Topic: 022a carbs

[luap]

stumped even after following other threads an doing a couple other bikes an having 2 other bikes in good running order in my garage, this one is a cb 550 1975,
what Ive done,
-rebuilt tops end vesrah gasket hone cylinders lapped valves, gapped valves static timed, new wires ngk caps plugs dyna coils intake to carb bootys, rebuild carbs after disassembled (cleaned 50/50 simple green water two cans of carb cleaner a piece
So I fired it up the other day only getting spark out of 1/2
going through the check list pulled carbs off cleaned all passages on carb 3/4 double checked slow idle main needle jets all clean, today being the 3rd time, floats set at 22mm
reracked the carbs good supply of gas crakced drain plugs lots of gas
bench synch with drill bit, havnt done vaccum synch yet
checked for leaks with wd at both ends of the bootys checked spark at cap an also with spark plug in the cap good spark, thought about timing but 1/2 are firing fine so elimintated that
checked compression dry an wet good compression
pulled plugs after I fired it up dry plugs on 2/3
hooked up the air compressor to supply line for 3/4, get a over flow of gas at the filters
also shot air through all of carbs, intake manifold screw are in an tight
Shot some WD40 an got 3/4 to fire, also put my hand over carbs alot of suction
any insight on what to check
inline fuel filter new fuel lines
thanks paul

[w1sa]

If you're cold cranking with good/fresh clean,dry plugs and you pull dry clean plug(s) from the engine, its a strong bet that you've got a blockage in the slow speed circuit between the slow speed fuel jetting and the air passage that mixes the air/fuel for delivery to the carb bore or.........a blockage at the mixture entry point into the carb bore or......fuel level in bowl(s) is too low......or some combination of each.

[luap]

back at cleaning them today, one thing I did notice was the small 1/4 line that goes bewteen 4/3 then to the breather vent I only get air coming out of 3 an nothing from 4, would that affect dry plugs?
I have gas in both bowls an I thought that breather would be to allow air to escape, Its gonna get pulled an cleaned,
blowing air through the same breather on 1 an 2 I get air coming out of both overflow vents
Just curious if that would cause the problem

[w1sa]

I dont think poor venting would cause dry plugs at start up, but could interfer with good fuel delivery while running.

Make sure the jetting is real clear and clean.........inject carb clean solvent down the air passageway (houses the airscrew and goes between the carb mouth and the jetting inlets and then the carb bore outlet) and up thru the base of the jet housing....let the carb clean soak some then airblow thru.........then repeat until you see carb clean atomising out of each hole (just like pure fuel would)...you must see clearly thru jetting etc when held to light.........dont get carb clean solvent on or into plastic/rubber parts etc...it eats them.

[luap]

turned out to be float level. had them set to shop manual 22mm reset them to 20mm now everything is firing, next step figure out the 25 degree difference between the headers after warmed up, thanks for the help

[Duanob]

I'm a bit confused! Are 2/3 not firing or 3/4? If 3/4 start with the obvious, make sure you have enough fuel in your tank (hey it happens!) Check both your fuel tap drains to make sure they both have good flow since one feeds 1/2 and the other feeds 3/4. in the end you might have to take the carbs off again and go through them again, vents, pilot jets, float levels, etc. I ended up doing that 3x tp fianlly get them perfect but that's what they say, third times a charm!