Plugs sooty and black

[xs11widowmaker]

Hi to everyone, I have a 81 xs11sh
I have a 4 into 1 and pod filters. right now I am running 115 main jets. I have had the bike for about 2 years and have tried alot of differant jetting. I just recieved new coils from mikes today. I am planning on putting them on tomarrow when I have time. I also have raised the floats about 2mm (upside down)
Last week I took it to the track to see what it would do, on the way out as long as I was riding 65 to 70 it didnt miss a beat. But when I would slow down it would load up and run horrable. Am I on the right track with the new coils and float ajustment?
Its been about a year since I have been on here, and as always the help anyone finds here is priceless!!
Thanks in advance for the help

[dbeardslee]

According to the fiche, the SH was factory jetted with 110's. With the mods you have, the jetting recommendations suggest that you should be running 120's with 45 pilots. When I first got it, my bike blackened the plugs fast until I upped the jet sizes. Seems kind of strange, as it should have been running lean, but there it is. You say you tried other jettings - did you use genuine mikuni jets? There is a variance in what a #120 jet is from manufacturer to manufacturer, so you can get unpredictable results from other manufacturers jets. I've gotten mik jets from jets r us, and most recently from mikes xs - both with good results. One way you can determine if the jetting is right is by putting a colortune on it. If you can't adjust through the whole range of color, your jets are most likely off. If the jets aren't right, your whistling in the wind trying to get it to run right.

[DGXSER]

Ok here is another thing I discovered...yeah the hard way. IT is unusual and probably not the issue, but easy enough to check.

When I rebuilt my carbs I pulled the needle jet out on one carb and then put it back and realized there was nothign for me to do with that area, so I did not open the other three. After I put them back together, I had one cylinder that would foul out the plug at anything less than 3k. Even had the thing colortuned and synched, and looked good, but continued fouling the plug at low RPM. If you have not guessed it yet, I did not get the needle jet put in correctly. Had the spring in the wrong position. After I fixed that and retuned that carb it has run like a raped ape!! Just one of those if all else seems ot be ok, might as well look things.