Leaky Petrol Tap

hi guys,

I posted a note earlier but put it on the "hello" channel???

my petrol tap leaks from the filter bowl at the bottom of the unit. it needs a new "special washer" which from the main dealers works out to be about £20.00 ?
I used a thin fibre washer and a bit of gasket cement to try and seal the threads between the threaded parts with some success but it will need attention - damn weep ! ( the bike not me - yet)

other members must have had this problem any ideas ? Too much brute force and i will end up looking for a replacement tap.

PS I have run out of PTFE tape but that will be the next ploy.

I am not off the road but it does need sorting.

Cheers

Steve  

Try an O ring 19mm OD x 2mm dia thickness

hi john

Like many of us I have a box full of O rings which I did try but I will look closer. I am a bit worried that the threads will go on the screw in plug. You can feel them just starting to slip when you tighten down. Possibly a bit of PTFE tape will help and enable the O ring to seal better.
Anyway I will look for a 19mm OD O ring as you suggested.

Bike is going well and I have found another CDI unit as a spare which works well so I am happy on that score.

May be a good idea to get on the lathe and turn up a aluminium plug

Hi JW

Not a bad idea - the plastic ones obviously have a limited life.


I notice on ebay a flurry of Townmate sales , some nice looking ones.

Cheers

Steve

steve9e what exactly is the petrol tap?

Is it something in the following chart?

hi Duckrider

Item 15 on the diagram - a Japanese energy saving device ? It saves the rider the physical effort of switching Off an On the petrol supply to the carb - big deal and must have cost a fortune against a simple petrol tap. It probably has more parts in it than the engine?

Anyway mine is up an running again and I feel much better now , knowing I do not have to physically operate a tap..

Ride on

steve  

sorry Duckrider , the whole assembly is item12, item 15 is another little devil that can leak.

Steve

One tip I can give you is not to replace it with Chinese production.

I bought a while ago one ROC for 10 euros and within 10 days the inner membrane overwrapped and rolled like a handy quality rubber melting from the gasoline.
So the leaks started again.

Because the new one is very expensive I bought a used from a local store, but first I agreed that if it did not work properly ι would return it and I would get my money back.

Maybe I still have a few parts of this spare part in the basement, I'll take a look and tell you what he uses as oring.

You want the No12 or the No15?

hi Duckrider

fortunately I found a used item which worked fine and I have "overhauled" my original one.

the original one had 2 problems ;
1.0 the seal washer on the filter bowl disintergrated when I removed the plastic bottom part to check if the filter was clean. A 19 mm OD "o" ring sorted that but the threads on the plastic unit were not good however a bit of PTFE tape solved that.

2.0 it leaked from the rubber diaphram down to the fixing screws and into the wide world. I checked the rubber membrane which showed signs of petrol attack but there also was sediment on part of the sealing surface in the centre, so I cleaned that, checked that the vacuum valve worked freely and re assembled it using a small quantity of liquid sealant and screwed it all back together. It seems to work OK but it now resides in my spares box.

Like I said earlier it is a lot of bother for a simple task. Similar valves were used on bigger bikes as well in the 70 -80's. I bet a lot of runners have had them removed now?

If you have solved the problem with a used one you are lucky, I needed three attempts



Here on the left I show you the Chinese version:



and here the Chinese membrane after two weeks of use, and two gaskets I built trying to repair mine:



The gasket is 19x2 mm and inside diameter 13mm

The difference between original gasket and Chinese is that the second has a wire filter integrated, and the cap bolt is steal.





At one of the used parts i found this problem :



Any way, you are now ok with this problem.

Οne of the used parts i bought was permanently closed, the second had a cut flange and the third was permanently open.
My own was leaking from the membranes.
So I tried all possible damages.

If i wiill have any problems in the future I will put a small electric fuel valve that will be activated by opening the key switch and will be placed in the space below the tank next to the battery.

I will leave the old system just to look like original, but it will not have any effect.

Hi Duckrider

I know it is nice to retain an original part but with having the leg shield covering all the pipe work, I think if I get the same problem in the future I will fit an inline fuel filter in the pipeline from the tank, into a manual fuel tap and just seal the manifold connection. It is very simple and pretty fool proof and can be returned to the original system easily.
Using an electrical fuel tap is OK but it is just another source of future problems.
My other bikes are older and all have manual fuel taps so I do not see much of a problem, infact you could argue that it is an improvement. My T80 is a "hobby bike" not a commuter so I am more interested in the riding experience. Since I got my bike back on the road about 5 weeks ago I have done about 400 miles and in the meantime I have replaced the rear crown wheel set, CDI unit and the fuel tap. All these problems were due to the bike being off the road since 1992 I quess , and no doubt lack of lubrication etc. in it's early days:D

cheers

Steve

Good point there Steve, no point in complicating matters with electrically operated taps. A good quality manual fuel tap could easily be fitted in place of the original, and as you say only see the operating lever can only be seen through the hole in the leg shield so no one would notice. At least with a manual tap the fuel supply can be cut off, if the diaphragm in original tap fails, fuel can leak and cause a fire hazard, not only your T80 going up in flames, but your garage or shed as well.

As i say , simple lives for ever.

I accept the installation of a simple mechanical fuel valve as the ideal solution.

But this valve should be branded to be trustworthy.

Some after market is not reliable, cheap but not reliable in time.

The valve to be mounted should be able to be properly supported and no part of the plastic leg shield should be removed.

Do you have one in mind we can put it on to our bike?

Sadly these poor quality 'fake' petrol taps are typical of some of the crap Chinese (and other far east countries) parts that are coming into the classic bike and car replacement parts market. In the UK its a major problem particularly with car parts some even in boxes with origial manufacturers names like Lucas
As for a replacement tap, something like this should suit, it would need a mounting bracket attaching https://www.ebay.co.uk/itm/6mm-1-4-Metal-Inline-In-Line-Petrol-Fuel-Tap-On-Off-Fits-Many-Lawnmower-Engine/332367505633?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D2%26asc%3D49138%26meid%3Ded69841c94d64d90b50f31249695e245%26pid%3D100005%26rk%3D2%26rkt%3D12%26sd%3D192209414409%26itm%3D332367505633&_trksid=p2047675.c100005.m1851

or this one that has a fixing hole to mount it on a bracket https://www.ebay.co.uk/itm/6mm-1-4-Metal-Inline-In-Line-Petrol-Fuel-Tap-On-Off-Fits-Some-BRIGGS-Models/253754049707?hash=item3b14eb84ab:g:gxIAAOSwImRYNWsW

These replacement taps are just ON an OFF, as some of them have a third position for RES.

Very good idea and very cheap.

Νow the only we have to do is  to solve the  mounting problem.

Maybe dismantling the old one and keeping the part of the original switch that is secured with the screw and on it we place the new one.

Duckrider wrote:These replacement taps are just ON an OFF, as some of them have a third position for RES.

Very good idea and very cheap.

Νow the only we have to do is  to solve the  mounting problem.

Maybe dismantling  the old one and  keeping the   part of the original switch that is secured with the screw and on it we place the new one.

Just needs an L shape bracket making, simple home workshop job hacksaw, file and drill