We have two early black petcocks on the shelf that both leak. The rubber sleeves that serve as seals on the rotary valve need to be replaced. They've been rumors over the years that some third party replacements were made, but we've never been able to track any down.
Mama Kaw modified the black petcocks with an O-ring on the rotary valve during production. There's a service bulletin on it but can't look it up right now. The rebuild kits we've seen for the black petcocks include it, but never the needed sleeve. It seems to be made of unobtaniium.
Our late '73 manufacure '74 Z1-A that slmjim bought new came with a late black petcock; it's one of the leakers on the shelf. When it began leaking many yeats later it was replaced with a later KZ900(?) or early KZ1000(?) dual output petcock that has the nylon cone valve. We've never seen one of those leak.
slmjim & Z1BEBE
A biker looks at your engine and chrome.
A Rider looks at your odometer and tags.
When it began leaking many yeats later it was replaced with a later KZ900(?) or early KZ1000(?) dual output petcock that has the nylon cone valve. We've never seen one of those leak.
slmjim & Z1BEBE
I have one of those on the bench right now, bought a rebuild kit for it and while it doesn't leak externally it doesn't shut off completely and fills the carbs. That tells me it's leaking past the nylon cone.
This petcock came from a 74 Z1A with a vin# of Z1F- 20024 our friend Wheelhop bought the frame last year.
The petcock on my Z1A, which has a build date of March 1974, had the natural finish and also the leaky black inner sleeve. I just replaced it with a Tiawan manufactured petcock from Z1 Enterprises, so far so good.
GLWTS, by the way!
Former M.E. at Kawasaki Motors Manufacturing, Lincoln, NE
1966 W1 (the Z1 of 1966-50H.P. and 100mph!)
1974 Z1A (disassembled)
1976 KZ900B LTD (SOLD!) it's in GOOD Hands!
1978 KZ1000 LTD
1976 KZ900B pile O parts
1980 Honda XL250S (I know, wrong flavor!)
My late 74 Z1A petcock has the nylon cone, natural finish, and outlets 90 deg apart. Just cleaned it, "lapped" the cone with a little toothpaste, and replaced the o rings and seals. Got my fingers crossed, but it hasn't leaked in the past.