1981 KZ550A2 Update

For the record Nessism was right from the get go, now what to do? It has a rebuild kit in it. I carefully cleaned it too. Even took some emery cloth to it. Will a 650 tap fit? It is a tough fit with a rearward exit fuel line. Any suggestions.

R

R,
1st. Kudos for having the patience & logic to figure this out. I'm impressed.
You said ur petcock has a rebuild kit in it. Is it possible some dirt in the fuel has fouled the unit?
I also gotta think about the rebuild kit... possible one or more components were DOA? It wouldn't be the 1st time i've installed a brand new part only to have it be defective or ineffective.
At any rate, i'm sure you'll resolve it.
Thanks to all the gurus here too. You guys rock!

rrsmsw9999 wrote: For the record Nessism was right from the get go, now what to do? It has a rebuild kit in it. I carefully cleaned it too. Even took some emery cloth to it. Will a 650 tap fit? It is a tough fit with a rearward exit fuel line. Any suggestions.
R

The image below shows the hole spacing on the 1977 KZ650 C and B model petcock. These petcocks are manual (thank goodness!) with no diaphragm or any other gadgetry in there to go bad. Ed

Thanks, I've had bikes since I was teenager, but really liked miles more than projects for a long time. I have over 200k in the saddle. As I am getting older, kids off at college I find without some kinda project I'd go frickn nuts!!! So even when things don't go my way, I relish the learning experience. The day will come when we can't do this stuff. I also find that still most of my problems are caused by me :laugh:

R

Pretty sure the 550 is 44mm. Dang, I did clean it out. The diaphragm is fine. The oring side was varnished and rusted when I started this process. I cleaned it again and lightly buffed it. It's holding for now, but it's a short term solution. There was some pitting on that seat area when I started cleaning it three months or so ago. I may try a thicker oring, but will have to look around. The size thicker I have is not the right ID for the stem of the diaphragm. More to come. Great little bike. R

But how is the gas getting on the floor? If the petcock leaks, it still ahs to flow into and out of a carb.

Are you saying the gas was dripping external to the fuel lines?

I've had several petcocks that would dribble a little when the bike was off and the fuel line was removed from the carbs, but that never caused any gas to leak onto the floor because the float valves were working properly. A rebuild kit, and petcock cleanup always fixed the problem for me. Sometimes I put a little more wave into the circular wave spring to seal against the 4-hole seal.

Yep got it. This morning # 1 had some leaking too. Gotta be some trash in there. Thru the overflow. No external leaks anywhere. I glossed up the petcock with emery and some light buffing. It is holding now. Will keep checking it out. R

Did you use OEM Kawasaki rebuild parts for the petcock or K&L? If K&L then you might want to order up the proper parts from Kawasaki, assuming they are still available that is.

Foreign material in the petcock can foul the sealing. I'd take it apart and make sure there is no crud holding the diaphragm from sealing against the small O-ring. My 750 petcock leaked after a rebuild but the problem was traced to foreign material left over in the tank after I painted it.

K&L form z1. Not sure if kaw is available will check. The petcock was pretty fudged up from sitting a long time, some pitting. I cleaned it well last night and it is holding now, but probably short term. R

Hi there, Im new to this forum, but have recently finished my KZ550 a2, check it out on youtube ' kawasaki kz550 rebuild' .

I had the exact same problems with the fuel leaking, sometimes it did sometimes not, from different carbs, I had them on off on off you would not believe, changed all the bits as you had, no joy. What it is, is the fuel, or the ethanol in it! The ethanol first attacks the rubbers ( petcock diaphram) it makes the tiny sealing ring around the stopper go hard, which allows a tiny amount of fuel to pass, the fuel then fills the carb or carbs up because the ethanol gums up the pins in the float which it pivots on, causing the carb to overflow.

The problem with the ethanol in the fuel is it soaks up water vapour, just put some fuel in a jar and leave it open for a while watch it cloud and sometimes form little blobs of gel, this happens in your tank and in the carbs because they are vented to the outside air.

I simply got over this by putting a 1/4 inch inline METAL fuel tap under the tank, which I switch off when not using, problem solved!

One more thing if you have not done so, change the old fuel lines with new ethanol proof ones, the ethanol eats the fuel lines inside leaving gunge in the carb bolws. Hope this help.

I watched your video a while ago. Nice job. R

So I am satisfied that my petcock is trashed. It was very rusted and has some pitting that is not recoverable. I ordered a replacement that has downward exits for fuel and vacuum ports which should work well. I could not fit a rear exit manual one as the fuel line hit the air box. Even with a 90 and 180 degree elbow I couldn't make it work to my liking. Carbs are back on, waiting for the mailman. I also replace drain screw orings. The inner ones were smashed and brittle. I could have had some leaking from there too.