Topic: 76 cb550 clear tube test fuel level?

[kippstakes]

My bike, a 76 cb550k, seems to be running rich on cyl 3 (fouled plug/stumbling), so I decided to get my floats evened out with a clear tube test.
I have read that the carb bowl fuel level should be 3-4mm below the flange. Is this correct? When I ran the test the fuel level was consistently even with the flange (except for cyl 3, which was above it by a few mm). The test was done on perfectly level carbs.
Are my floats just a bit wonky and need some tweaking, or is my measurement info wrong?

Thank you

[Duanob]

#3 is definitely too high so while you have to carbs off to readjust that you might as well check the others. The others might be a tad high but you're close. Mine were always 1-2mm below the lip of the bowl. You might recheck the the float measurement as described in FAQs on this board.

[flybox1]

aftermarket float valves usually throw things off a bit.


spot on!

[turkey4me]

Where can we source the brass fitting that mounts to fuel bowl?

[flybox1]

If you have PD carbs, put the tube on the overflow pipe,

If you dont have PD carbs, push/twist the tube into the overflow screw hole, or, a brass fitting can be made to screw in, or get a PVC hose fitting with the same OD as your drain screw, taper it a bit, and screw it in the hole

The thread pitch might also match a brass vacuum sync fitting 

[kippstakes]

Thank you for the replies.
Flybox that's just what I was looking for. Perfect.

My tool to do the test was very basic and worked well.
I had some 1/4'' od clear tubing and a 5/32'' (?) plastic vacuum T connector on hand, so I just melted one end of the T connector shut, plugged it into a ~7'' length of the tubing, put a few wraps of masking tape on the T connector tube, and wiggled the taped end into the drain hole. Didn't leak a drop (it only needs to work on the short-term, after all). The whole setup probably cost 2 bucks.

Thanks again, guys