My KZ550 is leaking gas from carbs... Need Advice

Let me begin by saying I have never rebuilt or even open a carburettor but have always wanted to learn. Upon seeing that my 1981 KZ550 A2 with TK Carb was leaking gas from the air filter box I decided to remove the airfilter box, clean it and inspect the source of the leak. I am now face with a decision to either have a professional do it or do it myself. I do have the time to do it but would like to get advice regarding my situation from someone who is experience or has gone through it. My questions are as follows:

1. W/o the air filter box, should I run it to find out which bowl/float is defective? Is it bad to run it w/o the air filter?

2. The intake boots are hard but look like they are still functional. Is there technic to making it soft for instalation (maybe letting it sit in hot water?).

3. Is it worth just replacing the air filter with KNN Pods?

4. How much is a decent price if I have a professional mechanic do this job. From what I read here in the forums it seems like the float is stuck due to the bike sitting for 6 months.

5. Should I just buy a used carb on ebay?

Thank you in advance.

Hey jnymdnyt, welcome to the group. Here's my $0.02:

1. I think it would be ok to start the bike and run it just enough to see which carb is spitting gas. I wouldn't do it too long, 'cause it'll be running really lean.

2. Soaking them in hot water is about the only way I've found to soften them up. Once you pull them out of the water you've got about 2 minutes to get them on before they stiffen up. I used to have the camp burner out in the garage with me. Finally broke down and bought new boots....heaven!

3. I'm a bad person to ask 'cause I like to keep everything stock, but if you switch to pods, you're going to have to rejet your carbs too.

4. I've cleaned up carbs on all my bikes, just take it slow and keep track of all the parts. Sometimes you need to buy some "carb kits" to replace jets, float needles, and o-rings. Other times a good cleaning is all it takes with carb cleaner and compressed air. I do have my mechanic balance the carbs and that runs me around $70.

5. I'd recommend buying a manual on ebay and try to re-build them yourself.

Good luck!

sounds like your float valves are not sealing some times if they are not to bad you can polish them up with some thing like brasso but usally that is only temporary so replacement is usally the answer also the intake boots can be softened up with a heat gun or hairdryer if you have one i have always found that to work the best. a mechanic could charge up to 3 hours or more labour for this job if the carbs are a real mess. depending on the shop and what they have to do to get them to workproperly.

As a fellow KZ550 owner, I would be happy to offer a few words. First of all, the TK carburetors on your bike are very easy to work on. You may want to replace all four float valves. Be sure to check each float to see if it ok (still floats). You would be happy replacing all of your rubber intake boots as they can be a source of headache. Ebay or Z1 enterprises is the place to find all of this stuff. You may want to take your carburetors apart before ordering any parts. My bike was doing the same thing as yours and I just ordered four float valves off Ebay and everything is fine now. Recommend keeping the stock airbox and replacing the air filter, unless it is new. If you take your carburetor apart before ordering parts, you might find that you need some jets, gaskets and o-rings in which case you can order the K&L carburetor repair kit from Z1 or Ebay, which includes the float valves. It is all very easy to do yourself and you will save a bundle of money too!

Robert

Thank you link14, timebomb33 and Robert for all your advice. All your answers are spot on and gave me the confidence to go in and learn something new. I'm also a fan of keeping it original, I just thought it would be easier to replace it with pods.

Another thing I noticed that might be important to note, when I took the gas tank out, I couldn't stop the gas from flowing out. I know this is such a newbee question but where is off. It's surely not on or reserve but prime does not seem to help either. Could the petcock be broken as well and is part of the problem? Where should it be when I'm not using the bike overnight?

Hey bud im working on a 550 a2 thats had the same problem. Sounds like the petcock is fried. Its vacuum operated, so no gas should come out unless its set to prime. Id replace that first, see if it still leaks. Those carbs are easy to work on, keep in mind youll probably need fresh float bowl and upper carb gaskets. Now, the pilot air screw, or air screw is located behind a plug on each carb. When i rebuilt mine i didnt get the plugs out and change that jet, but it seems i really should have. So you do yours! Also, the carb kit I got seemed to come with different size needle valves. The needle valves are what controls your fuel levels/ floats and youll want to set them before you go trying to start it. If those plugs intimidate you, do the rest of the carbs and then bring it to the dealer and just get them to remove the plugs. Good luck..

Looks like I found out the culprit, it's not the petcock because I tried putting it in reserve and on position and gas did not leak (thanks to violentvintagerider's advice) so it still works. I ran the engine w/o the air filter box and a few minutes after I turned it off gas slowly poured from the first chamber of the carb on the left side.

Now I'm going in to check/clean or replace the float valves on just that side to get a better understanding and if I feel confident enough maybe I'll do the rest.

What's the best carb cleaner out there?

Thanks again.

Would suggest that you just replace all four float valves. When you take the float bowls off your carburetors, see if the seat portion of the the float valve is loose. On my TK22's, they were all loose (could loosen by hand) and I probably could have just tightened them up and that might have stopped my fuel leak. Apperently, the composite gasket had shrunk over the years, causing things to loosen up. The new aftermarket seats have a steel gasket, or at least some of them do. I just use the cheapest carb spray I can find, so no great advice there.

Robert

I got a diagram of the TK carb parts along with part numbers to help me identify all the parts. I'll be more than happy to post it if anyone else needs it.

I opened the float bowls and checked if the float valves are loose, it wasn't. How will I identify which part is causing the leak? Do I have to just clean it or get a carb kit and replace everything? Is it just me or does this carb look like it's been worked on by the previous owner? Please see attached picture.

Sorry, did not see your post and picture. I would replace the float valves and try it, since it looks so clean. You can find them separately for approximately half the price of a kit. If it had been dirty and the gaskets were torn, then the kit would have been my choice.

Robert

Buy new boots from z1 ent. I did this a week ago, and made the installation of my rebuilt carbs a breeze. I never attempted a job like this before, and the support from this forum got me through the process. If you don't wish to rebuild the carbs yourself, there are plenty of decent carb rebuilders out there who can do that part for you.

My 2 cents

I have 82 550GPZ H1 with TK carbs. when i purchased it it was not running correctly. noticed that the part number 92063-1122 A noted as secondary not primary jets were broken tabs. who carries these. what is the stock size? also can i use another type like mikuni, etc.

see pic of one good one...