Author Topic: Replacing rubber on aftermarket petcocks with OEM  (Read 1110 times)

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Offline Tugboat

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Replacing rubber on aftermarket petcocks with OEM
« on: March 27, 2017, 01:15:27 PM »
I've got a newish aftermarket petcock that (of course) leaks. Has anyone had any luck with replacing the 4-hole rubber gasket that goes behind the lever on one of these with an OEM Honda one?
If it's worth doing, it's worth doing twice.

Offline grcamna2

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Re: Replacing rubber on aftermarket petcocks with OEM
« Reply #1 on: March 27, 2017, 01:28:59 PM »
Got any pics of it, what bike is it from ?  I've drilled-out rivets and tapped for small 3mm screws and it's worked good for me on many different fuel valve/petcocks.I was even able to look around and find a matching OEM rubber packing that fit well and no problems ever since;that China rubber is junk.
I do this to original OEM petcock valves,never tried re-habbing a china one.
« Last Edit: March 28, 2017, 06:56:22 AM by grcamna2 »
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline DaveBarbier

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Re: Replacing rubber on aftermarket petcocks with OEM
« Reply #2 on: March 28, 2017, 04:56:02 AM »
Is the petcock riveted? You can drill out the rivets and replace with screws and nuts. There's normally a little warped spring washer back there too, sometimes you can just bend it a bit more to add pressure and reuse the old rubber.

Offline drumstyx

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Re: Replacing rubber on aftermarket petcocks with OEM
« Reply #3 on: March 28, 2017, 07:51:01 AM »
I screwed up drilling out the rivets on my OEM petcock (First time I'd ever drilled out a rivet...didn't realize I just needed to drill off the head) So I'd have to use some rather fat screws to rebuild it. I put an aftermarket petcock on, and it's been fine so far. Leaking at the threads, but that's my own fault for not sealing them up...they're a bit rusty, so I can't expect a perfect seal there.

Offline BWC

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Re: Replacing rubber on aftermarket petcocks with OEM
« Reply #4 on: March 28, 2017, 09:08:02 AM »


I have the same sort of question.
I have seen an aftermarket seal kit for these OEM Honda petcocks available, but per chance has anyone found an available Honda part for replacements? Left one is from my 78 750F and right one is from my 81 900F. I managed to take apart the 81, turn the packing over and get a bit more use out of it but I have since replaced it with an aftermarket one. Just like to be able to rebuild them as spares.
750 packing size is app. 20mm x 2.8.  900 is 21.5 x2.8. Sizes could be a bit off as the rubber is pretty hard.

Offline Tugboat

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Re: Replacing rubber on aftermarket petcocks with OEM
« Reply #5 on: March 28, 2017, 09:09:56 AM »
The petcock for 70-76 CB750's (also happens to fit my KZ400). It will come apart with no issues - I was just wondering if anyone had tried to fix a Chinese knockoff like this before.
If it's worth doing, it's worth doing twice.

Offline grcamna2

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Re: Replacing rubber on aftermarket petcocks with OEM
« Reply #6 on: March 28, 2017, 10:14:30 AM »
BWC,
 I looked on motogrid.com at their online parts description diagrams for a replacement OEM 'packing' on multiple bikes and then looked on Ebay,etc. for just the packing;it took a bunch of looking to get the correct oem part but finally I found one that was a replacement(correct size) for my OEM Honda petcock from a Honda model that had a replaceable rubber part like this.
I started a thread & asked this question here and waited for a response.. I know some on here have done this before but never heard back.There is one member here 'Scott S' who was going to Barber's and i asked him if I could send my old one to him so he could find me a few from a vendor there and he did help  :)
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline grcamna2

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Re: Replacing rubber on aftermarket petcocks with OEM
« Reply #7 on: March 28, 2017, 10:18:47 AM »
The petcock for 70-76 CB750's (also happens to fit my KZ400). It will come apart with no issues - I was just wondering if anyone had tried to fix a Chinese knockoff like this before.

I tried doing this Tug, the China petcock has a similar dia. but just different enough so you can't use the OEM size to make it work;can you rebuild your original OEM ?
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
  I love the small ones too !
Do your BEST...nobody can take that away from you.

Offline BWC

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Re: Replacing rubber on aftermarket petcocks with OEM
« Reply #8 on: March 28, 2017, 03:37:28 PM »
BWC,
 I looked on motogrid.com at their online parts description diagrams for a replacement OEM 'packing' on multiple bikes and then looked on Ebay,etc. for just the packing;it took a bunch of looking to get the correct oem part but finally I found one that was a replacement(correct size) for my OEM Honda petcock from a Honda model that had a replaceable rubber part like this.
I started a thread & asked this question here and waited for a response.. I know some on here have done this before but never heard back.There is one member here 'Scott S' who was going to Barber's and i asked him if I could send my old one to him so he could find me a few from a vendor there and he did help  :)

Thanks for the info.
I do understand that the dealers aren't keen on just pulling random parts to see if they can match one up. They really like part numbers  ;)
Since these shut model offs aren't supposed to be serviceable, there are no OEM listings for the packings it seems.