Won't start without a bung

OK i put a new stock air filter on my 82 KZ750-e3 last week

now it won't start without a t-shirt or rag jammed in the top of the air filter

any thoughts ???

thanks

sounds like a vacume leak, like a hose is off

I just put my hand over it to see if it was sucking in air to start. then jammed a rag in it (I ain't ridin' it like that, don't panic)

there is a hose going to the crank vent. another going to the vac system. And another two smaller holes in the bottom of the air box. anyone know if these two should have hoses coming from them ??

you should work at a steelership with those diagnosic abilities:devil:

:roflmao::roflmao: :roflmao: :roflmao: Good one Skull

If memory serves, there originally should have been an air box with a filter in it and a cover on top that either screws or snaps into place. All those components need to be in place for it to run properly. The two holes in the bottom are to let water out I think so there may be no hoses to them. Don't quote me on that but I am fairly sure there are no hoses coming from the bottom other than to maybe redirect any water to the ground. You could temporarily plug them just to get it out of your head but I really don't think they are your issue. The air box also needs to be securely mounted to the carbs as well.

Was this something that was previously running and now is not? Or is this the way you got it and you are trying to make it run? A little history would be helpful.

Those old ricers need a little TLC if they've been sitting. Check the rubber boots/seals on the intake as well. If they are sucking air it won't run right either. They are very prone to dry rot.

Basicly then you have to choke it to get it to run. It's not getting enough gas. Could be the pick up tube in the bowel is gummed up. Or it could be the Vaccuum petcock. I don't remeber if those had one that year or not.

Once it starts with it choked will it stay running when you unchoke it??

it needs choke to start
I thinks i'll rip the carbs off and give them a clean.
when i turn off the choke it dies on me.

this is all still with a rag jammed in the top of the filter

hmmmm.....

Hey triggerbilly, I wasn't laughing at you,I found skulls comment pretty funny tho. Is the bike an inline 4? I've had Kawi's before but it was a '76 and was just called KZ900.What's the e-3? If its an inline 4 with a bank of 4 carbs don't take them apart, leave the carbs together as an assembly.If the bike was sitting for a while the carbs will need a cleaning. A couple of years ago my bud and I fixed up an '84Kawi 550 LTD for a girl and it had a vacuum operated petcock. If yours does check that out too. With hers all we did was clean up the carbs and I think we changed the petcock to a gravity feed one, just remember to turn off the gas when you get off the bike. Make sure all your fittings from the airbox (should be a cover on it) to carbs to intake are all in good shape and are all seated right.

That is sort of the direction I was heading too Lucifer. That's why I wanted to get a bit of history as to what was going on. I have also done a bit of work on some vintage Japanese bikes. Mostly Suzuki but a little on Kawis too.

I still do the maintenance on my buddies 79 GS1000. The bike is bone stock and simply will not run with the air box disconnected or even without the cover on the top. Runs fine all buttoned up though. If the only thing missing on the air box is the cover that you are putting the rag in, then try putting a little piece of cardboard or plywood over it for testing purposes. If it runs fine like that then you need a cover. If not then there may be several issues including all of the above.

His had a petcock issue too but it just leaked because of a crack. I made a gasket for it and bought a diaphragm to get him down the road and ordered a new stock petcock because he wanted to keep it original. It was around $65 a couple of years ago.

Once it stays running, spray WD40 (or similar) on the intake seal(s) going into the carbs and the rubber intake boots going to the motor. If it has been sitting, there is a very good chance they leak and need to be replaced. I'm not sure which type yours has. Some are all rubber and can be a little pricey. Some are metal with rubber O-Rings on either end and are pretty cheap.

Again a little history would be helpful. With the crappy gas we have now and the age of the bike and if it has been sitting for more than a few months, it is almost a certainty the the carbs need a good cleaning. Be careful not to loose anything.

OH YEAH, if yours has the little Philip head screws holding the intake boots on, have an impact driver handy to get them out without destroying them and replace them with a Torx or Allen head screw. The heads get rusty and soft and the threads get oxidized in the aluminum.

