14mm nut for gas tank

[Reign]

Does anyone know the exact size of the threads on the gas tank? I tried a M14 x 1.5 and it's too coarse. I'm thinking it's M14 x 1.0 but my local hardware stores don't carry that size. I hear it's a really uncommon size, and hard to find even online.

[90GTVert]

I could never find anything in the hardware stores here that works. Are you trying to bypass the vacuum petcock? If so...

49ccscoot.proboards.com/index.cgi?board=fuel&action=display&thread=1355

[jmkjr72]

if you are talking about a tap it should be some metric pipe thread

the possible down side if you go with sae brass is that that may be the only time you are able to use that fitting getting it in the metric threads may fubar it enough that if you ever take it out you will need a new one

[90GTVert]

I used the die as described in the link above. It actually creates nice threads. I have not removed the fitting (not really sure why you'd need to) but from seeing the threads created I don't think it would be an issue.

[jmkjr72]

i missed the die part wow im suprised there is engouhe material there to rethread it from metric to sae

[Fox]

This thing might fit:

www.partsforscooters.com/Fuel_coupler_50cc-2?sc=9&category=109661

[Reign]

Got it all done while I was waiting for replies

I had a spare petcock sitting around, so I took a hacksaw to the piece with the nut attached, then drilled out the remaining pieces of the petcock that was still attached to the nut


Then I took a nut and screwed it onto the NPT thread, and soldered the two together so theres no leaks. I soldered both edges, and then filed the edges down so they're flat-ish




The plan was to solder the nut from the petcock to the nut that's holding the NPT


Then I actually got to work on soldering the two together


And after some filing, the finished product


And here's what it looks like hooked up to the tank!

[Fox]

McGYVER! Great job on that.

[tomcas]

If you want to know the pitch of the thread then either measure the distance from correspond points or match the threads from a metric bolt with a known pitch. The diameter of the bolt you use is unimportant, just that the threads mess when held side by side. One simple trick is to count down 10 threads, measure the distance between coresponding points on the tread form, then divide that distance by 10.

[dr1445]

regarding the 14mm nut set up, in the base of the petcock is an oring that seals against the tank spigot.. those 14mm threads are not designed to seal. you may want to check it doesn't weep fuel..

[Reign]

Apr 11, 2011 5:03:08 GMT -5 dr1445 said:

regarding the 14mm nut set up, in the base of the petcock is an oring that seals against the tank spigot.. those 14mm threads are not designed to seal. you may want to check it doesn't weep fuel..

It does leak right now. I tested it to make sure it wouldn't, but it does. I'm going to head out today and buy some yellow Teflon tape to wrap around the threads today, and then it should be set.

[dr1445]

i recall from experience many years ago that the white teflon tape was not fuel resistance, but i could be wrong.. you might want to soak some of that yellow tape in a small jar with gas and see how it holds up, before you button it all up..

[Reign]

You're right. White Teflon tape breaks apart in gasoline. Yellow Teflon tape specifically says "For use with: Gasoline, Petroleum oil, etc. etc"

[dr1445]

thanks for lifting the cloud of ignorance, i did not know about the yellow tape..

[Reign]

Apr 11, 2011 14:13:26 GMT -5 dr1445 said:

thanks for lifting the cloud of ignorance, i did not know about the yellow tape..

I didn't even know the yellow stuff existed until last night when I was searching whether Teflon tape worked with gasoline.