Those of us who have fitted VM34 carbs will know that the drain plug is large so the main jet can be changed without removing the carb, but when you want to drain the float bowl say for winter prep, then it can get a bit messy and smelly.
I know some folk have found a way to introduce a drain screw, but this is how I did it.
The thread size is M16 x 1.0 and the ID is about 12mm at its widest (it has a bit of a taper). The 'nut' end is 2mm thick so a bit thin for drilling and tapping ... I decided on something bespoke. I'd accidentally come across brake caliper bleed nipple repair inserts when searching FleaBay for something else, perfect for attaching a drain tube to. They have an M10 x 1.0 thread.
I had a bit of 12mm ID tubing left over from making my front engine mount cross braces and got someone to turn it down so the OD is 15.9mm. I could then cut the M16.1.0 thread. The flanges would simply be half-thickness locknuts Loctited in place. I tapped the tube for M14 x 1.5 to M10 x 1.0 thread reducers avoiding tapping where the M16 thread was cut as I figured there wasn't enough metal!
Belt and braces .... I bought a short length of 7/8" (happens to be almost exactly 15.9mm) round aluminium bar and drilled/tapped etc similarly and this makes for a shorter assembly.
And here's the end result. I found a couple of O rings that fitted nicely and just screwed the new plugs in finger tight. I'm rather pleased with the end result
Hopefully someone will find this helpful, and if there's an alternative method then please share it here!
Cliff
I know some folk have found a way to introduce a drain screw, but this is how I did it.
The thread size is M16 x 1.0 and the ID is about 12mm at its widest (it has a bit of a taper). The 'nut' end is 2mm thick so a bit thin for drilling and tapping ... I decided on something bespoke. I'd accidentally come across brake caliper bleed nipple repair inserts when searching FleaBay for something else, perfect for attaching a drain tube to. They have an M10 x 1.0 thread.
I had a bit of 12mm ID tubing left over from making my front engine mount cross braces and got someone to turn it down so the OD is 15.9mm. I could then cut the M16.1.0 thread. The flanges would simply be half-thickness locknuts Loctited in place. I tapped the tube for M14 x 1.5 to M10 x 1.0 thread reducers avoiding tapping where the M16 thread was cut as I figured there wasn't enough metal!
Belt and braces .... I bought a short length of 7/8" (happens to be almost exactly 15.9mm) round aluminium bar and drilled/tapped etc similarly and this makes for a shorter assembly.
And here's the end result. I found a couple of O rings that fitted nicely and just screwed the new plugs in finger tight. I'm rather pleased with the end result
Hopefully someone will find this helpful, and if there's an alternative method then please share it here!
Cliff
