Petcock help

Lets start from the beginning......... I've had a air leak for a long time with my 1979 kz400B motor head. Finally it got fixed but after getting it fixed I noticed my kz running on one cyclinder. I took it back to the shop, they took out the spark plug and noticed it was drenched in fuel. That was 2 weeks ago, I called today for an update and the mechanic told me that my petcock bypass is all screwed up and not working properly. The bike is still letting fuel into the carbs after being shut off and causing the cyclinder to get flooded with fuel and soaking the spark plug. He told me I need to find a new cockpit and hope it works.
or find a completely new tank and change the whole cockpit set up with the new tank.
What are your thoughts?

I found this link for a cockpit
www.amazon.com/Valve-Petcock-KAWASAKI-KZ...rcycle/dp/B00B4XDO8M

If I do need a new tank, what are some tanks that will fit on the 79 kz400 b2 Frame and etc.

umm I think the floats in the carbs are supposed to prevent that. I leave my petcock on prime / completely open 24/7 . if it's flooding the engine I would be suspect that the floats are not sealing off the fuel flow when the fuel reaches the proper level in the bowl. maybe fuel is leaking into the vacume line from the petcock? I would replace the petcock with one similar to the one you showed or rebuild the one you have with a kit from www.z1enterprises.com

It's petcock. Check the oil for fuel in it. Sounds like this guy doesn't know what he is doing.
Steve

Yea he did mention my oil has fuel in it.

those cheap petcocks work well. after thinking about it a bit it's probably just leaking into your vacume line bypassing the bowl entirely then going strait into the engine. is the cylinder that's flooding have a vacume line attached to its carb? you could just disconnect the vacume line plug it on both sides then run the bike on prime as temp solution. I'm very surprised your mechanic couldn't find the part. they are super easy to rebuild or replace. I would be a little worried about the work they are doing if they couldn't easily fix it. to be honest it really sounds like he doesn't know what he is doing. it's a common problem with your average motorcycle mechanics from my experience.

The four-hole packing for a KZ400 is no longer available. I used one from an early CB750. So far it has worked well.

Make sure the vacuum line isn't the source of the extra fuel. Disconnect it from the carb and see is there is any fuel coming through it - there should be none. If fuel has been flowing through the vacuum line that would explain the wet cylinder and the petcock must be replaced or rebuilt to fix that problem. If the vacuum line is dry, as it should be, then you have a problem in the carbs as well as the petcock. The floats in the carbs should shut off the flow of fuel when the carb bowls are full. If they are not shutting off the fuel flow there is either a dirty carb float valve or the float level is set too high. Ed

I'll check in with my mechanic and tell him everything you all have shared. I'm also looking at the Z1 website, what's all this diaphragm stuff I see? Do I also need to buy this along with the new petcock? And what about the 3 hole gasket?
Or should I just replace the petcock?
Sorry for all the amatuer questions, I'm not mechanically sane at all.
Just want the kz to work

650ed wrote: The floats in the carbs should shut off the flow of fuel when the carb bowls are full. If they are not shutting off the fuel flow there is either a dirty carb float valve or the float level is set too high. Ed

that was my initial though as well, but even when I had a couple grams of rust in the bowl of my carbs the overflow tube would cause the carbs to leak all over the ground before it would leak into the engine. I feal like the carbs would have to be super dirty to plug the overflow as well . who knows though, stranger things have happened
I would just put that $10 petcock on and eliminate it as a problem. I have one on my 305 and it's worked excelent for the last year. if your still leaking fuel into the engine then you know it's not the petcock.

Finally got my kz back today. Mechanic said everything has been resolved, but I noticed one thing while I rode away and I was too far and too lazy to turn around. At exactly 3k to 4K the bike feels sluggish and once it passes 4K it releases the power. But it doesn't do it while I shift at high rpms. Maybe because I'm passing that mark after the shifts. What can it be? I'm just happy I finally got it back and didn't want to turn around.
Pulling out from a complete stop its great but once it gets to 3k to 4K it's sluggish. During that mark, bike sounds different then sounds good after I pass that mark.

Other than this the bike runs great

What did they do?
Steve