Fuel tank problem

chrisf1

Joined
Aug 23, 2015
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Hi again everyone I have a problem with my tank leaking fuel from the tank to tap fitting, I have fitted dowty washers 3 times and they can't all be faulty, I have tried a flat washer under the dowty to pull it up evenly and have just ordered some 1/4 BSP fibre washers to give the old fashioned way a try but up to now I cannot stop it dripping and the garage is full of fumes every time I open the door I have tried holding the tap while I tighten the lock nut and have now stripped the thread on the tap, so have also ordered a new tap so can anyone give me a suggestion for some kind of petrol proof lagging such as the sort of stuff gas fitters used to use around gas pipe threads to seal the joints or any other suggestions I could try, many thanks Chris
 
chrisf1 said:
I have fitted dowty washers 3 times and they can't all be faulty,
Click to expand...

It's probably not a matter of them being faulty but because normal Dowty washers aren't designed to seal the screw thread so fuel can leak past the Dowty seal along the thread.

Fuel tank problem
Fuel tank problem
 
Cut and pasted from CNW site
I do not use a sealing washer with these. Just several layers of Teflon pipe tape
 
I prefer to use copper/rubber crush washers.
The bonded rubber is forced into tight contact with the thread as the outer copper ring is compressed and requires a flat washer between it and the nut.

Carburation/Fuel :: Fuel Taps and Parts :: Tap Parts :: 1/4" BSP Tap Parts :: Crush Copper/Rubber Washers for Fuel Tap 1/4"

Crush Copper/Rubber Washers for Fuel Tap 1/4" Sealing washer for 1/4" petrol tap - Price for ONE washer. OEM: 70-7351, E7351 Rubber seal encased in copper, when fitted to fuel tap and screwed into tank, the washer crushes effecting a good seal. Hole id 1/
www.feked.com www.feked.com
Fuel tank problem
 
Thanks everyone for your knowledgable help I have loctite and a new tap on order so have to wait arrival one other thing while here should the reserve tap be on the left or right side of the tank while sitting on bike thanks Chris
 
chrisf1 said:
one other thing while here should the reserve tap be on the left or right side of the tank while sitting on bike
Click to expand...
Pre-850 Mk3 the reserve was on the right-hand side...
Fuel tank problem

...but you can fit the main and reserve either way to suit your own preference (some owners prefer to fit two reserves so no fuel ends up trapped on the main tap side of the tank tunnel).
 
I have found that the best sealing washers are not Dowty but Statoseal. These are what Triumph & others used.

Martyn.
 
I have had a weeping fuel tap problem. I used plumbers teflon tape on the threads and a Doughty washer. No joy. The tape just turned to goo. I just ordered some Locktite 567. Out damned spot! I’m guessing that the Doughty washer doesn’t do anything but take up space in this application?
 
I am about to drain my tank and replace a defective fuel petcock that is worn out.
I though to use Permatex Hi Tack on the petcock threads (sparingly) before I screw it in.
I thought that the advantage might be that it does not harden like thread sealant, so
can be tightened a bit later if needed.
Love to get all your thoughts
Dennis
 
DennisMo said:
I am about to drain my tank and replace a defective fuel petcock that is worn out.
I though to use Permatex Hi Tack on the petcock threads (sparingly) before I screw it in.
I thought that the advantage might be that it does not harden like thread sealant, so
can be tightened a bit later if needed.
Love to get all your thoughts
Dennis
Click to expand...
Hi Dennis. High tack is used to "glue" gaskets temporarily . When I worked for a Detroit Diesel rebuilding Shop, we used it exclusively.No other product was recommended at the time bye DD. Not sure it will help seal your leaky petcock.
 
This is a great thread Sealer. It worked for me in a spot where the loctite failed.
Stays soft.

I have some rubberized washers that look like a Dowty washer but are made just a bit differently. They will seal the threads on a gas tap nicely without any thread sealer.
Usually I add the thread Sealer just as insurance against leakage.

Glen
 
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