S2R 800 running a little rich

[MostroS2R]

I got an 07 s2r800 with udder only. I get a few backfires on deceleration but not always, less than 10% of the time.
I pulled my plugs and found the front cylinder plug to be black, and the rear cylinder plug a nice tan color.
Is it easy to adjust the AF screws to try and lean the front cylinder a little?

Also, bike is running between 200 and 220 in 82 degree weather.

[hackers2r]

Don't think you can adjust fuel mixture like that.  There are plenty of options for adjusting A/F ratios.  Search it up!

[booger]

You should sync the throttle bodies, the air bleeds are for idle but do lean out/richen when respectively turned out or in to a small degree. If you haven't done anything to adjust fueling with regard to the ECU and are running a stock config then you will run lean with full stock exhaust, leaner by running just the udder. You should take the bike in for an adjustment. 200-220 degrees doesn't seem that out of whack to me. From my own experience that's normal. But the differences in plug appearance does seem abnormal. The factory shop manual can help with the sync, you need a dealer or VDST to adjust the fuel trim.

[MostroS2R]

It was done last August when I had the valves adjusted and belts changed.
Does it have to be done ASAP? No more dealer in my area and the closest dealer is about 100 miles.

[booger]

I think if you did a sync you might be ok, try and find the shop manual online and download it. I can't remember where I got it but it's out there. It entails fully seating the air bleeds, syncing the TBs with vacuum guages or a manometer(which you can make yourself), then backing the air bleeds back out again until a proper idle is reached. At that point you would be at the factory setting or thereabouts. For a fuel trim you would still need something to interface with the ECU(dealer or VDST). You could pull the plugs, take a good photo of each, then ask somebody else like Brad Black about how urgent your situation is. To be safe you could put your mufflers back on.

[MostroS2R]

I'm not worried about the bike being lean, it's a little rich, I can smell it in the exhaust.
Wouldn't putting back the exhaust richen it up even more?

[booger]

Well if you're running the stock ECU which is set lean to begin with, and haven't adjusted the fuel trim @ the ECU, then balancing the TBs + setting the idle should put you @ factory spec for North American bikes which is known to be lean. If one plug is black back the air bleed out for that cylinder and see what happens. The thing is all fueling adjustments have to be done in concert and reconfirmed because all adjustments affect each other.

[MostroS2R]

Can anybody point me to where the airbleed screw is? Got a pic or something. Been searching but haven't found anything yet.
Thanks

[brad black]

http://www.bikeboy.org/ducati2vthrottleb.html  everything apart from actual tps setting applys to the 800 as well pretty much.

you can smell the hydrocarbons, and that can be too rich or too lean or generally running badly.  i'd wind out the front air bleed.

[MostroS2R]

Thanks for the link.
Would winding it out lean it or richen it?

[devimau]

you close it you rich it up, you it open you lean it out, just open the front bleeding screw 1/4 of a turn and try it, then if needed  do it by 1/8 turns if you don't have a gas analyzer.

[MostroS2R]

Backed out the front air bleed screw on the front cylinder, couldn't really try it out on the road since it's raining.
Did notice that it doesn't smell as bad and when reving it there is less smoke.
I'll try it tomorrow if it's nice and then check the plugs again.