Rich problem at part throttle

[JasonB]

Ok bike was running great yesterday morning. (and previous to that). Let it sit while at work and come out and the choke doesnt seem to work, it wont rev up like usual with the choke but I can see the cable and etc moving on the carb like it should. I let it warm up for a while and no change with any choke position. I get on and ride it and at part throttle 1/4-1/2 its bogging like when your low on fuel I rev it up and it revs fine. I flog the bike up to the rev limiter WOT and it runs fine. Only part throttle and lower rpm's does it bog. I take a look at it today and the plugs are black (they were a nice white/tan before). Check the choke again and it looks to be working fine as far as the cable goes etc.

K&N Pods, 140 mains, 40 pilots, 2.5 turns out on mix. Was running great like this before. Last night weather was 70ish down to the 60's.

Ideas?

[The Buddha]

Stuck float or blocked or partially blocked air filter will be my first guesses.
Cool.
Srinath.

[JasonB]

Filter looks nice and clean, hasnt been on that long, will look at it.

Float stuck would have to take carbs apart correct?

[The Buddha]

Floats sometimes release themselves... A little tap on the bowl or a ride on a fairly bumpy road will release it. Funny thing is if you set them too high (usually creates issues of its own) is when its most likely to happen. So check and see if its a float by u tube method and see if it takes care of it if you set them right. Also the third possibility... I have never seen it happen in a GS but GSXR's and other bikes with 40K+ have a habit of egging the emulsion tubes and sorta wearing the needles as well but the needle length minimizes the wear while the emulsion tube's face that is sticking in the venturi wears the most. (Check out factory's site for details) Will make it rich on the needle. However I doubt it happened on yours and certainly not an instant phenomenon. My $$$ is on float stuck... My vulcan has done it at the most in opportune time and place and I had to borrow a plug wrench (I know shame on me) from a girl co worker (double humiliation cos she told everyone next day) who had a SV and was saying it was old crap so its broken, and I had hydro lock...and I pull the plugs out and turn it over by hand spewing gas everywhere.. then with starter and then plugs back in and it starts... and she goes very impressive Srinath... Whooo hooo. BTW side draft carbs usually dont hydrolock... they flood the airbox.
Cool.
Srinath.

[JasonB]

Took the carbs off and the floats look ok, they werent stuck it didnt seem. Guess I'll have to do the float level test and see where they are at.

[JasonB]

For some odd reason the bike just decided it didnt like the washers under the needles anymore. Removed them and re-did the mix screws and it runs great.

[The Buddha]

The washers ren't that great a deal... I put some very thin ones (1 in each) in Gino's bike, DonD used some thick ones 2 of them. It probably would have been OK in both cases. Does Your needle or emulsion tube have visible wear??? That may be the reason.
Cool.
Srinath.

[JasonB]

nope both looked good, bike only has almost 9k on it.

It was doing this a little before where it would load up with fuel at idle at lights I just blipped the throttle and it was fine. Then this problem with the stumbles at part throttle came in. It does it just as the needle comes out of the jet, the bike runs black smoke rich until you open it up and then its fine. Some reason it got so bad that with the choke on it was too rich and the plugs were black as night. Tried turning the mix screws in from 2.5 turns and it didnt help at all. I had 2 washers on the needle, removed both of those and all is good now. I am at 2 turns out on the mix screw and off the line and part throttle is much much better.

[The Buddha]

Well whatever works... Curious that it did it just as weather was getting colder...
Cooll.
Srinath.

[JasonB]

Well when it was real cold here (30's in the am up to 45-50ish) it didnt do it. But when it warmed up to mid 50's overnight and mid to high 70's during the day it started. I usually rode when it was in the 50's in the morning and the 60's at night so not much difference in temps. Cooler should make it leaner not richer.

Ah well it works now and thats what matters. I did have a bunch of rust dust from the tank in the bottom of my bowls, fuel filter doesnt seem to catch all of it. Gonna Kreem/Por my tank when it gets too cold to ride.

[The Buddha]

Well that makes sense on the temperature thing.
Cool.
Srinath.