TOPIC:

Hi everyone, I am new to motorcycles, just bought a 1987 Kawasaki KZ305 LTD belt drive bike because I wanted to learn this summer, and thought it looked super cool. When I bought it, it would start but would not idle. So, naturally I cleaned out the carburetor and reset the jets. Now, it starts and idles, but at 3000 RPM, which is not good. I am getting very confused because diagrams in the service manual I have are not accurate to what I am seeing on my bike. I am having trouble with the idle adjustment screw.
Here is my Left Carb




Here is my Right Carb



I see nowhere on the side here to adjust the idle, only the vacuum plug screw. However, my service manual has this picture.



That screw is not on my bike. However there is also a hand turning screw that is labeled as an idle adjustment screw. My bike does have this screw which is pressing down a spring, however it appears to be stripped or damaged. It is screwed down pretty tight and there is no knob to unscrew it. I should have taken a picture of it when I took off the carb, but i didn't. I will though next time. It is directly between the two carbs. Here it is in the manual.




And in relation to the other carb parts.




Ok, so I know you must be thinking, well, obviously I should replace the idle adjustment knob screw that I hightlighted in the pictures. But, I can't find it anywhere on any part shops. All of their diagrams for my model bike don't have that knob screw on them. Here is a link for reference.
www.partzilla.com/parts/search/Kawasaki/...28U.S.%29/parts.html

So that is my main confusion, if anyone has any insight as to what I should do, it would be greatly appreciated. I am getting frustrated with the inconsistency. On a side note, so you might get a better understanding as well, at the moment I do not have an air filter on the bike,and I know this could be affecting my idle, but I can't imagine not having an air filter would cause the bike to shoot up to 3000 RPM. I did find a replacement filter, but just realized I am missing the "air filter cap"
It looks like this, if anyone knows where I could find one, that also, would be of great help.




Any help would be amazing! Thanks!
-Benzi-

Hi, I am not familiar with your bike at all, however first thing is make sure you have the right owners manual for your bike, go tp Kawasaki.com and click on owners centre, next click on parts, scroll down and click motorcycles in category, next click 1987 in select year, next click LTD in select vehicle and next click continue to get a full parts diagram of your bike.. Here is a direct link to your carburetors www.kawasaki.com/Parts/PartsDiagram/26418/1987/KZ305-B2. Whenever your carburetors are revving to high its an indication that you may have a vacuum leak, check carb holders for small cracks by spraying carb cleaners to carb boots,while you have engine running if your idle changes you might have to tighten the clamps a bit more, or you need to replace the carburetor boots, hope this is of some help.

Hi and welcome to the forum.

I dont know much about the 305 but here's a few thoughts until the experts get here

If your idle screw (#9 in the first diagram) is buggered and no longer available then the good news is that it is a metric bolt and something suitable should br easy to find in any hardware store selling metric bolts. You'll have to disconnect gas lines, remove gas tank, remove throttle cable and take out the carbs to get at it. Not as bad ad it sounds. Once you find a bolt the right size you can make a knob with a bit of epoxy putty or JB Weld.
If the threads that the bolt goes into are buggered then new threads can be cut.
All very fixable.

A missing air filter can indeed cause the motor to idle high. I notice in your second picture above that the airbox hose is not a good fit to the right catb and does not have a roll spring or clamp. Even a small air leak here could cause a high idle.

Sorry i cant help with the missing airbox part (ebay?) but thrre are a few 305 owners here who may may have suggestions

Yeah, I was planning on getting clamps and tightening it up when I got the airbox situation all sorted out, but I never thought that an air leak like that could cause high rpm. I will definitly try tightening everything up next. Thanks.

So, first off thanks for the replies, I have taken into account all the feedback. I found an airfilter and box on ebay luckily, although I paid a little more than I would have liked. Oh well. Installed that, along with some hose clamps for the carb air intakes and fired her up. Usually the bike will immediately shoot up to 3000 RPM, however, with the proper air intake, it appears to idle properly for about 20 seconds, before going up to around 2600 RPM... which is an improvement, but not ideal.

At the moment, I have a carb off the bike, and I managed to get the idle adjustment screw off, about to go look for a replacement, or possibly just make a puddy handle on it with the JB weld. BUT, my big question for you guys, is while i was tinkering I noticed something that looks off. The idle cam and the idle link. They look like they are suppose to line up... but they don't. Could you take a look at these photos and share your thoughts?







I'm pretty sure that the link should be resting on the cam, But, is the link also suppose to be in the slot that houses the throttle cable? Is is supose to move when I throttle to adjust the choke automatically?

Hi Benzi, I have an 82 305 with the same carbs. Yes that idle link is supposed to sit on the cam. When you have the choke fully on it pushes the throttle a little bit from memory. I have my carbs off the bike so l can take some photos for you in the morning. Also I think the diagram you are looking at in the manual is for the kz250 carbs, you need to find the kz305 supplement pages towards the back. Good work finding that airbox. I sold my old one to another member a few months back.

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not sure if you can see it clearly but the fast idle link is resting on the cam, and it does open the throttle when using the choke. Note the idle adjuster on my carbs is flexible and bends to one side for easy access.

Amazing to see what it is suppose to look like! Makes more sense. At the moment I just have a metric screw in it and I adjust with a tiny phillips head, which is a pain. Any idea where I could order one of those idle adjustment cables? Also, I bent the link back over, so that it is on the cam. With the idle adjustment screw all the way down, I can get it to idle decently, with the choke out about half way. When I close the choke the bike revs up super fast, over 3000 RPM and then goes down to like 1000, then back up to 3000 in about 3 second intervals. My friend thinks there is an air leak somewhere. Any thoughts?

Good chance it is an air leak. Are the intake manifolds new or nearly new? If you can see surface cracks, they are likely shot. Are the carbs fully seated in them? Good spring clamps installed? Are you sure there are no leaks between the carbs and intake boots, or the boots and the box?

Have you checked the ignition advancer? If it is not moving freely, or if the springs are all flippy floppy, (technical term for worn out) your ignition timing may be all over the place.

My timing advancer was worn. It made a big difference when I replaced it. It started way easier and settled to a nice idle. I also have new carb intake boots on the way.

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