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 Ebay 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.

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


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!