- Posts: 5
- Thank you received: 0
Vacuum actuated petcock does not stop fuel.
- Willie
- Topic Author
- Offline
- User
When I put everything back together and started putting fuel in the tank it spewed from between the petcock body and the vacuum assembly.
I disassembled the petcock and installed the boot over the new vacuum assembly, over the o-ring and reinstalled. No leaks!!!!
A few days later I went to remove the tank to work on an electrical problem, and found that the petcock does not stop the fuel.
Now the questions: Will this cause me any problems in the future? If so, what are they? Where can I get the right vacuum assembly (dealer has no clue)?
Thanks for your help.
Please Log in or Create an account to join the conversation.
- KZQ
- Offline
- Administrator
- Walking Behind the Corn May Not Be All That!
- Posts: 4833
- Thank you received: 1415
To answer your question: Yes it's important that the petcock function correctly. If the petcock allows the fuel to continue running It's possible to fill the crankcase with a gas/oil mixture, or even worse, it's possible to hydraulically lock a cylinder when you hit the starter.
KZCSI
Post edited by: KZCSI, at: 2007/04/26 13:32
www.KZ1300.com
Riders:
1968 BSA 441 Shooting Star, 1970 BSA 650 Lightning, 1974 W3, 1976 KZ900, 1979 KZ750 Twin, 1979 KZ750 Twin Trike, 1981 KZ1300, 1982 KZ1100 Spectre, 2000 Valkyrie, 2009 Yamaha Roadliner S. 1983 GL 1100
Projects:
1985 ZN1300
Please Log in or Create an account to join the conversation.
- Pterosaur
- Visitor
A common source of seepage with these birds is a lack of tension on the shutoff spring (#92081 in the pic below). When the motor shuts down and the carb vent quits drawing on the diaphram, the spring presses the diaphram closed and shuts off flow. At least that's how it's supposed to work anyway.
Might be worth pulling it apart again and giving that spring a bit of a stretch - they tend to weaken over time and don't put out quite as much as they did when they were younger.
Please Log in or Create an account to join the conversation.
- Willie
- Topic Author
- Offline
- User
- Posts: 5
- Thank you received: 0
When I tried the dealer supplied parts (as seen in your diagram) fuel spewed everywhere, no seal at all between the diaphragm assembly to the petcock body. I added the boot over the dealer part and no exterior leak, but it does not seal internally.
Now the question is where can I get a diaphragm assembly with such a boot? The dealer is lost.
Post edited by: Willie, at: 2007/04/26 14:43
Post edited by: Willie, at: 2007/04/26 14:47
Please Log in or Create an account to join the conversation.
- Pterosaur
- Visitor
My problem rests with part number 43028 and o-ring 670. The original vacuum diaphragm did not look exactly like 43028, and did not have the o-ring 670. Instead it had a neoprene boot that covered the shaft that o-ring 670 fist on, and sealed both the vacuum diaphragm assembly to the petcock body and the fuel inlet when there was no vacuum.
Ah. My bad - I just had the drawing for the KZ1000 petcock lying around and went on the assumption that they'd be similar critters.
Similar, but not similar enough. :blush:
Now the question is where can I get such a thing?
Don't rightly know offhand, but there's some pretty fair 650 hands around that are sure to have better ideas than mine...
Please Log in or Create an account to join the conversation.
- Willie
- Topic Author
- Offline
- User
- Posts: 5
- Thank you received: 0
Please Log in or Create an account to join the conversation.
- Pterosaur
- Visitor
Me being what I am - generally a seeker of the path of least resistance, I'd suggest picking up one of those "other models" somewhere if the mount's the same.
There's probably at least a dozen people around here that'll home in on this thread that have one lying around in workable/rebuildable shape that'll make you a deal on it.
Please Log in or Create an account to join the conversation.
- RetroRiceRocketRider
- Offline
- User
- ...bring in the machine that goes PING!
- Posts: 1641
- Thank you received: 29
It sure beats the frustration and aggravation of "Mickey Mousing" it and finding out that it only partially works, or created a leak elsewhere as you're experiencing
Please Log in or Create an account to join the conversation.
- davenkids2001
- Offline
- User
- Posts: 150
- Thank you received: 2
Mine's an El Cheapo Briggs+Stratton lawnmower type that I put in my gas line after my petcock. It works great, just gotta remember to turn it off. It was about $7.
Dave and Janet
Great Lake State
1979 650SR
Please Log in or Create an account to join the conversation.
- fathom
- Offline
- User
- Posts: 1
- Thank you received: 0
Had image of being hit by a Tiger Tank with one back-fire.
What can cause this raw gasolene gush?
- Stuck float in tank due to emptying it for winter storage?
- The turn off valve over engeneered?
- ule tank needle valve out of seat inside the tank?
- Free-flow from a bad design in 1996 which should have been a recall?
One of the carbs needle valves stuck open with varnish?
Or !
Tanked Leprecaughns vacationed in the tank, so I should just drink the Potsheen and shut-up...but dont start her up and spoil their fun?
Jack O'Brien
If no help my friends, then it's up to the shop with $500.00 so there goes the Nova Scotia ride this summer. Mercy me
Please Log in or Create an account to join the conversation.
- N0NB
- Offline
- User
- Blue handles better
Willie, a relatively simple fix is to go with a manual fuel tap. Z1 Enterprises has a Pingle adaptor plate (44 mm bolt spacing on my SR) that will allow you to install a fuel tap with 3/8" NPT thread. They also offer a generic manual manual petcock that is about 15 bucks.
For about $30 you can forget about the vacuum job. Most likely, once you kit it and get that part to work properly, it will do as both of mine did and start leaking where the elbow comes out of the petcock body.
With the manual tap, you're in control of the fuel flow, so you need to remember to turn it on!
Nate
Nates vintage bike axiom: Riding is the reward for time spent wrenching.
Murphys corollary: Wrenching is the result of time spent riding.
1979 KZ650 (Complete!)
1979 KZ650 SR (Sold!)
1979 KL250 (For sale)
1994 Bayou 400 (four wheel peel )
Please Log in or Create an account to join the conversation.
- Willie
- Topic Author
- Offline
- User
- Posts: 5
- Thank you received: 0
It is starting to have either timing chain or cam chain tensioner problems. It is rough at idle, but when you give it a bit of throttle it smoothes out. I replaced the plugs, wires are in excellent condition, replaced the points (whole plate), and adjusted the timing. When I put a timing light on it you can see the mark position is unstable at idle. If you give it just a little throttle the line stabilizes nicely. I have set, checked, reset, and rechecked the points gap and timing adjustment.
I got tired of working on the thing so… I bought a 2006 Vulcan 900 and have been smiling ever since!!! My Father-in-law has been riding the KZ back and forth to work and around town. It continues to run well.
I have had time to ride both bikes back to back, and the KZ definitely has its high points. It is just as quick, good power to weight ratio, has better handling, and seems to be more stable on uneven surfaces and in windy conditions. The problems with the KZ are: the bike is not comfortable over about 65mph (it seems to be working really hard), and I have to work on it all the time.
We will probably just ride it until something goes wrong that can’t be easily fixed.
Ride it until it dies!!!:evil:
Please Log in or Create an account to join the conversation.