Petcock rebuild kit or replacement

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Dan_Austin
Posts: 43
Joined: Thu Nov 17, 2005 2:16 am
Location: San Jose, CA

Petcock rebuild kit or replacement

#1 Post by Dan_Austin » Sat Nov 18, 2006 3:33 am

I recently found my RZ had decided to dump the entire contents of it's gas tank into right-front cylinder while sitting.

Thinking that I was past due to replace the needle and seats, I swapped in four new units, adjusted the floats and refilled the tank. Two days later the tank was almost empty and the garage floor was good and wet with
gas.

It should have clicked right away, but it took the second tank to remind me that the RZ has a vacumn operate petcock. Any hints on rebuilding the stock unit or a recommended replacement?

I did find an ancient post about the possibility of disassembling the stock unit and putting it together in a manner that would provide on/off/reserve
without a vacumn source. Does anyone have experience with this?

ALAN
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#2 Post by ALAN » Sat Nov 18, 2006 5:53 pm

Dont know where you are but new seal for petcock cost less than 2 pound sterling.

Dan_Austin
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Joined: Thu Nov 17, 2005 2:16 am
Location: San Jose, CA

#3 Post by Dan_Austin » Sat Nov 18, 2006 10:35 pm

San Jose, CA.

I had heard that the seals/rebuild kits were no longer available. I guess
I'll try the usual suspects for RZ parts here in the states...

marbil
Posts: 17
Joined: Wed Nov 16, 2005 11:54 pm

petcock rebuild or replace

#4 Post by marbil » Sun Nov 19, 2006 12:12 am

regardless if the petcock is stopping the flow of fuel the floats if operating correctly should shut the fuel off. I found that if I put my bike on a padock stand the floats will ocassionaly let fuel by. may be that after 25 years of leaning on a side stand they dont like seating in the straight up position.
I got a rebuild kit for my petcock about 6 months ago from Bobs motorsports in Canada they had it in stock. hasnt leaked again so I havent rebuilt them yet. let me know if you cant find info on Bobs and I will dig it up for you I have the part #'s also if you need
Do you smell smoke?

Mike A
Posts: 1
Joined: Fri Dec 01, 2006 1:57 pm
Location: Toronto Ontario

Petcok Rebuild Kit

#5 Post by Mike A » Wed Dec 06, 2006 4:23 pm

I just had the same thing happend lost all the gas.
I went to the dealership and asked for a petcok
rebuild kit and they said no such thing.
Could you post the part numbers you have.

Thanks Mike

Dan_Austin
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Location: San Jose, CA

#6 Post by Dan_Austin » Fri Dec 08, 2006 1:42 am

I was also informed that rebuild kits do not exist, but the only critical part (or commonly critical) is the rubber gasket/valve that goes behind the petcock lever.

I turned to Dale Murphy who knew what I needed and just happened to have one in stock. I never bothered with the part number.

I ended up pulling the back off the petcock to check it and clean it, but
I really didn't need to.

Don't loose the tension spring located under the lever retainer. My slipped under the bike and I didn't notice it the first time I reassemble the petcock, and of course it still leaked...

Luther
Posts: 387
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Location: Obamagrad, Oklahoma

#7 Post by Luther » Fri Dec 08, 2006 6:37 pm

The problem I had was with the vacuum valve on the backside of the petcock. Take the cover off and there is a shaft with an O ring and a spring holding it closed. It doesn't seal worth a damn and gives a constant supply of fuel 24 hours a day. If you also have a bad float needle and seat in one of the carbs expect to find a pool of gas or a burned down house when you come home.

What I did was push the shaft with O ring past the tapered seat into the petcock with my thumb till it bottomed out. The vacuum valve is now disabeled and won't leak. Put the spring and cover back on. On the front of the petcock take the 2 screws, wave washer and selecter lever out and reasemble them rotated 180 degrees. Now it should have on, off and reserve. It also flows a whole lot more fuel.

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zalienz
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#8 Post by zalienz » Sun Nov 02, 2008 11:37 pm

I need to give you some big kudos for that Luther.

My petcock has never shut off, and it has been a lot worse lately, bad enough to keep a pan under the bike to catch dripping fuel. Not to mention the whole garage smelled like raw fuel..... had me worried.

Your mod fixed it for good, and I feel much better about having a petcock that I can manually shut off. Thanks!
RZ500
RD400

Whether you think you can, or you think you can't, either way, you are right -Henry Ford

Motolli
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Re: Petcock rebuild kit or replacement

#9 Post by Motolli » Fri Jul 14, 2017 12:49 pm

I did this today also. Works perfectl!! If the aluminum cylinder won't go through the hole, because it is some tenths of a millimeter too thick ( in my case 8.2 hole is 8.0 ) just use an extra strong spring to press the o-ring into the seat. Perfect !

Luther
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Re: Petcock rebuild kit or replacement

#10 Post by Luther » Thu Sep 26, 2019 6:27 pm

Thanks Motolli. I got another petcock years ago and it didn't fit. Always wondered how many folks got miss led by this.

lost1750GTV i'm answering your post from Vendors here. viewtopic.php?f=10&p=100457#p100457

I don't like to give bad information so reread here to see if vacuum line disconnect was mentioned and it is briefly. I've wondered if the pushed in past the taper diaphragm rod can work its way out over time. Like a full tank in the sun building pressure. A solid stop instead of spring would be better. So mine is seeping again and i'm going to pressure test it before take apart

lost1750GTV
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Re: Petcock rebuild kit or replacement

#11 Post by lost1750GTV » Fri Sep 27, 2019 8:34 am

thanks , Luther.
I read a lot here, sometimes miss/forget things.

Luther
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Re: Petcock rebuild kit or replacement

#12 Post by Luther » Sun Sep 29, 2019 11:00 pm

"I read a lot here, sometimes miss/forget things."

I've got you beat on that. Wait, what were we talking about?

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JonW
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Re: Petcock rebuild kit or replacement

#13 Post by JonW » Wed Oct 23, 2019 10:36 pm

Does anyone know if this unit fits? It looks 'right' but maybe is a bit wide?

https://www.ebay.co.uk/itm/PRE-ORDER-30 ... SwMoVdHv3K
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rd84
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Re: Petcock rebuild kit or replacement

#14 Post by rd84 » Fri Oct 25, 2019 12:30 pm

To rebuild the vacuum fuel tap/ petcock use the viton kit from NRP - it’s not cheap but it is ethanol resistant - it’s worked very well so far on my RD500

Cascade500
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Re: Petcock rebuild kit or replacement

#15 Post by Cascade500 » Mon Oct 28, 2019 11:59 pm

JonW wrote: Wed Oct 23, 2019 10:36 pm Does anyone know if this unit fits? It looks 'right' but maybe is a bit wide?

https://www.ebay.co.uk/itm/PRE-ORDER-30 ... SwMoVdHv3K
It doesn’t fit. Even though it looks wide, it’s actually too narrow. The o-ring seal that seals the Petcock to the tank is 4X8-24512-00, which also fits Petcock 4JT-24500-20. I bought one of the 4JT Petcock used to try, and it’s too narrow.

Cheers,

Dirk

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