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I did replace the oem plugs with NGK at first to try and see if it fixes my bike.... it didn't. So I took NGks out and bought Autolights to see if they work better, they didn't. I left those new Autolights in the bike and as I was trying to diagnose/run the bike .... those new Autolilghts got destroyed somehow. Finally, when I figured it was a coil (or coils) problem, I got the coils fixed, and reinstalled the NGK plugs ... and now it runs great. I've clened those carbs about 4 times now to try and fix the issue that has nothing to do with carbs, but I thougt it did. HERE IS ANOTHER THING TO TAKE AWAY FROM THIS .... ROTELLA T6 IS A GOOD MOTORCYCLE OIL AND IT DID NOT DAMAGE THE BIKE. (JUST MAKE SURE WHEN YOU BUY IT FROM WALMART THAT IT HAS JASO RATING ON THE LABLE)

SOLVED SO HERE WE GO...yesterday bought a 1999 bandit 600 parts bike for $80 bucks (mine is a 2003 bandit 1200), but the coils do have same part numbers. Apparently my bike had some issues with the coils and they somehow damaged the new Autolite spark plugs. I took the only good (right) coil (for cyl 2&3) out of the parts bike, and also, somehow my (left) coil self-repaired itself and now shows 35k ohms instead of 25 k ohms. I put the bike together and it didn't solve the issues, so I pulled the plugs out and they were very black ... 1 and 3 were dry black (hot pipes), 2 and 4 were wet black (cold pipes). So just for the heck of it, I replaced the spark plugs again with a new NGK set I had laying around. BAM!!! Runs like a brand new bike ...after a year in the reaserch lots of money spent. Long story short, coils get damaged over time, maybe they also damage new plugs. SO, replace bad coils and replace plugs again. Try running it again. Funny thing is I had 3 sets of plugs (3*4=12 plugs total) and original set got toast probably during the initial coil failure, second (ngk) set didn't change anything (...so I took them out) because the coil was still bad, and the 3rd set (autolites) got damaged because I kept trying to run the bike with a coil (s) still bad. So when I got the coils fixed, and reinstalled the NGKs back, problem solved. Thanks again for all your help. There is a guy on youtube that has been trying for years to figure why his bandit rans like crap. He did all the things I've done, and it's probably just the coils and plugs. ))) ALSO NOTE: if you are buying cheap $30 coils from e Ba y ... then, you have to take the original bandit boots and install them on to the new coil wires (don't use the e Ba y's boots as they create different amperage than the OEM bandit coils boots).

Thanks for the reply. Will check tonight. Wouldn't I get at least a back fire if it floods those clylinders? It doesn't back fire. I do seem to have some spark on all 4 cyl. ALSO PLEASE NOTE something very interesting: LEFT coil runs ***cyl 4 (coli TOP) and cyl 1 (coil bottom). RIGHT coil runs ***cyl 2 (coil TOP) and cyl 3 (coil bottom). Do you see how the cylinders powered by the coil top wires don't run....and the cylilnders that are powered by coil bottoms do run....and that's with the old coils and new coils.... is there a possible correlation?

ENGINE OIL i'M RUNNING 15W40 ROTELLA T6 ... for diesel trucks, but JASO certified. If that oil would damage the valves, then I wouldn't have good compression....right? I've read people using that oil on many bikes.... and I used it on my first bandit 1200...which also had similar issues as this one.... hmmm

About a year in the search of the problem so far.... The bike has 6,000 miles, was riding perfect and one day just pulled it out of the garage, started it and it would not run right. After a while found that cylinder 2 and 4 pipes are cold. The bike is running on 2 cylinders. Work done so far to try and diagnose the issue: 1) Replaced spark plugs (Twice) 2) Replaced the coils and wires with $30 Eblag ones (for some reason old coils and new coils only show 26.5 resistance on secondary winding ... should be 30 to 40 k Ohms, but primary resistance is 3 ohms; which is fine (should be 2.0 to 4.0 ohms). With new coils/wire 2nd cylinder pipe did get hot (once), but 4th still was cold, at later tries 2nd and 4th still stary cold (Note: I did NOT mix up the plug wire locations or the wires coming from the bikes to the coils) 3) I left the plugs in the engine, got spare plugs, connected them to the plug wires and layed them on the engine. Cranked the engine and saw all 4 sparking. Although 2 and 4 may have a little bit weaker spark ( or Im just goin nuts). 4) Replaced carb boots (going to the engine) ... and noticed the intake valves were clean clean on 2 of the 4 cylinders and dirty on other the other 2 cylinders ( don't remember which they were...probably ones that don't fire) 5) Cleaned carbs (4 times and measured float bowl height) 6) Replaced the little rubber nipples on top of the carbs. 7) Adjusted the valves (They were ok to start with). 8) Checked the timing chain tensioner (it's ok) 9) Battery is well charged and always on bat. tender 10) COMPRESSION IS NEAR PERFECT on all cylinders no deviation between them. 11) Air filter is the hiflow (I know it likes oem,but it ran perfect with hiflow and it's 99% unlikely to be the problem) THE LAST THING THAT COMES TO MY MIND IS THE LITTLE "IGNITION CONTROL UNIT" ... little black box under the rear fairing. According to hayne's manual it's impossible to diagnose/take apart at home. This is my second bandit 1200 and it has the exact same unsolved issue that happened suddenly. I sold the first bike as is ,but I am just really curious why that issue keeps happenning on bandints 1200. I want to fix it on this bike. I know the bike is awesome and super fast. THANK YOU THANK YOU THANK YOU!