When Fast One was doing the floats on my carbs (a bank of four Mukunis) he used an ingenious tool. It hooks to your fuel inlet pipe. It is a small air pump which will hold air pressure. There is a small dial guage. He pumps the pressure up to 5 lbs, squirts on some WD40 and looks for the bubbles at the float valves. Bubbles = bad. No Bubbles for 5 minutes at 5 lbs = awesome. Mine held at 3 lbs but not for too long. Good enough for the Show n' Shine, but not good enough for a serious rider, which is now my goal for the GS650.
I have just ordered rebuild kits for the GS650 (a bank of four Minkunis) which come with new float valves. I want to install them myself, and want to be able to perform this test myself.
Here is a picture I downloaded of a genuine Mikuni pressure tester:
Fast One made his own. I am thinking of making my own. I am thinking that a small adjustable pressure guage that they sell at Princess Auto (attaches to spray gun) and some tubing would work. Simply attach to some low air pressure in my compressor tank and adjust to taste.
I also saw some which use a pump ball like the doctors use when testing your blood pressure. I may be able to find one of those.
I'd be curious if anyone else has made one of these absolutely jiffy devices. Beats the hell out of taking carbs on and off the bike to see if they piss all over your bike.
The prescribed way of adjusting floats in the books has always seemed pretty vague, because the manuals describe either measuring the height of the float when it is held just so, or that the float must be at a certain angle etc. The measurement is alway based on "just when the valve closes." Most float valves have a tiny spring loaded plunger which is pushed by the float. With my old eyes, I cannot see when the valve is closing.
I did not watch Fast One fart around with the float levels. I am hoping that he has a quick and jiffy way of getting those right also.
Peace & Grease, Dennis
