Does anyone know where I can get some barbed fittings to replace the screws in the intake manifolds for hooking up gauges? I believe they are metric barbed fittings, which are not easy to find in the US.

They are metric and i made such from allen screws with boring hole throught it. I use under screws such spacers, what have rubber in other side, that there will be no leaks, Simply and function, like trains toilet....

yes, this was a pain in the ass...

similar to Finnpaso - I drilled out some 5mm (from memory??) metric screws and fitted to the vacuum lines.

the problem becomes screwing the f$%^&ers in and getting them firm.
they are also hard to crimp properly in the vaccy tube [ended up using glue].

options:
drill a 25mm long screw and put a nut on it (and snug the nut up) - this will test your skills with a hand drill.

a Ducati shop made some neat ones out of bundy tube (brake line steel tube); they had little "snugging" collars on them; the tubes were long "L" shape (like an allen key) and could be tightened lightly but sufficiently...the rubber hoses slipped over the tube ends after fitting.

I have been considering making some of the same...

So it's not just me! I made a set from the threaded portion of a metric screw. The hole was done on a drill press, so not too badly off center. I don't like the fit without a shoulder so I put the screws back when done tuning. I will see if anyone makes these, or oder some from you Laddie if you want to ramp up production

one day soon I have to set my idle running as well and check the balance between front and rear cilinder. this means I have to make screws to connect the lines.
As I have lathe I can make some more for people who are interested.
didn't look for dimensions so far, but I think to start with 10mm hexagon stainless steel bar.
thread the 5mm, add a bonded seal and a hose connection on the other side.
I already bought already some gauges to measure the vacuum. So, I'll finish the set.

ducbertus

Wow - I didn't read through the whole thread and see what a PITA this is for everyone! Let me try one on my bike next week just to be sure (though I already am sure) then I'll send to anyone for the cost of shipping. The plated ones have a pretty good zinc plating on them and cost me about a buck. If anyone wants the premium SS ones I have to order them in bags of 10.

Incidentally - if you can find a 10-32 threaded fitting it is interchangeable with an M5: the threads are close enough and the engagement is so short you can barely tell the difference.

Hi Sam, they are 5 mm x .8 screw thread, the barbed end depends on the gauge being hooked up. My Mercury tubes are 3/16". Let me know when you have some and we can meet up, thanks
Art