A A A A Author Topic: Rebuilding the 500/650 Euro Fuel Tank Petcock  (Read 2474 times)


Rebuilding the 500/650 Euro Fuel Tank Petcock
« Started on: 18-Sep-07, 17:45 »
From the old MSN Website by TurboTim

(I tried to list as "petco*k" in subject, and here too, but it kept automatically changing to petrooster, I subsequenlty changed it to "Petrol tap" so at least it made sense) ;) Seagrass  ((Fixed and edited!! - I changed the word censorship setting to check whole words only))   2smiley Kathy

The first step is to drill out the two rivets holding the cover plate to the body (5mm drill works well). Rather than take them back flush to the surface of the body, I left mine flush with the cover plate. This left enough material to act as locator pins when I put it back together.

Gently pry the cover away, taking care not to distort it. When this has been removed, you can take out the tap and two washers. This will expose the rubber seal. Take note of which side is facing you, because we need to flip it over when we re-assemble the petcock.

If your O-ring is beyond repair (and not available from Honda anymore), a fellow  suggested that the O-ring from a 73 CB750 works- it's part no. 16955-268-020. It looks a little smaller diameter and slightly thicker, but when it's all together works. Thanks Mike :)

Drill the pilot hole for the new screws that will hold the plate on when we've finished. I used a 2.5 mm drill that would tap a 3 mm thread for the screws I had. If you have a drill press, fine, but I did mine with a hand drill, making sure I had the bit perpendicular to the work-piece.

Tap the thread in the pilot holes.

Give the two washers a good clean. I used some 0000 steel wool on the metal 'wave' washer.

Give the underside of the tap a polish to make sure the contact surface is a smooth as you can make it. I had some 1500 grade wet and dry I placed on a sheet of 6mm glass I had lying around to give me a flat surface

Re-assemble the petcock by placing the rubber seal back in, taking care to reverse it.

Sit the tap on top of it, in the 'on' position

Work the wave washer over the tap

Next then the fibre/nylon washer.

Place the cover plate back on, making sure the 'on' position is at the top. You might need to 'click' it in to place if you're using the 'locating pin' system I've done. Screw the cover plate on with your shiny new 3x12mm stainless steel screws, or whatever you have handy that will fit. You may need to reduce the height of one of the screw heads to allow the tap to turn fully

You may need to find a new O-ring to seal the fuel tap against the fuel tank when re-attaching the fuel tap to the tank.


Re: Rebuilding the 500/650 Euro Fuel Tank Petcock
« Reply #1 on: 18-Sep-07, 20:02 »
Hi Seagrass,

I've attached some other information I found about rebuilding a petcock that may also be of use (it even has pics!!)  2smiley

Rebuilding the Fuel Petcock


PS:  I have copied this PDF file to my Gallery so that it can also be accessed there.


Re: Rebuilding the 500/650 Euro Fuel Tank Petcock
« Reply #2 on: 18-Sep-07, 21:48 »
Thanks Kathy.

As I think of obscure items I have seen elsewhere, I try to post them on the relevant sections of this site so we all have easy access to them. This was a job I just completed on one of my Euro's so I thought it was worth posting it.

P.S. This was a very easy task to complete (would have been much harder without the good instructions)



Re: Rebuilding the 500/650 Euro Fuel Tank Petcock
« Reply #3 on: 19-Sep-07, 10:51 »
what if we had a section dedicated for these types of things,ie: tap rebuilds, brake re builds etc.



Re: Rebuilding the 500/650 Euro Fuel Tank Petcock
« Reply #4 on: 19-Sep-07, 15:57 »
mAL...THEY'RE called "stickys"  on other boards and I think theyre on here too somewhere

Sidecar Bob

Re: Rebuilding the 500/650 Euro Fuel Tank Petcock
« Reply #5 on: 26-Apr-08, 09:38 »
Since Kathy posted a link to a description of how to do this some years ago I have done this several times.

The petrooster (I think that term should stick) on my 650 needed a new o-ring so I looked in my assortment and found that the only one with suitable cross section was too small diameter. I stretched it over hte handle part and it went in but it was incredibly stiff so I took it out again and lubricated it with a bit of silicone brake grease. 2 years later it is still easy to turn and still does not leak.

Sometimes the seal is too hard to work there is a possible replacement available. I bought a GL1000 Master Carb Overhaul Kit from Randakk. This kit is very complete and even includes a petcock rebuild kit and a fuel filter. The seal in Randakk's GL1000/1100 petcock rebuild kit (http://www.randakks.com/Carb%20Parts.htm#5) has this part. The kit also includes 2 fuel seals that would not be necessary for transverse twin petcocks. I will ask about purchasing just the seal when I contact him about a kit for my 650's carbs in a few weeks.

Retro Rider

Re: Rebuilding the 500/650 Euro Fuel Tank Petcock
« Reply #6 on: 13-Oct-21, 01:09 »
Does anyone know the o ring size between the tank and petcock ?

Sidecar Bob

Re: Rebuilding the 500/650 Euro Fuel Tank Petcock
« Reply #7 on: 13-Oct-21, 02:05 »
Wow, this is an old thread. I don't know the o-ring size off hand (I bought a cheap o-ring assortment so I picked one that fit and didn't pay attention to which size it was).

Since this has been re-opened I should mention that since I last posted in this thread I have learned that the internal seal for the petcock is called a "wafer" and after a bunch of experiments with various wafers (including the one Randakk sent me to experiment with) I eventually gave up on restoring my original petcock and bought one of the many suitable non-vacuum ones from eBay.


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