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Discussion Starter #1
Has anyone actually taken the fuel petcock on a 1987 GL1200 apart and put a rebuild kit 4-hole disc and gaskets in it?

I'm trying to find out of they use the same rebuild kit parts as a 1984, 1985, and 1986 GL1200 fuel petcock. If they don't, we 1987 owners are just plain screwed if our fuel petcocks spring a leak.

Here's what I've found out so far:

The 1987 fuel petcock (PN 16950-ML8-601) is definitely a different part than the fuel petcock (PN 16950-MG9-005) for a 1984, 1985, or 1986 GL1200.

The obvious things that are different are:

1. The fuel outlet on the 1987 petcock is 3/8" (10mm fuel hose), while the fuel outlet on the 84, 85, 86 is 1/4" (5.5mm fuel hose). So the fuel hoses that fit are not the same. (Not exactly a deal breaker.)

2. The distance between the mounting screw holes is different: the 1987 petcock mounting holes are approximately 46mm apart,while the 84, 85, 86 petcock mounting holes are about 42mm apart. So they won't mount on an '87 fuel tank and vice-versa.

3. The entire body of the 1987 fuel petcock is larger than an 84,85,86 fuel petcock. The 1987 petcock body diameter is 32mm. The 84, 85, 86 petcock body diameter is 28mm. So, they are 4mm smaller.

The 4-hole disc (PN 16955-268-020) that comes in a rebuild kit for the 84, 85, 86 fuel petcock is 20mm in diameter. That's the issue that worries me. Will that disc fit in a 1987 fuel petcock properly, or is the 4-hole disc for a 1987 fuel petcock actually larger in diameter to fit the larger fuel petcock and flow more fuel?

I have a rebuild kit for an 84,85, 86 GL1200 that includes the 4-hole disc (PN 16955-268-020). The '87 fuel petcocks are riveted together and not designed to be rebuilt. (Though many other Honda petcocks are as well, but can be drilled out, rebuilt, and reassembled with screws. I've done many that way.)

If I take mine apart and the 4-hole disc doesn't fit, I'm basically screwed. NO one, and I mean NO one has a 1987 GL1200 fuel petcock for sale on planet earth. I've checked all of my many sources, including vintage bike parts suppliers and my "special" one in Norway.

So, has anyone successfully taken apart a 1987 GL1200 fuel petcock and rebuilt it using a rebuild kit for an 84, 85, or 86?


Thanks for any advice or experience on this issue.

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Yes, I took mine apart and rotated the 4 hole thingy. Plus I put plumber's tape in the outer seal groove to stop it from leaking.

And no, the 4 hole seal that you can buy will not fit the '87. '87 is much larger.

The biggest challenge is drilling out the stud things that hold the two halves together, then drilling and tapping for reassembly.

You can try and find a used part on eBay, too, just is case.

I used to have some pics but can't find them now. :baffling:
 

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Discussion Starter #3
Yes, I took mine apart and rotated the 4 hole thingy. Plus I put plumber's tape in the outer seal groove to stop it from leaking.

And no, the 4 hole seal that you can buy will not fit the '87. '87 is much larger.

The biggest challenge is drilling out the stud things that hold the two halves together, then drilling and tapping for reassembly.

You can try and find a used part on eBay, too, just is case.

I used to have some pics but can't find them now. :baffling:
Thanks much Dennis! I was hoping you'd chime in on this problem.

At least that confirms that the 4-hole disc for the earlier GL1200s will not fit. I suspected that might be the case.

Mine is only leaking when in the OFF position and that just started recently. She doesn't get ridden as much as she used to so things will start stiffening up! Hah! Don't I know it! Same thing is happening to me!

I thought about rotating the 4-hole disc 180 degrees since that would flip the two holes in the disc that are actually being used. I may have to give that a try.

For now, I just don't turn the petcock off and no leaks. But that means only your float valves are keeping the fuel from overfilling the carbs and running into the cylinders and possibly causing a hydro-lock on the next attempted start-up. That would be BAD! :surprise:

Thanks for the reply. I'll have to decide if I want to open her up!

Bob
 

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Thanks much Dennis! I was hoping you'd chime in on this problem.

At least that confirms that the 4-hole disc for the earlier GL1200s will not fit. I suspected that might be the case.

Mine is only leaking when in the OFF position and that just started recently. She doesn't get ridden as much as she used to so things will start stiffening up! Hah! Don't I know it! Same thing is happening to me!

I thought about rotating the 4-hole disc 180 degrees since that would flip the two holes in the disc that are actually being used. I may have to give that a try.

For now, I just don't turn the petcock off and no leaks. But that means only your float valves are keeping the fuel from overfilling the carbs and running into the cylinders and possibly causing a hydro-lock on the next attempted start-up. That would be BAD! :surprise:

Thanks for the reply. I'll have to decide if I want to open her up!

