Drain plug size

  Hi guys, can someone has the measure of the adapter for the Drain bowl plug of VM 28 carb?!  I want to find something in the plumber shop ..
thank youu

IIRC they should be M6 with a .75 pitch

As good4 says m6 0.75 pitch, i made my own adaptors and drain screws in brass.

I have found 1/4 brass fitting.. m6 and 1/4 are similar I guess ?

Similar size but completely different threads.  Don't mix them!

For VM carbs, you don't need fancy adapters.  Get some cheap pieces of clear tubing, and pencil point grind them on one end.  Screw the tube into the threads as hard as you can, and they won't leak enough to matter.

I found that the thread is the same size as used in Presta bicycle tube valves.



Show is a mountain bike inner tube valve screwed into a VM24 float bowl. Cut and grind the rubber off, then you can easily unscrew the sealing guts and discard them, then shove a clear hose over the thread.

They throw old tubes out at bicycle shops, they don't patch them. You can usually find them in the trash outside bicycle shops or just go in and ask them if you can take one from the garbage

You have to specify "Presta" valve tube.

Thank youuu, I bought from Waltmart Canada 2 m6 hose fittings for 10$

Yup ! They are M6 .75 mm ( hard to find)  Amazon has M6 but are coarse tread or non metric and wont fit my Mikuni 26 ! 
I was lucky to find a pencil tip that work, but I want to check all 4 carbs at ounce.
So...I'm waiting for Amazon to get a set of plastic M6 ?? At least, I wont damage the treads.   

Maxbou92....Did you found any ?

Sorry to hear that your amazon m6 haven’t fit. I don’t have receive it yet!! I hope they will fit !!
 

Maxbou92 wrote:

Sorry to hear that your amazon m6 haven’t fit. I don’t have receive it yet!! I hope they will fit !!

 

The thread for the drain screw is 6mm x 0.75mm fine thread.
Those in the pic ( 6 x 1 ) are 1mm pitch so are too coarse and won't fit.