1979 KZ650C idle problem

Hello my name is Keith, and this is my first posting.

Ok Saturday after noon I bought a bike off of craigslist and it was only 500 bucks. This is the first bike I have ever owned. (I am 18) I have never driven a motorcycle before but have ridden many. Ok Saturday afternoon my roommate who owns a 2000 Kawasaki W600 took it out and put a few miles on it. He brought it home and said it was fine. I tried starting it later that day and couldn’t get it. My roommate today (Sunday) told me to drain the gas tank and put fresh gas in. I did that and added engine cleaner. Now today we could get it 2 start for only a little bit. I would idle but the second we would get it past 2000 Rpm it would die out. It also would die out the second we would give it throttle for the first 10 minutess. I have been reading up and there is a little space between the airbox and the carburetors. I think there is a leak in the air box. Do you think that could be the problem? I will add pictures of the hole later.
Thanks for all your help Keith.

Welcome aboard Keith; you're going to love the KZ650C once you get it running right. Please show us the pics, but it sounds like you may already have found the problem (or part of it). Assuming the bike is stock, there should be 4 rubber inlet ducts that connect the back of the carbs to the airbox. With the seat open, you should see a round collar on top of the airbox that holds the air filter in place, make sure it and the filter are there and get a set of the ducts (you'll also need the 4 springs that hold the duct on the carbs.) It sounds like the back of your carbs are open to the outside air. This would make the bike run lean (not good, too hot) and permit dirt, bugs, and other junk to be sucked into the carbs - also not good. I wouldn't ride it until this is corrected. Here's a pic of the way the stock setup looks. Good luck, Ed

[img size=150][/img]

Yeah I have bad news. It did not fix the problem. It seems to idle for about 25 seconds to about 2 or 3 minutes then the bike dies out. I closed the holes up (used tape) just for a quick temp fix to see if it would work and it didn’t. Now if I just turn the throttle a little more than 1500 rpm it just stalls. Any help would be i greatfull

Welcome Keith.

Tape is a useful short term solution.

The basics... is there an inline filter.

If not, rust and debris could be getting into your carb and plugging different jets and or passage ways. Add an inline filter.

If yes change for a new filter.

In either case, you may need to remove and clean out the carb.

Best of success.

How would i go about cleaning the carbs. i am very new to motorcycles? i woudl ask my friend it assist me (works on cars and said he knows how 2 nut i jsut wanna know also). Is it very complicated?

woudl this be a good replacement ?
www.oldbikebarn.com/Street/1979-Kawasaki...aki-KZ650-Air-Filter
or

www.oldbikebarn.com/Street/1979-Kawasaki...c38Le34Pa38Ta38Oa3f0

on the second one it says i would need a pod per carb. Second the bike came with a air filter similar 2 the first 1. (sorry about my in experience i have a class Friday Saturday and Sunday about them I know i need 2 be more informed about the motorcycles.

Welcome!

These are wonderful bikes! Trouble is that they get problems, solvable problems, and people let them go. Their losses.

If you get four pod filters, then you will need to change the jets (ports that allow fuel in to the carb throats) as well. It might not be a bad idea to fix one problem at a time. Figure out why the bike is not running before you change something that will inevitably require more changes.... Don't get new air filters just yet. The pods are a lot of people's favorite, but you got other fish to fry right now.

Bikes of this age are plagued by fuel contamination problems. Particularly when we get in there and try to clean them out. We mean well, but we usually just stir things up and end up dumping sediment into the carbs.

My recommendation is to purge it from top to bottom. Have you looked at the inside of the gas tank? Old fuel will create a get-like film that will eventually flake off and cause problems. There might be rust as well. Is there a fuel filter?

Your question about the carbs. They are not very complicated. The trick is to get the carb bodies truly clean. There are a lot of small ports that need to be cleaned out which is more important than getting the outside clean. It might not be a bad idea to get a shop to clean out the carb bodies for you if you don't have access to any compressed air or soaking buckets. That way when you put them back together again, they will be well cleaned. This will also add to your knowledge of your bike.

There is a user here on-site named wiredgeorge who can rebuild carbs for you, very trustable and knowledgeable. Unless you would like to do it your self.

Set up a space where there will be no cats or little sisters or Mom's cleaning up. Light, space, shop rags and paper towels, parts holders (egg cartons), tubs to soak parts in, tools, cans of carb cleaner, ventilation, camera, time, and four rebuild kits. Then take the suckers apart, taking pictures of what you are doing for reference. Spend the time to be sure the things are cleaned out well.

You will have to fight them to get the float bowl levels correct. you will run into some problems that will befuddle you a bit. You will probably need some advice. But if I can do it, so can you.

As an aside, get a manual. They are indispensable. (Clymer).


Best of luck man, old school, it is worth all the work.

Post pics.

I FIXED IT!!!!!! I AM SO HAPPY!!! it turned out that their is a rubber tube from the choke and on the other side of it that was torn. like a little gash. i taped it up and then she purred like a kitten! i am so happy. A quick question how would i go about changing the rubber tubbing on my motorcycle (updating them).

A rubber tube from the choke? You may be mistaken, do you mean the petcock? That would probably be the vacuum tube that opens the petcock letting the fuel flow. If it had a small tear then I can see it not opening the petcock diaphragm all the way. It probably tore when you drained the old gas out, especially if you pulled off the fuel tank.

You can pull off the tubing and head to an auto store to match it up.