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Discussion Starter #1 (Edited)
TRX350 (86-89) Petcock Rebuild Works!!!

My petcock leaked thru the handle so bought a replacement inner gasket thinking it might be the only replaceable part. The kit came with two screws to replace the rivets. I drilled out the rivets before realizing I used a larger diameter bit than the kit screws came with. Cut off the rivet heads and disassembled the petcock--here's what to see.

The rotating positioning piece of the petcock contacts the gasket and directs flow from the main or reserve pipe, or to a blocked position for OFF. I've cleaned up the parts but also noticed a grooved oring on the positioner. I hope this doesn't become a problem. Also the new gasket is a smaller diameter than the old one.
 

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Discussion Starter #2 (Edited)
Ok so I cleaned and used aluminum polish on all the mating surfaces. Drilled thru the rivets all the way thru the back of the housing; if I had a do-over I would drill/tap to screws in the kit. Tapped holes for 6mm x 32 threaded screw. Reassembled without Hondabond just to see if it will hold a seal.

I tightened the screws pretty good and the action seems smooth. Put water in the tube and no leaks. Now to try fuel.
 

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Discussion Starter #3 (Edited)
Corrected measurements and drawings crude as they are:
The base gasket in the rebuild kit i bought is a smaller diameter than original but that doesn't mean it will leak. Grooved oring on the petcock position selector (lever gasket) may keep the lever exactly centered and prevent leaks as well.

Base gasket appx 1 2/32" OD x 3.5/32" thick (2.74 cm OD x 0.275 cm) (measured from my old one). Could go up to 4/32" thick as there are some raised edges around the perforations

Lever gasket appx 1 4/32" OD x 1.0" ID x 2.5/32" thick
(2.85cm OD x 2.55cm x 0.20 cm).

Two petcock mounting oring 16077-HA7-671:
Appx 0.45" OD x 0.325" ID x 2.5/32" (1.15 cm OD x 0.80 ID x 0.20 cm). These orings could go a bit larger and thicker but not smaller or thinner.
 

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I think I would have just bought a used pet cock, and been done with it..lol. I guess you got a lot of free time though :).
 

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Discussion Starter #5
There's a guy selling gaskets so mebbe I can find a way to rebuild petcocks. It was 11 degrees and snowing so got out my calipers and calculator!! LOL now to have a homebrew.
 

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Yeah I'd have to be pretty desperate lol I'd pay big money for OEM NOS cosmetic things IF I was restoring a machine to original, like plastics or decals, accessories, stuff like that. But stuff you can find used in good working order or even rebuild that nobody will ever see? Not spending that kind of cash.


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My petcock leaked thru the handle so bought a replacement inner gasket thinking it might be the only replaceable part. The kit came with two screws to replace the rivets. I drilled out the rivets before realizing I used a larger diameter bit than the kit screws came with. Cut off the rivet heads and disassembled the petcock--here's what to see.

The rotating positioning piece of the petcock contacts the gasket and directs flow from the main or reserve pipe, or to a blocked position for OFF. I've cleaned up the parts but also noticed a grooved oring on the positioner. I hope this doesn't become a problem. Also the new gasket is a smaller diameter than the old one.
I've taken one apart and cleaned it out by drilling out the rivets and replacing them with screws. I've also ruined one when I got off center with the drill.

Used ones are a crapshoot, and new ones are $$, so fixing the existing one, if possible, is a great alternative.
 

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My petcock leaked thru the handle so bought a replacement inner gasket thinking it might be the only replaceable part. The kit came with two screws to replace the rivets. I drilled out the rivets before realizing I used a larger diameter bit than the kit screws came with. Cut off the rivet heads and disassembled the petcock--here's what to see.

The rotating positioning piece of the petcock contacts the gasket and directs flow from the main or reserve pipe, or to a blocked position for OFF. I've cleaned up the parts but also noticed a grooved oring on the positioner. I hope this doesn't become a problem. Also the new gasket is a smaller diameter than the old one.
I've taken one apart and cleaned it out by drilling out the rivets and replacing them with screws. I've also ruined one when I got off center with the drill.

Used ones are a crapshoot, and new ones are $$, so fixing the existing one, if possible, is a great alternative.
I will agree, sometimes we gotta do..what we gotta do to make parts work. I've done some crazy stuff in my years, in this bizz, you must think outside the box at all times !..lol.
 

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shadetree wrote: I will agree, sometimes we gotta do..what we gotta do to make parts work. I've done some crazy stuff in my years, in this bizz, you must think outside the box at all times !..lol.

