Rebuilt petcock leaking
Moderator: rztom
- Consciousness
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- Location: The Big Apple
Rebuilt petcock leaking
Hi all, I have noticed a puddle of fuel and a drained tank since the cold weather hit, I have recently rebuilt the petcock with a kit from economy and it was working fine in the warm weather, any ideas as to what's going on?
Thanks
Thanks
85 RZ350 KR. Racetech/Fox Motul 10W. Telefix, Prog. Zeel, VForce4's, VM30 Mik's Uni-Filters & UFOs, Grooved Head & Mild Port w/Boyesen's by Rich's Taylor'd Porting, Orig. Toomeys, Redline, Conti Attack2.
Re: Rebuilt petcock leaking
Do the petcock mod and get rid of the vacuum port.
- Consciousness
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- Joined: Sun Jul 21, 2013 12:28 pm
- Location: The Big Apple
Re: Rebuilt petcock leaking
Thanks mkane, nice that I can keep the stock fuel dial, that was the reason I went the rebuild route over the pingle. Here's the post just in case others need it http://www.usa2strokers.com/forum/forum ... dification
85 RZ350 KR. Racetech/Fox Motul 10W. Telefix, Prog. Zeel, VForce4's, VM30 Mik's Uni-Filters & UFOs, Grooved Head & Mild Port w/Boyesen's by Rich's Taylor'd Porting, Orig. Toomeys, Redline, Conti Attack2.
Re: Rebuilt petcock leaking
Great mod. Suggestion, don't relabel the petcock so potential thief's/joy riders have no clue what they are doing.
Rory
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine
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- Posts: 28
- Joined: Thu Sep 06, 2012 5:12 am
- Location: Melbourne
Re: Rebuilt petcock leaking
I have a leaking petcock. I've tried rebuilding it, cleaning it etc, I've added a little more tension to the wave washer, there's no damage or wear evident, and whilst at first it looked hopeful, after a run, I've found it still leaks. A new petcock is too expensive. I've read bad reviews of the repair kits that are available (?). I see the inline fuel tap (Briggs and Stratton -ouch!) option. Nice, cheap and cheerful, -It may come to that.
Regarding this mod:
http://www.usa2strokers.com/forum/forum ... dification" onclick="window.open(this.href);return false;
Removing the vacuum system obviously this works for some people, but can someone explain why/how it works? Surely if the petcock leaks it must be caused by the rubber seal gasket and or a weak wave washer that 'makes' the seal, irrespective of the vacuum line? How does bypassing the vacuum line fix the leak?
Regarding this mod:
http://www.usa2strokers.com/forum/forum ... dification" onclick="window.open(this.href);return false;
Removing the vacuum system obviously this works for some people, but can someone explain why/how it works? Surely if the petcock leaks it must be caused by the rubber seal gasket and or a weak wave washer that 'makes' the seal, irrespective of the vacuum line? How does bypassing the vacuum line fix the leak?
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- Posts: 28
- Joined: Thu Sep 06, 2012 5:12 am
- Location: Melbourne
Re: Rebuilt petcock leaking
Well I've tried something else which has worked (SO FAR !) - but I'm getting an in-line on-off tap anyway, - Festo brand 6mm inline ball-valve which are used in industrial applications and model jet turbine aircraft applications, so should be good quality. So anyway, I pulled the tap backplate off, which gives access to the fine spring that holds the vacuum plunger which has the small o-ring into the aperture which stops fuel flow. I thought maybe if the spring has lost some tension it might fail to hold it with enough pressure to seal the hole. So I gently pulled the spring to lengthen it a bit. Reassembled, and it works well so far, -it's stopped the drip from the fuel tap outlet.
BTW a mate of mine has converted plenty of fuel taps, and instead of Lumiwelding, he drives in a suitably sized bearing ball into the hole to blank off the vacuum.
BTW a mate of mine has converted plenty of fuel taps, and instead of Lumiwelding, he drives in a suitably sized bearing ball into the hole to blank off the vacuum.
