1986 interceptor 500 fuel petcock

All,

As mentioned in the title, I've got a 1986 interceptor 500. Like many others, it has a leaking petcock. However, it is leaking from the actuating piece (select fuel on, res, off) and therefore, I believe, is not rebuildable.

After reading all petcock threads, these are the things I've looked into:

1. The fuel-valve modification trick. I don't see how this would help my case.

Link: Daugherty Motorsports - Tank Valve Petcock Modification

2. A universal/identical petcock. Someone mentioned that they thought Pingel Enterprises has them, but I could not find anything of the sort on their website.

Link: PINGEL ENTERPRISE - Home of the worlds quickest motorcycle products!

According to BikeBandit, 84s and 85s have the same part number (3842836-001), but 86s have their own (7221407-001). Does anyone know if there is an equivalent part to the 86 petcock?

3. Used petcock. This is my second petcock and I got it used. Seeing that it has a defect, I don't know that I can rule out other used parts not being similarly defective. And, of course, the part is discontinued.

4. Making my own. Being an engineer, I can draw up and manufacture my own part, but that seems like too much work.

-----------------------

And now an unrelated question--does anyone swap newer engines into these things without too much difficulty?

Thanks,
Grant

 

As you have found, the 1986 model has a different petcock design vs. the '84 and '85 (this goes along with a different tank design). Also, the '86 is a gravity fed system from the get go vs. the fuel pump system on the '84 & '85 (as noted, Jamie D's site covers the '84/'85 modification to a gravity fed 'on-off' system).

I don't think you will find an aftermarket model that will work with the design of the fuel tank - I have looked into this as well. Perhaps 'three is a charm' on sourcing a used '86 petcock, from a running bike that is being parted out?

 

Well, it looks like to replace the o-rings I have to take off that actuating cover. This cover is held in place by what looks like interference-fit pins that have been peened over after the cover has been fit on. Maybe the solution is as simple as grinding or chiseling this peened part off, taking off the cover and cleaning/re-lubing everything, and pressing and peening some pins back in. Still seems like a good amount of work, though, and I have not seen anyone mention this as a viable option before.

 

Honestly, I don't foresee the solution being any easier than finding another assembly and hoping it works. However, I did find something that proved to be invaluable. I was having a hard time finding a Honda part number until I came across this website:

Service Honda - Honda Motorcycle Parts

Click Advanced OEM Parts Lookup and follow the directions. It will have you remote desktop to a Honda service computer with an extensive parts catalog on it. Maybe everyone already knows this. If so, oh well. If not, I am glad to contribute something.

The Honda part number for the 86 Interceptor 500 (VF500F) PETCOCK ASSY. is: 16950-MF2-884.

 

Service Honda and David Silver Spares (in the UK) are great sources for OEM and NOS (respectively) parts.

I think you may be ahead of the game if you can find a used '86 petcock vs. trying to rebuild one, though I would be curious to see if it could be done.

 

<<<<>>>>>

Go ahead..........just drill the rivet heads off and use small bolts after O-ring replacement.

 

All right, so here's what ended up happening.

1. I ground off the peened over portion of the pin holding the cover on.
2. Using a 3/32" drill bit I drilled all the way through the pins and petcock case.
3. I then used a 4-40 tap and tapped the previous hole VV(should have used a smaller bit--see attached drill/tap chart)VV
http://www.davehylands.com/Machinist/Charts/Tap-and-Drill-Guide.jpg
4. My o-ring was broken into two. Accordingly, I went out and bought a bunch of rings that looked of similar size. Nothing fit perfectly. At first I took a #20 o-ring and trimmed it down using a sharp blade. However, I got carried away at one point, took away too much rubber, and it leaked. Next try I used...a nail file, no joke. Using a nail file I filed it until it fit nice and snug.
5. I cleaned up everything and put it all back together using 1/2" 4-40 screws. Voila!

Uh, but now the motorcycle won't start. Hope that helps any future noob such as myself.

Another lesson learned was what outlet tubing to use. The petcock fuel outlet is a 1/2" id while the receiving line to pump is 1/4". Buy 1/4" line and flare it out using boiling water and something conical that you can open up the other side with. 1/2" tubing kinked real badly--go with 1/4" which doesn't kink so easily.

