Petrol tap gauze filter THREAD

[Roderick]

I have inherited a push-pull petrol tap and a gauze filter to fit to it but the filter has no thread in it at the moment to screw the filter into it & so I will have to tap the filter first fitting.
The thread on the filter is 1/4 x 40TPI as best I can measure. Is this 1/4 x 40TPI ME (Model Engineers) thread or something else altogether?

Rod

[Andy51]

Unless someone has changed the thread, it won't be ME. If it is of UK origin it would be BSP thread but the dimensions you quote don't match any of the BSP ones.

[clive]

I thought the filter on a petrol tap was usually soldered on when fitted. Or have I got the wrong idea? Are you talking about a thread to attach the filter to the tap? Sounds as though the filter may be from a model rather than a motorcycle.

[Roderick]

Yes, it is the thread on the filter, not the thread on the petrol tap that screws into the petrol tank boss (1/8 BSP).

I think I have seen both soldered and screwed in filters versions over the years. I bought the tap (newly made but no filter) & and the filter (newly made with thread) off a motorcycle jumble stall years ago. Both were, I assume, pattern items. At the time taps with filters didn't seem to be available so I lumbered myself with it. I wouldn't want to use a petrol tap without a filter.

The only 1/4" O.D. x 40 TPI thread I can find reference to is 1/4 M.E. (Mechanical Engineering).

Roger

[Andy G]

20220724_094432.jpg

A phot might help here...looks like this?

Or this?

[SPRIDDLER]

I use one of these as any muck is easily seen without having to disturb the tap or drain the tank or disconnect the fuel pipe............

Filter. Petrol inline.JPG

[Roderick]

I used to use these filters on the old BMW airhead until an authority at Motorworks advised that they cause problems, on that make at least. They may be meant for use with a petrol pump without which the thro'-flow maybe is limited. Might not matter on a thrifty single cylinder engine. Anyway, I have given up using them & instead ensure that the flexible rubber pipe from the petrol tank is a long one which loops well low under the carb. Dirt drops out of the light weight petrol medium in the bottom of the loop which I check periodically & clean out as necessary.

Thanks for the photo, Andy.

Rod