Hi All,

I recently had my second ECU Failure in the past 18 months of ownership of my CBR600F4i. The first causation I can assume it was due to previous users using fuses that were rated much higher than what the bike calls for but I fixed that swapped out some parts such as reg/rec and stator and other smaller components. I was out riding recently, and she was riding just fine and shut off out of nowhere and wouldn't prime. After a thorough diagnostic I have concluded it's a bad ECU/ECM module. This seems to be a common problem but for it to have happened twice so close to each other is a great concern because I don't want to buy a third expensive ECU/ECM and have it fail again. I really like this bike and would like to keep it.

Would you happen to have any ideas in terms of finding out the root cause of this problem as well as adding safeties?
Also sourcing or repairing mine professionally, any thoughts?

Thanks, in advance!

 

It is quite rare for the ECU to go bad on the F4i.
As the PO had upped the fuse sizes, it would suggest that he was having electrical problems that are still apparent on the bike, hence the blowing of the ECU.
You will unfortunately have to start looking at the wiring loom for any potential problems otherwise if you just change the ECU it will almost certainly happen again.
Does the bike have any aftermarket changes that you have noticed as this would be the the first place to look, followed by removing, checking and cleaning the connectors.

 

obvious modifications are the turn signals, the bike is lowered, and the exhaust is cut. Aside from that it all is stock. When I first got it there was a wire going from the battery to the headlights I removed it and got the headlights powered via the harness again. Also when I took my stator out the ground test and ohms looked good but there was a small black chip on it that raised some concerns. This was after the first failure. I replaced the stator, reg/rec, and the main relay by the battery. But after blowing the ECU this time the bike wouldn't prime where as when the first one blew the bike did prime but wouldn't turn on. All the connectors that go into the ECU look good and feel good.

 

Would you recommend I removed the entire harness from the bike to inspect and clean? Also, how would I go about cleaning those connectors?

Thanks!