I'm sure it has been previously often discussed but here one more time, the story of my carburetor cleaning and overhaul, because my motorcycle has exhibit symptoms of not properly running which i often see from other members here.
From the beginning I own this bike, it had this typical problems with carburettors, rpm hanging on throttle snap, bogging while driving (first gear just rolling) in to the roundabout for example, super rich on snap wide open under load (overtaking) spark plugs completely black, carbs overflowing or air locks in the fuel line, no problems starting cold thou, but when warm, after standing for 30 minutes or so it was a b**ch to start up again. So here some description and pictures how I resolve those problems to help others tackle theirs. This is how I did,,,,,,, but a lot of tips are coming from Scotch, who is very very experienced in this field, and so first of all I thank you for the help mate.
First obviously disassembly, cleaning, boiling it in distilled water (don't use normal water to boil, it will leave nasty scale stain on and inside of the carb), flushing, blowing with air. I have build cleaning pump, it can move the liquid (fuel, thinner) for and backwards and also I can supply the air in to the system, this because I find that air bubbles help to break off the rust stain or particles in some of more troublesome areas of the carburetor.
And also prior to flushing I soak them for about 20 minutes in Tangit, [(don't spill it, it will burn hole in you lawn, or in the garage floor, also if you take it too long it will start to dissolve the brass gallery pin seal ] to remove some of the stain in the galleries, than I blow the passages with probably enough air to supply the whole planet. After I clean them thoroughly I drunk one bear, and than I started all over again, just in case. You could skip the step with the beer if you want, but I really don't recommend this. For soaking in Tangit, I have removed all the jets, everything else including the butterfly valve and seals, ONLY carburetor body and brass gallery inserts (once I even drill them all out to see what's behind, picture later) remain, any plastic or rubber parts would have dissolve instantly otherwise.
After that as the first step, the assembly of the butterfly valve, with new seals and using loctite 243 thread locker on the screws. Putting the butterfly valves in the shaft slot is difficult at minimum, it requires concentration and steady hand, (if you tired don't do it), return spring must be hanged AFTER you put the screws in both valves. In later stage, while sliding the plates in the slots when about 90 percent of it is in the slot it self, you should move the shaft left and right slowly, repeatedly, with no pressure at all while very very lightly closing throttle in order to set the plates to fit the bore of the venturi (that's the difficult bit) and when they are in, you need to center the holes for the screws (they should already almost fit) almost in the middle for both holes in both valves. Verify the fitment of the plates (by looking through the venturi to the light) before putting screws in and hold the valves closed with the finger on the lever. Next steps: Plastic washer, circlip, and the cap (cap only once, on the left and right carb body) and than so hated leaky needle valve, holding plate, and microscopic size retaining wire clip, emulsion tubes, main jets, idle jets, the plug screw (everything proper clean), float plus pin, finally the float bowl. You done.
Now to the top, first thing I have notice was when applying choke (fast idling cam action), on the left side of the carb link rod was moving down more than the right one, due to play the linkage shaft has developed in relation to the cap. Repair was more or less straight forward, drilling out the bore, making and fitting brass insert using loctite 603 and than reaming the hole to the size and putting all the parts of the pulley together again. Than goes the membrane and slides with needle set to standard spec at first, (circlip in third notch counting from the top or bottom if you have needle with 5 notches, some of the first needles have had only one notch) and finally the cap with four new hex screws, on the left side enricher, membrane with spring, seat and cover. That's one of three carburetor done.
Also while I had them parted I have made new fuel connectors out of brass and with viton o rings (size 7x2 mm). T part is made out of two parts obviously and soldered together using hot air gun.
After i have read the article about carburetor restoration written by Scotch, l build those brass floats, the bodies are coming from bing 32 carburetor if i remember correctly and the arms i made out of brass stripe using the jig.
Also while I had them parted I have made new fuel connectors out of brass and with viton o rings (size 7x2 mm). T part is made out of two parts obviously and soldered together using hot air gun.
After putting all together I set the fuel level to various heights, re-jeted the carb in different combinations to see how it reacts while trying to tackle the wide open throttle rich condition and off idle bog. Also driving with restricted filter or completely open air intake.
All in all it turned out that for me the ideal jetting is main 110 idle 47,5 and the idle screw 2,5-3 turns out it varies between the 6 intakes and is set with color-tune plug and the needle at 4-th notch counting from the bottom. Fuel level sits at 7 mm from the bottom edge but with tendency to 7,5.
I forgot to add, the choke plungers have got now also new viton seal made out of viton sheet.
And also troublesome areas of the carburetor mentioned earlier.
To be able to jet the carburetor or better to say to see what I'm doing I have build lambda sensors in collector boxes under the oil pan, so I can tell what changes is it doing to the engine behavior.