Yep, when you get into stuff that is obsolete and NLA and even NOS stuff 30 years old might be bad due to dried out seals, rubber parts dry cracked, etc.
I've seen quite often carbs that were running good, removed and stored, then no good when re-installed later due to dried out parts.

I would not give that guy $300 for his petcock if it was the last one in the world, and I also keep a heads up for them type and not let them sneak up behind me and try to catch me with my britches down.

Happy New Years
 

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Discussion Starter #12 (Edited)
Ok I updated the measurements and photos--units in standard and metric. I am interested to hear of anyone's success in finding parts.

Finding I need to put the measurements into millimeters as that will improve chances of getting correct gaskets
 

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Discussion Starter #13
Ok I found a petcock rebuild kit that has the correctly sized seals and includes the gaskets needed to mount to the fuel tank. I haven't finished putting mine together but with a little oring grease I think this is going to work! Will install this weekend!
 

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Discussion Starter #14
No leaks; a bit stiff to turn but that was expected cuz I am pretty good at tightening. No Hondabond used. Off to ride!!
 

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Discussion Starter #15 (Edited)
I'm doing a second rebuild.

Check it out I used a very small drill, #55, in the center of the rivet to keep me on center. At least a quarter inch. Then I drilled off the head of the rivet so I could remove the cover. It is not glued on. That left a bit of rivet stem
I used a drill and jewelry file to remove the stem and level dress the surface.

Now ready to drill and tap for screws but wanted to share how tightly fitted the rivets are into the housing
 

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I'm doing a second rebuild.

Check it out I used a very small drill, #55, in the center of the rivet to keep me on center. At least a quarter inch. Then I drilled off the head of the rivet so I could remove the cover. It is not glued on. That left a bit of rivet stem
I used a drill and jewelry file to remove the stem and level dress the surface.

Now ready to drill and tap for screws but wanted to share how tightly fitted the rivets are into the housing
Yes, must take additional care getting the very hardened steel rivets out or a ear can be easily broken off or damaged. and the rivet body after the head is drilled off is still very tight in the aluminum ear and the rear of the ear needs supported when drifting out the rivet body AND replacements for the 86-89 years are NLA from Honda and NOS petcocks when found are priced out of sight ($300+) and used ones usually leak due to the internal seals being dried out or worn out and will require the surgery you are mentioning so as to install a rebuild kit)

Kinda strange that the rivets are hardened steel in a pot metal body petcock.
 

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Discussion Starter #17
Going to try the 4mm x 40 screws from the kit even though I think a 6mm x 32 x 3/8" long is the best fit. I drilled straight thru the housing Okie cuz I didn't want to risk stripping the tapped hole. I will fill the holes with honda bond.
 

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Discussion Starter #18 (Edited)
Turns out they aren't 4mm x 40 so I didn't have the right tap. So I drilled and tapped for the 6mm x 32 x 3/8". Fits well and more importantly centered on the faceplate. Ready to test I need a vacuum tester like Okie!
 

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Turns out they aren't 4mm x 40 so I didn't have the right tap. So I drilled and tapped for the 6mm x 32 x 3/8". Fits well and more importantly centered on the faceplate. Ready to test I need a vacuum tester like Okie!
Right about being careful here and keeping it centered. That is why the steel rivets are so snug in the ears.

I'm just going from memory since it's been couple months, but I think maybe that to make sure all was centered after tapping the rivet holes for machine screws that I left one of the rivets in place and tapped the first one straight thru both the top and bottom ear using a 6-32 tap and then inserted a machine screw to hold in place and then removed the other rivet and tapped the other side and after both ears were tapped thru placed witness marks on the outside of all pieces and I removed the screws and center rotating piece for the first time and carefully used a body drill for the 6-32 screws in the outer retainer. I placed witness marks on all the pieces as they were being removed so as to go back together in same sequence and indexed properly.
Seems like a lot of trouble repairing a small piece, but it's a NLA dinosaur egg you are working on and NOS when found is expensive and used ones usually leak due to being old and seals dried.

If the proper centering is not carefully maintained when replacing the rivets with screws the rotating part will not properly compress the small outer seal around it's edge.:eek: (and back to looking for another obsolete dinosaur egg to repair)
 

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Discussion Starter #20 (Edited)
Bought a great little jewelers bench drill at auction. Used it, with a #55 cobalt bit to perforate the rivets in the housing of the fuel petcock. Allows me to center perfectly and slowly thru the body of the petcock. Regular drills run so fast the metal would melt to the bit

This is the sixth petcock I've rebuilt
 

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