Hi guys, Brought myself a CBR 600 F4 about two weeks ago, and its been running sweet untill tonight when she dropped two cylinders suddenly while riding. Stood by the side of the road looking like a sad sack for about 10mins while i waited for the headers to cool down, started her back up to find that #2 and #3 headers stayed dead cold..

Now normally i would think that one of the coils was playing up, but seeing as this bike has a direct ignition coil for each plug, loosing two at the same time seems kinda unlikely..

Should mention that three days ago I installed a manual APE cam chain lifter, and checked the valve clearances while i was in there (clearances all within spec) but i cant think how i could have stuffed any thing up to cause this problem. The bike has been running fine for the last 3 days after these changes.

Carbs were cleaned out about a week ago.

New plugs last week.

Could be a ECU problem? Anyone know how to diagnose a faulty ECU?



Any ASAP advice would be awesome as im suppose to be doing a tour on friday!

Cheers, E

 

Certainly sounds like coils, but as you point out - unlikely. Could it be the ECU ?- again, unlikely as they generally work or they don't - sounds like a fuel blockage - that's where I'd start, but checking you have spark to the plugs will eliminate the ECU as a suspect before pulling the carbs. Maybe loosen the fuel purge screws on the bowls to make sure they all have fuel.
Did you perhaps dislodge some wiring - a long shot I know but at this stage I'm looking for clues - did both cylinders go out at the same time, or not ? Was there any warning or did it just quit on you ?
Let me know what you find.