 

1985 VF500F petcock rebuilt

I did a rebuilt of one of my '85 petcocks. More or less as gman105 did, so I am following his numbering posting my comments from experience gained.

Here it is:

1. I used a 4mm drill to get the rivets' head off. The rivet itself is 4mm wide.



O-ring was cut, gave the whole petcock a clean with phosphoric acid (some POR15 product).

2. 3. I decided to keep the rivet as a guide so drilled with 2,5mm and tapped a M3 thread. I didn't want to risk drilling out so I went down to about 10mm at long side and 8mm at short side.



4. I used a 19mm x 1.8mm o-ring. It seems a very nice fit but I have not tried if it is leaking or not yet.

5. I used 2 stainless M3 bolts, the long one was 8mm long the short one was chopped to 6mm



Final assembly:





Side notes:

Used a 18mm x 2.5mm for strainer o-ring. Also seems a very nice fit, haven't tried if it is leaking.

I made a search for the 4-holed rubber. Original dimensions are 21mm diameter, 2.8mm thick.

Possible replacements are (Ebay seller responses for dimensions are in parentheses):

Honda Gold Wing GL1000 GL 1000 (approximately 13/16" x 1/8")
1973-77 Yamaha XS650 xs 650 TX650 (It's about 21mm across and about 3mm thick. )

 

I did similar to what blitzas did. In my case a previous owner had already taken it apart and rigged it back together and it was when it started leaking that's when I found out it wasn't supposed to be rebuildable and what threads there were where the rivets previously were was too weak for me to tighten down enough and not enough meat left to tap a different size. So what I did was hit my local hardware store and nabbed a couple of 8-32 x3/4 inch long set screws (standard thread NOT metric) along with nuts. The idea was that being I didn't have much metal to tap into, I used the 3/4 inch long set screws as studs which I pretty much force threaded in using red loctite to make sure it stayed put and then once all was in place I used the nuts to tighten it down. At the time I wasn't sure what 4 holed gasket to use so I used my old one, flipped it over so the worn side wasn't facing the control valve coating both sides with a thin coat of silicone grease, polished the face of the control valve that would be making contact with the 4 holed gasket using o-rings from an o-ring assortment I got from a hardware store. The only problem I had was with 1 of the 2 bolts that secure the petcock assembly to the tank. One of the set screw studs were getting in the way of 1 of the mounting bolts and wouldn't allow it to thread straight so I used a die grinder to grind the stud flush with the nut. However that still wasn't quite enough to allow the mounting bolt to thread straight and even if it could, there wasn't enough room between the nut and bolt to put a socket on the bolt to tighten it down. Off to the hardware store again for a stainless steel allen socket head cap screw. I had to chuck it up in a lathe to cut the dia down a bit on the cap to give me the clearance I needed for it to thread in straight. If you don't have access to a lathe then a bench grinder will work, it may not look as pretty but as using a lathe but it will work none the less and once the tank is installed, nobody is going to see it anyhow. At the same time I did the manual conversion using o-rings rather then hack up the original diaphragms and the end result is that I have a manual petcock that doesn't leak and functions perfectly though I'm sure I'll need to replace the 4 holed rubber gasket with a new one at some point.

 

Thanks for detailed post on rebuilding the stock petcock. It is very helpful to see the step-by-step in photos.

Please keep us updated on how everything works out.

On a side note, are you removing the vacuum diaphragm safety feature?

 

Glad if it was of any help.

I am not planning to remove the diaphragm, maybe I will also try gravity feed before taking any decision.

I will keep you updated. The plan is to make the installation along with the "'84 petcock on a '86 tank" conversion which will happen after the stripe and decals will be placed on the tank which is just painted.
It will take some time.

 

Keep in mind you still may have clearance issues when using an M3 screw. The button head of the screw that's nearest the petcock mounting bolt may stick out just far enough to interfere with getting that mounting bolt to thread straight and or not enough clearance between the 2 to place a socket on it on the mounting screw to tighten it down. The M3 screws the previous owner used on mine had 2 different styles of heads, 1 was a regular button head but the 1 nearest the mounting hole had a much shorter/flatter head. I at first disregarded this thinking the previous owner just used any old screw he could get his hands on to make it work but when I had clearance issues using a stud and nut, I realized why the previous owner used an M3 screw that had a shorter head.