Sure sounds like the needle jets to me.

thanks guys

the bike didn't run for 20 years, It is a 4 cylinder with a bank of 4 carbs.
the guy i bought it from said he cleaned the carbs (don't know how well)
As soon as i put the carbs on, I got it running, then the trouble started ( so i'm thinking it might well be some dirty fuel from the tank (which serves me right as i didn't clean it out) and i only just put a fuel filter on the hose.

should i try and have a look at the (Vaccuum) petcock before i rip the carbs apart or should i do both ??

here's a pic

A guy came up last year with a Yammahaha XS1100 that he said he rode it in the barn and parked it in 1982 and took it out in 2007 and asked if we could get it running for him. The stench of stale gas was unbelieveable. you couldn't move the vacuum pistons in the carbs with a sledgehammer. It took a month sitting in carb cleaner just to free them a little. I've never seen anything like it.
I think you should take off the tank and flush it a few times to get all the crud out,take out the petcock(if its vaccuum type ,they're be a diaphram behind the shutoff,gravity feed doesn't)and give it all a real good cleaning. If the carbs are CV type make sure the slides move up and down freely.Leave the 4 carbs together as one unit, take float bowls off and top covers to inspect diaphrams for tears or holes, be very careful with them so you don't pinch or tear them.
Carefully check all the intake fittings for cracks,esp carb to engine ones. They could have dry rot.Air leaks there and it won't run worth a sheit if at all.
A real good cleaning and fresh plugs and it should fire up and run for you.

Good luck!!:devil:

Since it's been sitting so long, I would also replace the fuel lines. Even if they don't look bad on the outside they could be gummed up on the inside. And if it has been sitting for 20 years and there was still fuel in it then you sucked that bad gas right through the cleaned carbs. Check for rust in the tank too when you clean it. I helped a guy clean and coat a couple of tanks with that POR15 tank kit stuff. It seemed to work really well although it takes a lot of time to do it right. Don't do like we did. Start in the morning. That way you won't be up drinking until 2:00 AM waiting 20 minutes between every single step.

Looks like a pretty good find. Good luck with it and have fun.

ok i flushed the tank out,
took the carbs out and cleaned them
(the guy i bought it from had cleaned them)
I recleaned them and my main job was getting the throttle slides
clean, they were caked with old fuel
I've gotta go get some gas tomorrow and try it
could this have been my problem that the slides/vacuum pistons????
wern't slidin'.

just started it up, and........
pretty much the same problem !!!
well at least my carbs are cleaner !!

I guess it started a little easier but still pretty much the same prob.
it runs with a rag jammed in the top of the air filter top ????
pull it out slightly while the engine is running and the bike begins to die,
stuff it back in and it comes back to life.


after 5 mins idle around 2000rpm (won't rev without cutting out)
cylinder 1 - hot
cylinder 2 - warm
cylinder 3 - RED HOT !!
cylinder 4 - hot

tried the wd40 intake tip and no change in rpm's
It feels like a vacuum problem (right or wrong ?)
but can't think of anything else to try.
hope my findings help someone to HELP ME !!!!!!

thanks

Seems like 1&4 are working OK, #2 could be weak spark or too rich and #3 seems it could be too lean. What type of carbs are they?? CV style(piston and diaphram) or slide,Is everything(piston/slide) moving freely in the carbs. Did you put new plug wires and fuel lines in? After so long sitting it wouldn't hurt to put new wires on and I'd suggest new fuel and vacuum lines.
Gotta love those inline 4's eh.:gah:

yeah lucifer they are piston and diaphram.
I changed the fuel lines
the vac lines seem ok too
i'm getting strong sparks (should i still change the wires)

It could be a rich and lean setting
the air/fuel mix screw were plugged on these carbs for some reason ??
are there any other ways of changing the mix without digging those plugs out

thanks

If your getting a sharp blue spark and there are no cracks or sign's of insulation dried out, the wires should be good to go then. I think its just about time for some outside help. The carbs could be out of sync.and there is a "tool" bike shops used to have for syncronizing the carbs(excuse spelling ) it looks like a IV setup with 4 guages 1 for each carb. I'll tell my buddy about your symptoms and see if he can remember what the sync tool is called(could be called sync tool ) or any suggestions on whats wrong and how to fix it.
These inline 4's can be a real PIA when not right and a lot of times its fuel related. I joke with him a lot when guys come up wanting their old ricers running and tell him the best fix for the carbs is a 20lb sledge hammer and 2 swings, but he hasn't done it, YET:roflmao: .
Call around a few shops and ask if they can sync carbs and I'll get back to you with a pro's ideas on whats wrong and hopefully a cure.