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- Location: Spielberg (Austria)
Re: Rebuilt petcock leaking
Seems that it is a common problem...
I have also rebuilt my petcock but it`s still leaking - Checked everything, vacuum valve seat is in good condition.
Combined with slightly leaking needle valves it leads to fuel on the garage floor.
I think the problem is the O-ring of the vacuum valve.
There are differend hardeness grades available, maybe the rebuild kits use too hard standard O-rings for the vaccum valve.
Problem: It needs more force to seal, but a stronger spring would be a risk because it may not open with the available vacuum.
Maybe i will try a softer o-ring in future, but at the moment the additional in line fuel tap from a Honda lawn mower works good :)
By the way - at the moment there are temperatures from 25-36°C (night/day) in Austria - some days ago i forgot to close the lawn mower fuel tap, but there was no fuel on the floor in the morning.
Seems that it also works fine on my bike as long as the temperatures are high enough.
I have also rebuilt my petcock but it`s still leaking - Checked everything, vacuum valve seat is in good condition.
Combined with slightly leaking needle valves it leads to fuel on the garage floor.
I think the problem is the O-ring of the vacuum valve.
There are differend hardeness grades available, maybe the rebuild kits use too hard standard O-rings for the vaccum valve.
Problem: It needs more force to seal, but a stronger spring would be a risk because it may not open with the available vacuum.
Maybe i will try a softer o-ring in future, but at the moment the additional in line fuel tap from a Honda lawn mower works good :)
By the way - at the moment there are temperatures from 25-36°C (night/day) in Austria - some days ago i forgot to close the lawn mower fuel tap, but there was no fuel on the floor in the morning.
Seems that it also works fine on my bike as long as the temperatures are high enough.
My Bikes:
Yamaha RD500 1985
Yamaha RD350 1985
Yamaha R1 2001
Honda CBR 1000 2006
Yamaha RD500 1985
Yamaha RD350 1985
Yamaha R1 2001
Honda CBR 1000 2006
Re: Rebuilt petcock leaking
Guess I took a shortcut, just removed the plastic 'spacer' bit, made one screw shorter, put back together, seems good, only have pri, fine with me.
O no, red pilled.
- Evans Ward
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- Location: Macon, GA
Re: Rebuilt petcock leaking
Silverstrom/ John gave me a tip some time back- save yourself the time and trouble of rebuilding which may still leak and buy a new petcock still available from Yamaha. Peace of mind and no leaks!
84 RZ350-Toomeys,SCR milled head, stk 26 carbs,300 M, 35 P, stock regrooved needles AS 2.5 turns out,stk air box,Banshee reeds Zeel non-progr CDI,TSRL Program YPVS,alum rad,R6 shock,GV emulators w/RT springs,fork brace,Shindy steering damper.
Re: Rebuilt petcock leaking
Can someone tell me the dimensions of the diaphram spring including wire sectional thickness? thanks
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- Joined: Thu Sep 06, 2012 5:12 am
- Location: Melbourne
Re: Rebuilt petcock leaking
The links to the 'petcock shutoff modification' are u/s, and nothing relevant by that name comes up in a search,
Can anyone give us a link to the instructions please?
I just blanked off my vacuum line and use PRI for on and any other position as Off.
But there's no reserve with this setup, maybe there is there a better way?
Can anyone give us a link to the instructions please?
I just blanked off my vacuum line and use PRI for on and any other position as Off.
But there's no reserve with this setup, maybe there is there a better way?
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- Joined: Thu Jun 19, 2014 9:52 pm
Re: Rebuilt petcock leaking
viewtopic.php?f=21&t=13677" onclick="window.open(this.href);return false;
Here is how I fixed mine and it works like a champ....RD 400.petcocks are cheap and available....sorry the pics are.gone with the demise of photo bucket...
Here is how I fixed mine and it works like a champ....RD 400.petcocks are cheap and available....sorry the pics are.gone with the demise of photo bucket...
I love the smell of Blue Marble in the morning!
Tim Steele in Front Royal, VA
Tim Steele in Front Royal, VA