 

Thank you for the clarification. Would you happen to have a sketch or a photo or two of the fix?

 

First off mines an 85 and I'm assuming the petcock mounting flange is the same on an 86. I don't have pics but if you do have a clearance issue with the M3 screw and the mounting bolt then you'll clearly understand what I'm referring to. You can check this before hand by simply placing the mounting screw in the flange after the petcock has been assembled and see if it drops in straight. If it does then see if the socket you'll be using to tighten that mounting bolt will fit over the head of that bolt without binding with the head of the M3 screw. I took a closer look at the old M3 screws from mine and it turns out the 1 with the shorter head is actually identical to the other except the previous owner shortened the head by grinding it shorter. Keep in mind that if you do have to grind the head of the M3 screw to gain the clearance you need, don't get too carried away with the grinder because the more you grind the head of the screw then the less area your phillips screw driver will have to bite into it to tighten it up. Another note is that the modified M3 screw on mine wasn't using a lock washer either and I imagine that was to allow more clearance as well.

 

I agree there might be a clearance issue as an M3 button head bolt + spring washer = 2.4mm + 0.7mm, which might be too much.
I could probably omit the spring washer and use a pan or truss headed going to less than 2mm.

I will try to fit the petcock in my tank #3 which is lying outside and update.

All above are for the '84 and '85 petcock.
The '86 is totally different using M8 (!) bolts and mounting plate is in 90 degrees angle to knob turning axis.

 

Here they are:



With button head screws, very limited clearance, I managed to tighten it (not really confident it was done properly) with an open ended spanner.



Changed bolts with pan headed and removed spring washers. Clearance was increased, I managed to tighten it (not really confident it was done properly either) with an open ended spanner.



Socket wrench doesn't fit, also tried my special, extra thin side, Chinese cheese-vanadium tool; still no luck.


Conclusion:

I'll leave the pan headed bolts, and by using a 6mm X 12mm allen screw for mounting the petcock there is also enough clearance!



There is no such issue with the '86 petcock!

 

A quick update:
I replaced the 19mm x 1.8mm o-ring I had previously used with an X-ring (also named "quad rings") #018 (18.77mm x 1.78mm).
I am quite confident this is the exact replacement of the original, being also an X-ring.

 

86 vf500f petcock woes

I embarked on rebuilding my petcock on my 86 VF500F today after reading your post. Do you have to stretch that x-ring somewhat to get it on the valve piece? My valve piece where the x-ring goes measures 32mm dia. The surface of the petcock where the x-ring rides once reinstalled measures 35mm dia. Just curious if the x-ring is the same size on 84-86 bikes and if the #18 (19mm) x-ring will stretch enough to work on my 86.

Thanks

 

The 84 85 is a lot smaller than the 86 petcock so I believe the aforementioned x-ring is a no go.
Better measure the dimensions of the original '86 x-ring, in my case original x-ring's dimensions were very close -to the first decimal- to the replacement .

 

Sorry to resurrect an old thread :cower: but since this forum is the de facto VF knowledge base as much as help on a case-by-case basis, I do it hoping that this info helps someone else in the future.

Went through the procedure on my 1986 VF500F the other day. After much hunting I managed to purchase what I believe is the exact x-ring Honda used on the petcock: 31,47 × 1,78mm. However, to my dismay it still leaked once put togeter. Somewhat reassuringly, it was more "a drop every few seconds" rather than "fuel gushing out of my petcock". Ended up replacing the x-ring with a 32 × 2mm o-ring and that took care of the problem. Has only been on the bike for a month or so but so far is holding up just fine.

The nice thing about the 1986 petcock is that there are no clearance issues for the new bolts (used 20mm M3s IIRC). If you go the tapping route (as opposed to nut), you may want to consider applying a drop of Loctite as you screw the plate bolts in since the thread is rather short and it being an M3 cannot be tightened all that much without risk of stripping.