Bob
If you leave the petcock on and it doesn't leak, why can't you put an inline valve after the petcock?
 

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Discussion Starter #5
If you leave the petcock on and it doesn't leak, why can't you put an inline valve after the petcock?
I could, and I've been looking for one. Only two places to put one:

1. Between the petcock and the fuel filter. That one would almost have to be a 90 degree angle valve to fit properly.

2. Between the fuel filter and the fuel pump. That's a really short piece of hose, only 3" long including what pushes onto the fittings at both ends, so probably only 2" of hose to work with.

If I could find something to fit in either of those two spots, that's what I would do for now. I kind of prefer finding a 90 degree valve that would mount in option #1 above. I've been looking, but so far no luck. Most of them too big or the wrong hose size.

I also wonder if a plastic petcock valve like you can get for lawn mowing equipment would be OK for this application or it it needs to be metal.

Hmmmm????? :?
 

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Maybe a vacuum-operated petcock valve from a 1500 could be made to fit somewhere?
 

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There's really no room to put any extra stuff in there. And when I was looking I didn't find any valves with the correct size fittings.

Mine did the same thing and leaked only when turned off. That's why I used the Teflon tape. I couldn't find an o-ring to fit the groove between the two halves. Flipping or turning the 4 hole seal won't stop your leak.
 

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Discussion Starter #8
... when I was looking I didn't find any valves with the correct size fittings.
Same here. I'm still looking right now and am finding nice 90 degree inline fuel valves, but only with 1/4" fittings on them. Like this one:

[ame]https://www.amazon.com/Shut-Off-Valve-Inline-Degree-Valves/dp/B0744FTDMW[/ame]

If I could find one of those with 3/8" fittings, I could splice that into the longer hose on the left side between the fuel petcock and the fuel filter.

Gonna keep looking. Also gonna stop at a local hardware dealer that specializes in commercial yard equipment, some big stuff too. Maybe I can find a fuel valve with 3/8" fittings there.

I'll let you know if I find anything that works.
 

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Discussion Starter #10
Don't waste time with that. I can walk you through the repair. Do you have a drill press?
OK, color me confused. I thought you said that flipping or rotating the 4-hole disc would not work to rebuild the petcock.

I have repaired several other Honda (riveted) petcocks before, but the rebuild kit parts (disc and two seals) were made to fit them.

I have used a hand drill in the past to drill out the holes where the rivets were and then tap the holes for small screws. If I need to, I'll buy a small drill press.

What else is involved in the "repair" of the '87 petcock? I appreciate the benefit of your experience on this!

Thanks.
 

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Pics would help, but.

The 4 hole seal is inside and stops gas from getting into the hose, right? There is also a seal between the two outer pieces of the housing. That one keeps the fuel inside the petcock.

It isn't like a normal o-ring as it has a square profile. Anyway, you can put a layer of tape in the groove before you put that seal in and it holds the seal out enough to keep the fuel inside the petcock.
 

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Discussion Starter #13
Found 'em.

First pic shows the difference in that seal size.
Third pic shows the o-ring seal that is leaking on yours.
Wow! That is a much bigger 4-hole disc for the '87.

If the seal in picture #3 is what keeps the fuel inside the petcock and mine is only leaking when in the OFF position, it makes no sense to me that the seal in picture #3 is the cause of that leak. It should leak whether it's ON or OFF if that seal leaks, correct?

What am I missing? :?

BTW, do you know the Honda part number for the bigger disc seal for the '87 petcock?

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Dennis,

Is there a ridge on the inside of the housing? It sort of looks like there is in picture #2. If there isn't a ridge you should be able to substitute a round o-ring (assuming you can find the right diameter).
 

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Can't explain it, but the housing must be slightly out of round and the seal/o-ring gets old and won't change shape as needed. That's a guess.

I wonder if that rubber rejuvenator Jim was using would help the rubber do its job again.

And they don't offer any parts. It was sold as a unit.

Wes, we looked high and low for an o-ring that would fit.
 

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Discussion Starter #16
Dennis,

Is there a ridge on the inside of the housing? It sort of looks like there is in picture #2. If there isn't a ridge you should be able to substitute a round o-ring (assuming you can find the right diameter).
Wes & Dennis,

Here's a thought! I've seen a lot of round profile rubber o-rings come out of a very old assembly that appear to have a flat or square profile.

What I think is really happening is that the o-ring WAS originally a standard round profile o-ring, but the rubber has taken a set and flattened out from being in its compressed location for so many years.

I'm really thinking that the original o-ring IS actually a round profile o-ring, which greatly improves the odds of finding one of the correct diameter and thickness to fit.

Yes? No? Maybe?

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