XB9 Won't Stay Running/Black Smoke

[mzurla]

So, I posted a couple weeks ago about a charging issue I was having. I thought I had that fixed, then on my way to work this morning the bike was cutting in and out on me and eventually died. I would get it running and go a few feet, then it would die, and that happened several times. It started to backfire pretty badly and was riding really rough. I got it to a parking lot and hitched a ride the rest of the way to work from the lady of the house.

I go with my friend at lunch to check everything out. First thing I do is check the terminals, the positive was pretty loose, so tightened that up, checked voltage on battery (12.3) and then went to start it. It started right up. I think, great, just a loose battery, so I have my friend rev the engine up to 3K while I check to make sure the charging system is good to go. It gets over 13V, so we're good to go. He releases the throttle, the bike stutters and dies. I try to get it going again, it takes a few tries, starts, backfires a few times, dies. This happens a bunch, and on one theres some balck smoke coming from the airbox cover. Is it that I got a bunch of crap in there when it was misfiring and stuff originally? Did I blow the engine? It sounds like the engine is choking due to fuel and/or air. I'm new to bikes in general, and am quite worried. Any advice? I'm gonna have to probably trailer it back to my house this evening.

 

[Cosworth]

See if its putting out a engine code, Id start by pulling the plugs and checking their condition.

 

[WIGGLE2]

Id start by pulling the plugs and checking their condition.

[up]
Check your air filter. It may be a long shot, but if it pushed anything from the breather in any amount, it could have soaked the filter. That will make it rich. I'm 99.9% sure you didn't hurt the engine.

 

[mzurla]

So for an update; with the airbox off I sprayed some throttle body cleaner in there, and also put some STP in the tank thinking maybe the fuel system was clogged up. After this, the bike fired up and stayed running for a couple of minutes. Went to give it some throttle and it died, right back to the way it was before. Bike isn't throwing any CEL codes

I pulled the plugs, they were getting some weak spark (yellowing orange) so I decided to change them anyway since they seemed pretty beat up and I already had the plugs out. Bike still won't start/stay running. I put NGK DCPR8E plugs in. I'm almost positive I have them seated in the boots correctly. I checked the spark (bright white and also managed to shock the hell out of myself in the process) with them out of the engine, then had to disconnect them to screw them in before reconnecting the boots. Also, not sure if this is just me looking for potential issues, but it seems as though the fuel pump sound isn't as much of a whine as it is a hum now. It seems to be a lower note when it primes when you first flip the run switch.

For some history; here are the things I've done to the bike since buying it 3 weeks ago; put LED license plate bolt lights on with positive leads tapped into the brake lights and a ground going to the battery, changed the brake pads for both front and rear, replaced headlights.

Any thoughts out there?