carbs -couple questions

[oldyam80sg]

I removed the carbs on my 80 SG after I rode it to my storage unit. I proceeded to start stripping it down to clean the carbs and noticed some things. 1st- # 3 carb float bowl was dirtier than the rest. The other bowls looked surprisingly clean. 2nd- the butterflies facing toward the engine were dirty with some crud-is this normal? The rest of the carbs were not bad looking but did notice these things. Thoughts? I will further strip the carbs down and set the float levels.

[DiverRay]

There could be a number of things causing your problems. I would start with the "O" rings for the seats in the carbs, if you saw a lot of black bits. Second would be the valve adjustment, is #3 intake at the low end, or tight? How about the exhaust valve? Third, is the plug cap still at 5K Ohm, or is it greater, say 7K or more? All I can think of on the cold night...

[oldyam80sg]

No black bits at all. Just dirt that some carb spray on a rag fixed. I will strip everything down and inspect thoroughly. The bike ran good on a 40 degree day. I didn't ride it for a good month+ due to rain and constant knee issues. Started the bike and ran it until the carbs ran out of fuel.

[DiverRay]

You may have just puller the last of the "junk" in the fuel system into #3. If it was running well before, I'd not worry too much about it.

[Radioguylogs]

Seems to me the only way #3 float bowl becomes more dirty is if the previous cleaning job didn't get the input pipe and the float needle filter as clean as the other carbs.

Regarding the other question, the butterfly valves have been really clean on every set of carbs I have ever pulled. I wonder if your air filter is doing the job? Air leaks between the air box and the carbs?

[LAB3]

I've seen the dirty butterfly issue before, check those valve clearances! A little crud in one float bowls could very well be an old fuel line breaking down. If the bike runs right do your regular maintenance and if something isn't broken don't try to fix it!

[oldyam80sg]

No airbox and am running APE individual air filters. Butterflies were dirty engine side of bike not air filter side. Going to thoroughly clean everything.

[oldyam80sg]

When taking the carbs apart and cleaning them, where the float needles sit, when you take the float valves out, I sprayed carb cleaner and some gunk came out of the small passages at the bottom. I sprayed some more cleaner and used compressed air to clean this area real good.