and how the rebuilds kits works, with a new set of crabs that I found in England this spring. And the difference in how the bike runs is huge. This has made me believe that the jet needles and the needle jets in the aftermarket kits are of low quality, and very inaccurate sized.

If you buy these rebuild kits, don't throw away the old parts, you might need them.

Maybe it is possible that the same company can make parts for the 75 and 76 carbs if they get parts as a pattern? I'm not sure if they can get the needle and the needle jet right though, if the ones they get as patterns are badly worn.

Klasmo Bikes still have stock parts for these carbs.

This picture shows the difference in vacuum piston cutaway between the 1974 carbs and the other model year carbs and explains why the needle and needle jet is different. The 1974 carbs to the left.

Shimming needles on the 74-76 model carbs

If there should be a need to raise the jet needles on the early model carbs, this is possible by using shims. What's needed is 0,5 thick washers with an outer diameter of maximum 6,5mm and a inner diamter of at least 3,2 mm. Washers for 3mm machine screws should fit the purpose. What's important is that the jet needle don't get "locked" in one position by the jet needle holder, but still can "float" in it's seat in the piston as with the original set up. This can be achieved by using Loctite on the jet needle holder threads, then after the jet needle and shims are in place in the vacuum piston, screw it carefully in till it stops against the head of the needle, then screw it out 1/2~3/4 turn. The Locktite will lock the jet needle holder in that position and ensure that jet needle still can move freely in its seat in the piston. If not, there will be some excessive wear on both the jet needles and the needle jet. Always start with one washer and try how it works. The maximum washers that can be used are 3, or 1,5mm. The reason for this is the shape and depth of the seat for the jet needle head inside the vacuum piston.


1977 KZ400D Carbs


KZ400/750 Simple Service

As PDF file.

Balancer service

As PDF file.


Ignition coil - Replacing plug wires

Ever wondered how the plug wires are attached inside the ignition coil? The coil on my bike started to act strange this summer, and I replaced it with a spare coil I had.

Then I found that one of the plug wires was loose, and since the wires seems to be moulded into the coil, they also seem to be impossible to replace. I pulled out the plug wires and had a look down the hole. It looked like there was a spike in the bottom of the hole, and that the plug wires simply was posed down in it, making shore there was good contact between the spike and the inner cord of the plug wire. And the only moulding done was around the opening of the hole, making sure to secure the plug wire, and making the connection waterproof.

I then placed the coil in a vice and cut off the top of the tubes for the plug wires. I made sure to cut it off above the spike in the bottom.

From the side:

From above:

And this is how the plug wires are attached:

And this is how it looks when the coil is in one piece:

Here I have started to replace the plug wires. I have made sure to cut the insulation 2mm shorter than the steel core to make sure there will be a good connection.

This is the plug wires I'm using. A silicone wire with a steel core.

Here the wire is pushed onto the spike.

Then I made sure that the piece I have cut off fits.

Here the piece is glued on to the coil with epoxy glue. And I have prepared the next piece and plug wire. I'm gluing one piece at the time since I have to work pretty fast with the glue I'm using. It starts to harden after 3 minutes.

The second plug wire is in place and the second piece is glued to the coil.

Finally I put on some more glue to be sure to fill all cracks, and the opening around the plug wires, with more glue to make sure everything is waterproof. It is not the prettiest job I have seen, but it is far more important that the joint is waterproof than pretty.

Here the plug wires are cut to the correct length and the plug caps are mounted. I have kept the wires longer than the stock wires, and the plug caps I have use are a non resistance type that needs to be soldered to the wires. These caps are originally made for marine engines, they are made out of silicone rubber, and they are waterproof. I have also put on an extra layer of silicone sealer around the plug wires and where they go into the coil.

I'm sure the method can be improved though. And now that I know what's in there I won't have to use the hacksaw and cut it open another time if I'm going to replace the wires in another coil. It should be possible to pull the old wires out, bore out the first 1/2" of the tube, and push the new cables back in and just use some glue or silicone sealant around the tube opening to keep the wires in place, and to keep everything waterproof.

