Petrol tap

I have a ewarts  2 position tap that I bought thinking it was a Dommy one. Its now reconditioned  but has a straight thro supply so you would need to fit an elbow . I have  been convinced its a lightweight  tap , but not ever had a lightweight can't be 100% sure. I think the thread into the tank is 1/8 BSP  which appears to measure about 3/8" , Just as the 1/4BSP dommy thread measures about 1/2"   Most confusing  untill you realise that bsp sizes are related to the bore size that flows the liquid. 

I have previously owned a few lightweights and I think the type of tap you want is the Ewarts type shown in the pictures. This has a pull and twist action for the reserve. Sadly I don’t have this tap anymore as I sold it but hopefully it helps you when looking for one 

cheers

Simon

That thread certainly looks the same as mine. I do think a threaded pipe connection is more suitable though.  Going to look closely at some early road tests of lightweights as just about every restored /used bike has a different tap.

Alan,

I know it doesn't look like a leaky Ewarts tap, but this is available on fleaBay for £16.00.

Oh, and you will have to bend your fuel pipe upwards as it feeds from the bottom. I had one like this on my Honda 250 in 1972 and the downward facing outlet is real handy when refilling the petrol Optimus stove.

""Classic 1/8 BSP British Motorcycle Moped Fuel Tap Matchless & others Reserve NEW""

Peter

PS Same source found a tap with horizontal outlet. 1/8 BSP. Same price.

""Classic 1/8 BSP British Motorcycle Moped Fuel Tap with Reserve Horizontal Exit""

Thanks Peter, just ordered one. I also had looked before for a tap with a reserve but did not manage to find one. Much happier to have the reserve. Very useful ifo.

David

Hi Alan , after studying  many old photos I agree that Simon has the "correct "  style of tap in his pictures  for a 250 .   , not sure if the same applies for a 350 .    My tap has the same  correct main and reserve action but will need an elbow at the bottom  to give a horizontal outlet towards the engine.. If you want it I could swap it for an electrical gismo from your stock!!.

I have not found reserve taps (unmodified)  to be  very effective.   Usually only enough fuel left for a couple of miles .  The ewarts one  also allowed a very slow seepage from the reserve  to the main  function so a very economical bike could actually continue running  till the fuel ran out without you being aware  although some symptoms of weak mixture were apparent.

For Al Osborne, I’ve got this available if you still want an ewarts tap with reserve.  Bought it a few years ago but now realise I’ll never fit it to my Jubilee, the horizontal outlet would foul my under tank keyswitch.  Any use to you?

Bruce

That does look to be the gen article,  If the plunger is not pretty tight  you  are better off renewing  the cork . Don't bother looking for a new plunger . I bought  a box full of them and even unused they still need new corks.

I bought the one that Peter found on eBay and was surprised when the lever fell off. it was not fixed onto the spindle. You might say it is some security for a bike that doesn't have any otherwise.

David 

Hi Ulrich,   Sounds like you have realised that the plunger can be reassembled in different ways, and only one is correct!.   I can probably take a photo on my phone and get it sent to your phone if you PM me the no.   Anything else is too IT for me.   If all else fails i can give you a spare plunger, As you have no doubt found out this extended plunger is not availiable , probably my fault as i bought up any that came up.

Hello Alan,

thanks for the pic of the plunger.

That´s what I was looking for.

@Robert:PM sent.

Hi Ulrich,  The picture of plunger in Alans post shows the forked brass end fitted 180 degrees out compared to my NOS ones . Done it myself when fitting new corks. The corks need to be a very tight fit as they soon loosen up . I buy a bag of corks and size then using a micrometer , I soak corks in warm water and coat with some bar soap  Seems to help. Dont lose the tiny screw as they are more complicated than they look. Plunger taps have a habbit of turning themselves off with vibration so I pull and slightly turn. Its possible that the difference in the parts arrangement could be to do with the horizontal outlet, mine is vertical.  

Here are the components of my tap minus the cork:

I can spot two marks on the rear part of the plunger, they line up with the two holes coming from the inlet.

There is a brass sleeve in the rear end of the tap with one hole ( reserve?) and the front hole is in front of that sleeve where the cork sits.

So the plunger would go in like this:

Is this a worthy subject for the club Parts Commissioning scheme? I'd happily add my name to the I want one list.....

While we are talking taps, the Ewarts tap cannot normally be dismantled, as the plunger is riveted together. However, new corks are available - I've seen them for sale at times - and if you get one, its an easy process to replace the old cork, without undoing the plunger:

1) Just remove the old crusty cork with a sharp knife

2) Boil your kettle and dangle the new cork in the steam for a minute

3) The cork will become pliable. Cut it neatly with a very sharp craft knife or scalpel, lengthways. into the hole in the centre, so that it opens out.

4) Feed the cork onto the plunger and insert the plunger back into the tap housing as soon as.

5) Because the cut was clean, the tap will seal.

Job Done

Hi Andy,  I will try that next time,  I have always put the Knob in a small vice and punched the shaft out with a thin steel punch . Reversing the process  on assembly and spreading the end of shaft out slightly into the knob reccess. . I have a couple of spare taps serviced and ready to swap as needed.They usually last for a few years depending on the quality of the cork. I dont know how they will last if E10  becomes the norm.

One final  comment for the saga. The main enemy of corks is tank rust. The tiny particles are very abraisive and wear out the cork , worth flushimg the tank out whenever it comes off.  

Thanks to Alan and Robert I  now can assemble my petrol tap correctly.

Thank your for the help!

Nooooooo !    what can we talk about now ?.

that will be  20/50  fully synthetic then , !!.