Kawasaki Motorcycle Forums banner
1 - 18 of 18 Posts

·
Registered
Joined
·
21 Posts
Discussion Starter · #1 ·
Original Keihin carbs. Replaced diaphragms, float needles, main jet needles. Cleaned and hot soaked many times. Made custom intakes to replace crappy rubber carb boots. No leaks.

Originally it wouldnt idle w/out partial choke. Died on throttle.

Will idle and run better if I cover the carb intakes slightly w/ my hands.
I have original airbox which is not in.

In order to put airbox in , rear wheel needs to be removed.

Do these bikes run better w/ airbox attached ?
 

·
Registered
Joined
·
48 Posts
Great to see another 440 back on the road. I have the 81kz440 chain and after it sat for many years haveit running. To get it running I had air box in but no fllter. After first running and warm up I put it all back to origianl with filter in. It ran better and better as it cleaned itself up. Without airbox and filter it may be getting too much air. Keep an eye on the plugs. These bikes are also cold blooded so let it warm up before trying to many changes.
 

·
Registered
Joined
·
21 Posts
Discussion Starter · #3 ·
Ok thats what I thought. Looking at this massive airbox, theres a good reason why engineers designed it that way. This is a B2 model 2:1 exhaust, flat seat, wire wheels, chain, basic model.
Something isnt right, doesnt have the stripes on the tank and side covers. Theres a gap between the seat and tank.

Shed purchase in June.
140 psi compression.
 

·
Registered
Joined
·
21 Posts
Discussion Starter · #5 ·
Re: '81 KZ440 Installing Airbox

This bike came w/ 2 halfs of airbox. Seems le boucher (past owner), cut it half to remove. Purchased one from auction.
I found no info on the installation of airbox.
So here goes.
1) Remove seat.
2) Remove side covers
2) Disconnect neg bat. Disconnect pos. bat.
3) Remove Bat w/ box and let rest on upright footpeg.
4) Remove regulator assmbly w/ bracket. Let hang on side of bike.
5) Loosen chain adjusters.
6) Remove rear axle nut.
7) Drive rear axle out.
8 ) Remove rear wheel, let chain hang loose.
9) Remove inner fender cover.
10) Bend the forward inner fender cover bracket down. There are 2 to a side welded to the frame, in which the fwd part of fender slides between.
(I could not manage to slide the airbox in w/out doing this.)
11) Slide airbox in w/ the fwd(intake to carb holes ) pointing up. Then once past a certain point, flip box toward carbs.
12) Push the rubber box boots on so that the sealing groove is place. You will have to use a screwdriver to work it in
There is a small cutout where the boot is flush w/ the box. Align this w/ the tiny pin that protrudes from the box.
If not, the airbox boot will be misaligned w/ the carb.
13) Start pushing, banging the airbox toward the carbs. Start the 2 upper box L brackets w/ bolts and slowing draw the box in.
My boots didnt quite line up and were half going on. I had to use a cotter pin puller and go around to start the boot lips on.
14) Tighten box L brackets in.

After 3 months, the bike ran better and will idle w/ no hesitation. Took awhile to warm up though, its 40F.
Found a vacuum plug on the carb(there 1 for each to plug a vacuum port for syncro) w/ minor hole and replaced.
I was also getting some vac leak at the throttle shaft. Sprayed carb cleaner to ck. After the second spray on shaft, it miraculously smoothed idle and stayed that way. weird.
My idle mixtures screws are out 3 turns.

Having owned as many as 25 diff bikes in my life, these 81 KZ440 carbs are not engineered very well. This might be due to the haphazard onslaught of pollution controls back then . Also, I think it would be a poor running candidate for a cafe style bike w/out a complete carb retro.
 

·
Navy Vet Search & Rescue
Joined
·
8,842 Posts
Re: '81 KZ440 Installing Airbox

I've never worked on a 440, but I can't imagine that the correct method for removing/installing an airbox involves bending brackets. The 1000 and some others that I've heard of, require that the carbs be removed in order to remove/install the airbox. Are you certain that the 440 doesn't happen the same way?
 

·
Registered
Joined
·
48 Posts
Re: '81 KZ440 Installing Airbox

Glad everything is running better and better. These bikes were simple and made to do only one thing and that was to run. Emission standards were changing and most imports were just reacting to make a bike that ran. I have since picked up another KZ440 and got it running in stock condition. No mods and it runs well to 75 mph. Remember simple transportation (er fun simple transporation).
 