NOTE : My coil seems to be fine after the plug wire replacement, but anyone who tries this out is doing it on his own risk, but the way the wires are connected from the factory is very simple. And the pieces that I have cut off can easily be glued back on with epoxy glue.

New plug wires can also be spliced on the old wires outside the coil. If you cut off the old wires approx 3 inches / 7~8cm from the coil, new wires can be spliced on by using NGK HT cable splices, or by soldering the new and old inner cord together and secure the splice with silicone and a heat shrink tube. There is a downloadable document about it here. I used this method the last time I replaced the plug wires on this coil, and it worked for 8 years/ 38 000 mile without any problem. When I got trouble with the plug wires this time, it was because they came loose inside the coil. The splicing was still as good as when I spliced the wires.


Starter motor

This is a 400D3 starter motor that I have dismantled for checking the starter gear housing and the carbon brushes. I have also re-greased the starter gears. I have not dismantled the starter completely since it has been working well, but it is possible. The workshop manual has got a parts diagram that shows how it's done.

The first I remove is the circlip for the starter gear shaft.

Then I have removed the 3 shims behind the circlip

The two Philips screws that are used for bolting the starter assembly together are removed.

Then the starter gear house can be taken off. The starter gears are lubricated with grease, and I have cleaned off the old grease and re-greased the gears before assembly.

Here I have taken off the end cover with the bushing (bearing) for the anchor. On this starter there are two shims used between the anchor and the cover to make shure the end freeplay is correct. The number of shims used will vary.

There was an amount of carbon dust inside the cover and on the mounting plate for the brushes. I cleaned it off with mineral spirit. Then I measured the length of the carbon brushes. New, they should be approx 11mm long, and the service limit is 6mm. These were 8~9mm, and I decided to use them for a while longer. If they had to be replaced, it is easy to do so. Just screw off the clamp for the wire for the brush, then bend the pressure coil spring outwards and pull the brush out, hold the spring in that position and enter the new brush and let go of the spring. Then fasten the wire. Repeat for the other brush.

When assembling the starter, look for these marks on the covers and the starter body. They should line up.




Testing the KZ440 electronic ignition system

Here you will find a test procdure for the electronic igniton system on the 1981 and on KZ440 models:

About wheels and replacing wheel bearings PDF

1974-1977 Oil pump

This is how I place the bike when I'm working on the clutch. Or in this case the oil pump. Doing it like this allows me to take off the primary cover without draining the oil.

To get to the oil pump, the clutch as to be removed.

Here the oil pump is dismantled.

And here I'm putting it back together.


Cleaning a 400D cylinder head

Here I have cleaned a 400D cylinder head and lapped the valves and seats in carefully to clean the valve seats and the valves to insure there is a good seal.

The combustion chambers and the valves have been cleaned.

And the valves and the valve seats looked very good, no signs of burning, so I decided to lap them carefully for a final cleaning. The tools I used for lapping in the valves can be bought as a set in most auto stores. The box with lapping compound contains both a course and a fine compound. I started by lapping gently with the course compound, and to make sure I didn't overdo it, I took out he valves and wiped off the compound and checked the valves and the seats often. I only lapped till the seating surface had a light grey narrow circle. Then I cleaned off the course compound with mineral spirit and did the final lapping with the fine compound. And again I stopped and checked the surfaces often and made sure I didn't lap them too much.

This is how the seat looked before the lapping.

And this is how it looked after the lapping.

When the lapping was done, I cleaned the valves and the valves seats thorough to make sure the entire lapping compound was removed. This is very important. Then I replaced the valve stem seals, and installed the valves with the springs and the keepers. Finally I leak tested the valves by pouring mineral spirit into each intake and exhaust port and let it sit for a while and then checked if the combustion chambers were still dry.. Luckily these were tight, but if there had been a leak on any of them, they would have to be lapped a little more with the fine compound and checked again.



1974 KZ400 Carbs


Parts catalouge KZ400 1974-1975 European market

Parts catalouge KZ400S