Took the XX out yeserday after it had sat for a couple of months---after almost high siding himself into next Tuesday on wet pavement---it started kind of gaging/backfiring--it seemed to have cleaned itself out after some more agressive riding---its an '02 w/FI--I didnt even think FIed bikes could backfire

Was the intake stopped up with mice/squirrel/chipmunks or their nests?

Beats me. :???:


Did it happen right after the potential high-side, and clear up shortly after?

Did the bike stall at all? Was this very shortly after firing it up, or a while into the run?

First thing I can think off right away is the BAS getting upset with you over the abrupt side-to-side transition of the high side.

Was the fuel low at the time?

Can FI backfire, absolutely. Just won't afterfire on decel. :sad:

Sat a couple months...is the fuel that old?

Yep didnt think that should be an issue

Prior to the "high side" attempt--it seemed to be running ok. after--I stopped for about 45min--after starting off again, thats when it was really bad. It seemed to have healed after some serious throttle, well see---whats a BAS??--tip over sensor???

You got it.. Bank Angle Sensor.

I dont think so--I doubt the bike angled any more than an average corner

Right.. a lot of folks mistake an afterfire for a backfire. The latter being a somewhat dangerous condition that involves a flame front moving back up through the intake. Alpha - Are you sure that's what you experienced?

You can get an FI-equipped vehicle to afterfire if you have it dump enough gasoline under near zero throttle, off-idle rpm conditions. I had a standalone replacement ECU on my last car that enabled full user-tunability of fuel and ignition versus boost and RPMs. You could tune in some pretty obnoxious afterfiring if you were so inclined. Another way to trigger it is by using RPM limiters or stutter-boxes that interrupt spark, versus cutting fuel...

I agree though, that a well-tuned FI motor should not afterfire under normal conditions. If your FI bird is doing it after being garaged for a long period, I would be tempted to check/replace the plugs.

-Pace

I like the BAS theory. It makes sense given the near highside. Good thinking Chris.

The Bank Angle Sensor would have just killed the ignition just like turning off the engine cutoff switch. The bike would have just died.

Hmmmm---It does have a PC3 on it--I wonder if a wire went bad or somethin---it is also tuned pretty rich via the PC3---but that has been the case for over a year w/o incident. I havent changed the plugs at almost 9K, seems early to me--the 929 went over 17K with original plugs and they look fine when I pulled them

Try bypassing the PCIII, and see if it makes a difference.

That is, however, if it's still acting up on you.