After continually fiddling with my SU's I've created a fairly inexpensive Sightglass for my carburetor float bowls. My device will allow me to see what the floats are set at and ensure that the carb gross fuel mixture setting is correct. Then I'm able to dial in the fine mixture setting with the adjustment knobs on the nozzle to get back to factory specs.

Would there be interest from any members in a set (allows you to see levels in both carbs at the same time)? I'd be willing to provide 2 sightglasses with instructions for $15 including shipping anywhere in the US. PM me if you're interested and I can provide more detail.

I did take my cork gasket off and put it in a book to try and keep it straight. 1/2mm off isn't going to hurt anything, just as long as you're within 1mm it's all good. Unless you want to be exact and want to adjust each of the screws exactly the same amount of turns to get the mixture set( ztherapy quote 2 carbs as one).

Jeff -- This is brilliant! Great idea and the picture is worth a thousand words

Thread pitch on the drain plug is 8mm x 1.00mm.

I read a suggestion to just get a few M8 x 1.00 zerk fittings, drill them out, and use clear tubing. That's about $1.50 worth of stuff (or $7 with a ton of extra stuff). Worked great.

Simple and effective. BTW once one float is set where you want it, you can move the tube in front of the nozzle and make marks (or just eyeball both sightglasses) at that fuel height just below the mouth of both carbs. Then adjust the other float so fuel level is same height at both nozzles. Eliminates the difference in bowl levels due to engine tilt or rake, and lessens the chance of human error.