Long story short, my NC21 tank developed a leak. I removed the tap to stick some sealant in there and didn't notice an O-ring or anything else there.

On reassembly the joint leaked. A lot.

I've tried:
- O-rings. Lots of them. The ones that last the longest are very thin but they all seems to expand over a couple of days and leak again.
- Instant gasket - with and without o-rings in situ
- Speaking to David Silvers who sent me a copy of the micro-fiche but claim there shouldn't be an o-ring there
- A homemade cardboard gasket. Holding as of one hour in but who knows how long for?

My question is - should there be an O-ring? If DS say there shouldn't (and I'm crap at reading micro-fiche) then what the hell do I do next? Really tearing my hair out here...

TIA

You could try proper gasket paper, maybe covered in a proper petrol resistant sealant.

Druid

Take a look at the exploded diagram of the petrol tap, if you have all the parts there and they are in good condition the tap isnt' tightened up enough.

Isn't part 6 an O-ring?

Druid

MINE did this!! Stripped it to sort out the holed diaphragm, reassembled it - petrol leak.... stripped and rebuilt - still leaking??!!

Closer inspection revealed an o-ring groove in one of the half's, not having any spare o-rings I cut out an "O" 2-3mm wide out of an old thick inner tube and fitted this in its place.

Job done.

Still no probs.... heres a photo of the groove I took in case I had to get another o-ring:

http://i109.photobucket.com/albums/n61/ ... C02068.jpg" onclick="window.open(this.href);return false;

(I take photos of everything when working, I have the memory span of a small forgetful fish... )

Now if thats not an O-ring groove then I am a albatross.... checked my immediate working area - no o-ring to be found?? If yours didnt have one either then that makes me feel a little better, lol

In hindsight it didnt seal because I had a small metal ruler across the join... :D Dont look at the pic for too long of you will get a headache...

P.s have contacted Dave Silver about a rep. o ring & diaphragm - you have to buy the COMPLETE fuel tap, out of stock at the mo, £79....

Hmm, they lie! :D

That o-ring is used on many many honda bikes.

o-ring is listed there in the pic part # 16958-MF2-880 approx. £1.50 or if you believe that microfiche and 1987 prices, 70p...

email dave silvers and ask them to order the above part # for you. Some superglue should repair the diaphgram, did it to a mates about 7 years ago, still fine now.

Similar thread Here @ CBRXX

To Highlight what has been said about the o-ring in that thread if you dont' wish to read..

The o ring you need to replace seals the fuel tap housing to the tank. The diaghphram will be ok dont dismantle that. the part number on ron eyeers m/site for bb is : ( 5 ) 16958-MF2-880 O-RING

Ron Ayers Motorsports - Discount Motorcycle Parts

that should make it clear.

Easiest way to empty tank is ot siphon fuel into a container. I use a clear plastic hose that way you can see the fuel coming when you suck on it to avoid getting a mouthful. Works most of the time. By the way E10 fuel taste sweet.

When you go to reasemble stick the filter in tap first then slide o ring over filter and seat onto tap. Filter holds it in place. Also have tank rightway up and put tap in up from bottom. This ensures filter and O ring stay where you want them to be.


Of course Ron Ayers are US, they'll ship to the UK ($2.50) for that O-ring, but it's prob quicker / cheaper to get one off silvers :)

No :O: ring in mine either, I just used blue hylomar, never leaked since. :)

the o ring is tiiiny

I took mine apart to flush out the tank whilst I stripped and rebuilt the carbs y.day



If you take a gander at that (ignore the rust! >.<) you'll see the recess in the tank, thats where the o-ring sits.

If you remove the strainer from the tank and put it back on the petrol tap the o-ring goes over the enlarged end that you can see in the pic, if you look closely you can see theres no rust on the tip of the strainer where the o-ring sits. it's easier putting the straner on the petrol tap and putting it back in, it helps keep it in place.

Mine was missing between the two halves of the tap where the diaphragm fits?

Just surprised it didnt leak before to be honest??