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Leaky Petcock - wrong diaphragm for KZ650

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16 Jun 2022 07:47 #868898 by mjjund
Hello, on my '78 KZ650 the petcock started leaking so i ordered a rebuild kit for it and once taking it apart the diaphragm part that was original to the bike does not match what came in the rebuild kit. I have checked rebuild kits at a few different sites and they all have the same replacement diaphragm but it does not match and i can't get the new part to fit. Does anyone have any insight into this? I have attached some pictures, the first pic is the new replacement diaphragm and the last 3 are the original part and i can't find anything like this.
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16 Jun 2022 08:57 #868902 by Mikaw
Replied by Mikaw on topic Leaky Petcock - wrong diaphragm for KZ650
This? maybe? Looks like it might be an updated version.

www.partzilla.com/product/kawasaki/43028...6b5575de4884fc22fabd

 

1976 KZ 900 A4 kzrider.com/forum/11-projects/613548-1976-kz-900-a4
1976 KZ 900 B1 LTD
1978 KZ 1000 B2 LTD
1980 KZ 750 E1
Kowledge Speaks, But Wisdom Listens.
Jimi Hendrix.

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  • gd4now
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  • Denco where did you go?
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16 Jun 2022 09:30 - 16 Jun 2022 10:23 #868905 by gd4now
Replied by gd4now on topic Leaky Petcock - wrong diaphragm for KZ650
In  the past there was a long topic on the kz650.info site about this topic.  Here are the part numbers I could find for the vacuum petcocks that came stock on the 650s from the earliest to the latest.

51023-1005
51023-1011
51023-1013
51023-1023
51023-1370
To the best of my knowledge the first one listed does not have the "top hat" looking part. I have attached parts list for it (1005)

I ;have also attached some pics showing the difference between the petcocks without and making use of the top hat item.
It would appear that the kit with the hat has been NLA since like 1999.

1977 KZ650 B1
Pods and Denco header


OLD KAW OWNERS SMILE ALOT

Last edit: 16 Jun 2022 10:23 by gd4now.

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17 Jun 2022 16:52 #868997 by rstnick
Replied by rstnick on topic Leaky Petcock - wrong diaphragm for KZ650
Lots of people have tried and failed to rebuild these fuel valves.
I ended up replacing mine with a Suzuki fuel valve with 44mm spacing.

Petcock - Vacuum - 44mm - Suzuki | Kawasaki and Suzuki Motorcycle Parts | Z1 Enterprises

Rob
CANADA

Need a key for your Kawasaki? PM me

1978 KZ650 C2, 130K kms, Delkevic ex, EI, CVK32, PMC easy clutch, ATK fork brace, steering damper, braced swingarm, ZRX shocks, 18" Z1R front wheel.
2000 ZRX1100
2011 Ninja 250R - Wife's
2005 z750s (aka GPz750)
1978 KZ1000 project
The following user(s) said Thank You: Nessism, Mikaw

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17 Jun 2022 18:40 #869000 by xstreamcanadian
Replied by xstreamcanadian on topic Leaky Petcock - wrong diaphragm for KZ650
I had the same issue on my 78 SR, I changed the tank out to an older tank from a 650B as I like that tank style a lot better. Rebuilt the petcock, it wasnt leaking  but the vacuum on/off wasnt reliable, it was either not working or going crazy full flow. I gave up and went with the adapter plate that allows for a 3/8" NPT petcock. This looks ok, but also a giant PITA as the one I got from Z1 sucks. It leaks also, from the petcock switch for lack of a better term. I ended up making my own gasket for it, and that seems to have worked, the thing i discovered is that the 3/8 is very common on old harleys so you can source those anywhere. I may spring for a pingle. They dont leak. Also I used motoseal on the bolt threads and the petcock thread. Seems like no matter what way you go, you have to really pay attention to the details and seal the holy hell out of it sadly. the old one previously didnt leak, with no sealant and only the factory o ring, and that would be my preferred method. 

good luck man

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