Another Carburetor Project.

Now I see why the previous builder may have failed to set the fuel levels correctly. The float bowls have drain screws with a M6x.5 (possible .75 thread pitch). I need to drill through three similar brass screws so that I can solder on small brass tubes and perform a wet method level check. I'm told that the previous builder already installed three of Scotch's brass carb floats. Does any body have any idea where I can purchase some of these fine threaded metric screws?
TIA
Bill

Don't know if these Du-Bro cat #241 will fit or not since the drain holes have already been tapped. I got these hose barbs from my local RC hobby shop and I tapped the drain holes to fit. These are a #6-32. Also picked up 1 ft of the clear silicone fuel line to fit the barbs to use as measuring tubes for fuel float height adjusting.

 I see you can also get M6mm x 1mm hose barbs and as an example   EBAY 6MM hose barb



 

That 'Motorcycle Project' site has so much good reading. Thanks for mentioning it, Kawboy.

Carb parts.
At the usual vendors.
Zed-Parts in Britain.
The German Shop.
Both type of carb drain screws . 92066-1064
                                                                1045

Thanks for those links Guys. I'll order some drain screws from Kawasaki. In the mean time, I drilled out a drain screw from one of my spare carb sets and soldered a piece of 1/8" copper tube into it thus:
 
At this point I only have one so I checked the fuel levels three times and surprisingly, at least to me, the 1-2 carb wasn't the highest.
The 1-2 & 5-6 carbs were holding at 1/8" below the top of the fuel bowl and the 3-4 carb was reading right at the top. All three are too high.

The spec is 5mm (a shy 1/4") to 8mm (a proud 5/16") below the top of the fuel bowl. I did this with the bike of the center stand, carbs still mounted.

So still no answer why the #1 cylinder runs so rich on so many 1300s.
Could it be that fuel siphons from the center and right side carbs when the bike is on the side stand? This might cause the 1-2 carb to be flooded.
No, that's not likely it'd have to flow back up through the float valves.
Working on it.
Bill

I haven't yet pulled the carbs but I did remove the cover from the deceleration enrichment diaphragm on the 1-2 carb. I've always been concerned that this enrichment system contributes too much fuel. Here's a pic of the various parts after I removed them:
 
The cylindrical plunger, on the right, fits into a hole in the carb body and supposedly blocks off a passage that adds fuel whenever the intake vacuum rises high enough. My impression of the fit between the plunger and the hole in the carb body is that it's way too loose. I actually took a video of the plunger wobbling in the hole it's supposed to seal but it wasn't of good enough clarity to post it.
One of the modifications I made to my own 1300 was to plug up the holes in the carb throat that admit the fuel for this enrichment system. I know that others have chosen to defeat this system by interrupting the vacuum signal to the enrichment diaphragm but doing so does not address the loose fit I found between the plunger and the carb body.  I'm thinking that even when closed off that loose fit allows excess fuel into the carb throat.
I'll definitely be plugging these vents as I get further into these carbs.
Bill