Typically when gas sets in a carb for a long time alot of it evaporates and you can see in a dirty carb where that evaporation started at usually... it's up high usually so anything at that level...i.e. passageways needs to be checked for blockage usually the float bowl is the easiest to clean.... but I was got by the carbs on the SX650 a few years back as they have a passage way in the float bowl ITSELF !!!! i've never seen that before, but they have it on those carbs !
I had those carbs off 3 times cleaning them and i finally discovered the passageway in the float bowl..... it was plugged in both carbs !
i cleaned that out and the bike ran perfectly after that.
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I have found that a small spring that is uncoiled and straightened out makes a great carb passage way cleaner as it is very strong ( stronger than wire) and can flex without breaking. so you can usually clean the area close to a corner from each direction then flush it out with carb cleaner... that method has served me well for decades.... but you MUST Know where those passageways are in order to get them clean going in without a clue almost always means your going to miss a few.... but unfortunately that seams to be the way I do things ... just dive in and see if i can figure it out and make it work... which usually means I have to re do the job several times !
Thanks to Danno's link there I now know where my blockage is at in the Ninja's carbs i thought it must be there after this last cleaning didn't work but now I am positive ! ( so he says!) so now I am confident I can clean my Ninja's carburetors.... I hope .... I have never had to give up on any carburetor except the AMAL 930 carbs on my Triumph because the pilot jets were not removable.... but I eventually got them clear and it ran great. but I immediately replaced those carbs with an updated version that had removable pilot jets in them !
while the Ninja carbs are still a not completed task i feel confident I can do it
but I will say they are the hardest carbs I've ever worked on... I preferer the older mulkini carbs of the 1970's
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when I take a carb apart I try to figure out how it operates before I do any cleaning ....then I proceed with the cleaning and cleaning to me doesn't mean the stuff in the bottom of the float bowl... it means the passageways
because they are the critical feature of a carburator. although I usually get around to the stuff in the float bowl.... but to me that stuff isn't critical
... and if you have screw in valve seats for the float bowl it's a real good idea to pull them off too , and clean under them real good as that area collects all kinds of bigger heavier particles that plug jets easy.
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when I first got my Ninja it would only run on one cylinder , wouldn't idle till I set up the idle screw and in general only worked on one cylinder even reving it up....
the first cleaning found the main jet completely plugged on one side alot of rust particles in both float bowls and carbs that were in need of a good cleaning in general..... so I didn't really dig much deeper into the carbs and slapped it all back together so I could ride it..... big mistake !
because it did run on 2 cylinders after that first cleaning but it would not idle at all.... anything above 2000 rpm it ran on both cylinders anything below that RPM it just wanted to die.... I rode it anyway.... and was very impressed with the little Ninja ! it had lot's of get up and go for such a small bike !
so I pulled the carbs off a second time and did a very thorough cleaning job
.... but it still didn't want to idle ... it was better but still not right !
I fiddled with the air screws on the bottom of the carbs by the bowls and finally got that cylinder to light up at idle ! I was elated ! but after many startings and runs I have decided those carbs are not clean YET !!!
that left carb was really plugged up !
.... why it takes me 3 times cleaning carburetors now I have no idea ...it never did before.... one of the perks of old age I suspect...... LOL
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Bob......