kz440 idle problems, won't run very far

I got a full tune up this winter and have been ridding my bike a little bit at a time. I finally took it for about an hour long ride the other day and it ran decent. A few hours later I went to go pick up my old lady about two miles away and the motorcycle went crazy on the way home.

It started out by not getting much power at all from the throttle while accelerating, almost stalling out most of the time before getting out of first gear and would make odd 'pipping/putting' noises before finally staling out and letting out a pop from the exhaust. It wouldn't start back up, so I was forced to leave the bike on a side street and take a cab home. Today, two days later, I walked to the bike and started it up fairly normally and rode it home, almost all the way. I rode about a mile before it stalled out again while making the same pipping noise. Needless to say I walked it the rest of the way home.

I pulled out the air filter and it looked fairly clean, but the end that fits to the carburetor looks almost like some sort of corroded material... Is it supposed to be spongy like a gasket of some sort? Looks worn away. The gas in the tank is new and there is oil in it. I did notice though that one spark plug has a bit of carbon on it. I planned on putting new oil in it today and putting in new spark plugs but the parts store was closed.

Other than that the bike was running fine before. When I took the hour ride it ran hot, but that's because there was a lot of stop go traffic (I live in Brooklyn). The idle has always been a bit erratic, but I know these bikes are cold blooded, but most of the time I have to leave the throttle a bit open otherwise it idles too low and stalls out.

Any suggestions as to what this may be? I'm hoping the carburetor isn't clogged or something, I've never worked on a carb, but i guess there is a first time for everything. Any help is appreciated! This is my first bike

AnxiousCowboy wrote:

...I pulled out the air filter and it looked fairly clean, but the end that fits to the carburetor looks almost like some sort of corroded material... Is it supposed to be spongy like a gasket of some sort? Looks worn away. The gas in the tank is new and there is oil in it. ...

Does the bike have the stock airbox or pod filters?

Doing carburetors isn't really hard... especially when there's only one or two.

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No, my bad. There is oil in the motorcycle. My first thought when the engine died was that the oil leaked out. Everything is stock, I heard these things will work with nothing else. Here is a pick of the filter on it now, Should I add a new one on the list of things to purchase? Doesn't look very new which pisses me off since this thing was supposed have had a full tune up this winter.

Any ideas what could be wrong? are these symptoms of a clog in the carb? I have a manual and tool--just need to be pointed in the right direction.....

If not already done, would assure correct valve clearances.

Good Fortune!

Changed the oil and filter out and put in new spark plugs and adjusted the idle. I rode it on and off around the block a few times and so far so good. Little scared to take it too far cus I don't want to have to push it home.

Where can I find stock air filters for this thing!? pep boys only had them for KZ750s and I'm not seeing any online....

Z1Enterprises.com would be the most likely place. They specialize in vintage bikes & are located in Upstate NY somewhere. They advertise here on KZR. I've made several purchases from them: they're very helpful, the prices are reasonable & often times better than others, and the shipping is usually fast.

Unfortunately z1 only has the aftermarket pods... the filter itself is in good condition, maybe ill just glue some sort of weatherstripping to the erroded part in the pic to keep a good seal. Will I have to worry about it melting? What material should I use?

The diagrams at Kawasaki.com for the 1980 KZ440-Ltd show that the filter element is listed as Active, so Z1Ent should be able to get it - 11013-1027. You should verify the part number.
Or search the part # on ebbaayy - there's one listed - $8.99 +shipping.
RonAyers.com shows a price of $5.56 + shipping.

Note: The KZ440s have several different airbox setups. You ought to check the diagrams to verify what you're holding. It looks to me like that's the case & cap or something, and you'll probably have to scrape off the old foam & come up w a way to seal it.... and the actual filter element is kinda inside.