BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: chrisx1 on 03 May, 2024, 14:23

Title: Petrol tap thread
Post by: chrisx1 on 03 May, 2024, 14:23
Apologies if I have asked this before but what is the petrol tank thread size on a A65.
I want to purchase a couple of aftermarket fuel taps as I only have one tap fitted at the moment and I thought as everyone seems to have leaks with the original push pull ones, I would fit something else.
Title: Re: Petrol tap thread
Post by: chrisx1 on 03 May, 2024, 15:45
The thread seems to be 19tpi and dia is larger than 5/8” but smaller than 3/4” so about 17mm in new money. It must be a bpt I guess.
Title: Re: Petrol tap thread
Post by: iansoady on 03 May, 2024, 16:08
It'll be BSP (British Standard Pipe). Don't be confused by the nominal diameter which relates to the bore of the (gas) pipe it's intended for.  1/8 BSP has an overall diameter of about 3/8", 1/4 BSP has a diameter of just over 1/2". It's BSP parallel as opposed to BSP tapered which can sometimes be found.
Title: Re: Petrol tap thread
Post by: Allan G on 03 May, 2024, 22:17
It'll be 1/4 BSP or 3/8 BSP depending on which A65 tank it is. However if you buy 1/4 BSP taps (which are more common) and they are too small, B&Q sell adaptors in the plumbing section for 50p or a £1 a chuck, same thing as classic bike parts sellers are advertising at £5 or more each.
Title: Re: Petrol tap thread
Post by: chrisx1 on 06 May, 2024, 16:45
Thanks guys.
Title: Re: Petrol tap thread
Post by: Rob Neal on 06 May, 2024, 18:27
The taps I bought needed thread adaptors to fit the tank.  From memory it was 3/8 - 1/4 BSP parallel threads.  BSP being available in tapered form as well of course.  Don't bother with the usual bike spares suppliers.  Go to your local plumbing supplier and they sell nice brass ones and mine cost 79p each!