·
Registered
Joined
·
21 Posts
Discussion Starter · #8 ·
Re: '81 KZ440 Installing Airbox

Lucky you.
This is still not running good. Half choke to run at low-mid throttle.
Took forever to idle properly, today was 35F.

Id say all the work I did was a slight improvement from I got it. Ran only on full choke.
Ready to piece it out.
 

·
Navy Vet Search & Rescue
Joined
·
8,842 Posts
Re: '81 KZ440 Installing Airbox

If you are having to run it with the choke on for more than a couple of minutes of warm up, you still have some blockage that hasn't been cleaned out of those carbs or you have a bad air leak.
 

·
Registered
Joined
·
3 Posts
I know this forum hasn’t been talked on in quite a while but I have recently purchased an 80 kz440. It has been modified into a bobber style bike. After some work I was able to get the bike to run. But after idling for a few moments the rpms starting ramping up and had to kill it. Any time I tried to lower choke it died. With the bobber modifications the airbox will not fit on the bike. I have seen some ppl use a micuni single carb on this bike is that what is recommended or should I try to clean and tune the Stock carbs without the air box or is that never going to happen?
 

·
Registered
Joined
·
4,681 Posts
This won't be much help, but I'm pretty sure someone here posted some info about tuning the KZ440 for the individual pod filters. You'd have to do some searches. I want to say it was kawpaul, but don't quote me on that.
 

·
Registered
Joined
·
1 Posts
I know this forum hasn’t been talked on in quite a while but I have recently purchased an 80 kz440. It has been modified into a bobber style bike. After some work I was able to get the bike to run. But after idling for a few moments the rpms starting ramping up and had to kill it. Any time I tried to lower choke it died. With the bobber modifications the airbox will not fit on the bike. I have seen some ppl use a micuni single carb on this bike is that what is recommended or should I try to clean and tune the Stock carbs without the air box or is that never going to happen?
So I have myself an 82 kz440 having the same problem haha surprised anyone is still asking on this forum but I have no air box on mine and have it bobbed out as well I’m building a custom air box myself later this week to see if that helps with the back pressure since I noticed on the top end I have no tube going to an air box so I’m only assuming that not having a line to help circulate the air pressure is most likely the problem we are having
 

·
Registered
Joined
·
4,681 Posts
Unless it's plugged, the crankcase breather probably shouldn't have any effect on how it runs. The breather tube is routed to the airbox so that the fumes can be burned by the engine.
 

·
Administrator
Joined
·
3,598 Posts
Will this help?

or this
 

·
Registered
Joined
·
351 Posts
If you can not find what you looking for you may want to try this approach. Fabricate your new air box. Make the side where you plan to put the intake opening flat. leave a reasonably sized inlet opening. Cut a door larger than the opening. Slot the cover for bolts and wing nuts. Ride and progressively close door until you get to the point where it runs properly. Alternately you could use a hole saw to make a round hole. Then use a larger hole saw to make a cover disc. Swing disc for adjustment. Once proper location is obtained substitute nylock nuts for wing nuts.
 

·
Registered
Joined
·
1 Posts
I know this forum hasn’t been talked on in quite a while but I have recently purchased an 80 kz440. It has been modified into a bobber style bike. After some work I was able to get the bike to run. But after idling for a few moments the rpms starting ramping up and had to kill it. Any time I tried to lower choke it died. With the bobber modifications the airbox will not fit on the bike. I have seen some ppl use a micuni single carb on this bike is that what is recommended or should I try to clean and tune the Stock carbs without the air box or is that never going to happen?
Hey, did you ever figure out if the airbox was your issue? Just rebuilt my carbs and this is the problem I have remaining, there's a guy on ebay selling 3D printed ones for about 100 bucks but I'd hate to put it on there and find out that's not what would solve it. Thinking about fashioning my own airbox cap, since I have the stock airbox, I'm just missing the filter housing.
 

·
Registered
Joined
·
313 Posts
Fabricate one. Your just sealing a box to get the proper volume of air in there. It shouldn't be hard to do at all. It could be done with Tin and Butyl rubber. Don't pay some jerk who's trying to get his money back on his 3D printer by raping everyone. (I worked with 3d printers when they were top secret back in 1983). IMHO ;)
 
1 - 18 of 18 Posts
Top