Threads after plating

[alexd912]

Hi there,

So it seems that it is one step forward and 5 back at the moment.

My tank was chromed a year back or so and after the pre plating of copper I think it basically lost the threads where the fuel and oil lines go.

Any idea on the thread sizes as I will need to re-tap them out.

Here are the pics of the effected unions.

Not sure but the stainless looking one (the larger) seems to be 0.1 tpi. Not sure imperial size as i dont have thread checker.

Alex

[Doug]

Alex,

The large fine thread on the standpipe is 3/4. The pitch is difficult to get a good reading from as the thread length is so short (my fitting is even shorter than yours), but seems the best match is to a 26tpi gauge.

-Doug

[alexd912]

Hi there doug,

Thanks and I will try and buy a tap of eBay.

The fuel tap thread has now been done as this seems to be standard on old British bikes.

The smaller ones I still don't have taps for.

Br Alex

[alexd912]

HI there,

I have managed to find a tap for the larger 3/4 and I hope its correct.

Now Im having real difficulty to find the correct tap for the brass fitting. its 1/2" to 7/16 and I need the 7/16 tap. Only issue is that it seems to be impossible to find a 7/16 19 tip or it could be 18 tip BSP tap.

I have trawled the internet with no luck. To me this seems a standard fitting.

Does anyone have any idea? Are these fitted to any other pre war Dougie?

Br

Alex