Leaking petcock on '79 KZ400

Hi all. I'm new to the forum and new to owning a KZ, and NEWER to owning a motorcycle in general. I'm looking for some much-needed help. It appears that the fuel petcock on my 1979 KZ400 is leaking (more like GUSHING) when in the ON position. My friend was trying to help me get it up and running after purchashing it from someone on ebaymotors. After putting gas in the tank and trying to get it started, we noticed that fuel was leaking out the side. It looks like it was coming out of the side/bottom of one of the carburettors. I had read somewhere that this can be super double-plus UNGOOD since fuel can spill out and get into the crankcase and fubar the whole bike. My question is, at this point: How can I go about fixing/replacing the petcock that I have now and what do I do about the flooded (filled up) carburettor? Hunting and Googlin' the 'net didn't find me too many replacement parts for a '79 petcock. The rebuild kits I've seen either didn't mention my model or were for the '78 or '80 and I wasn't comfortable with whether it will work for the '79. Anyone that can reply or email me with sagely advise and wisdom concerning this problem, PLEASE! *smile* Your help would be greatly appreciated. Thanks

~William
w_doyle@adelphia.net

Post edited by: wdoyle1980, at: 2006/06/19 02:58

Usually I see 3 types of petcocks. Spin on used by the old kz900's and such. Then there are the plain jane (my apologies Jane). And then there are the vacume petcocke that use a vacume hose to open the petcock. This former unit has no off position just PRI for prime, ON for...well you know on!...and RES for reserve when you forget to gas up because the astronomical price of go juice. You can get rebuild kits for all types at z1enterprises.com or many other outfits like Dennis Kirk and such.

As for the carbs there is a guru here called wiredgeorge and he has a website that deals with carbs. But I must warn you the guy has addressed about every issue with carbs here about 100 times so if you peruse the archives you will find the info you need. If not you will find posts by him and in his signature you will see a link to his very usefull site. That way he gets more bench time and people get their carbs done. Carbs can be intimidating but it sounds like you have a gunk or float problem. Nothing a good cleaning can't fix and with his help it's not that hard. Luck!

WG: I don't mean to speak for you. Wack me with the rolled up paper if I stepped on ya! :blink:

How can I tell if I have a 1979 KZ400- B2 or H1. What are the differences for The engine,carbs, and tank/petcock?

I haven't had the chance to have anyone help me remove the gas tank and petcock to disassemble it. Does anyone know what the standard diameters of the gasket and diaphram are for this petcock? I found a company that has tons of rebuild kits for petcocks, but apparently not one specifically labeled for my cycle. Is this petcock usually a bolt-on or a thread-on style? Vacuum powered/assisted or manual? I'd just like to know what I should be looking for when I go and yank the tank, drain it, and look to remove the petcock. Any help would be greatly appreciated. thx.


~William

You can tell if it's a vaccumn or gravity by looking at the petcock on the bike. If all you have is one fuel line running down to the carbs then it's a gravity feed, if you have a fuel line and a vaccumn hose then you have the vaccumn style. I'm not sure about the o-ring or gasket sizes though, you're best bet is to determine which style you have and check Jeff's stock at z1enterprises.com. Good luck!