Alright guys I have some questions? I have a 2006 CBR600RR that the motor went in and now in need of a new replacement. I found a 2004 CBR600RR as all the rest are way to expensive, my question would I need to change anything to get it running. Would my current new 06 ECU and harness wire upto the 04 with no issues ? My next question would the heads from a 05-06 600RR work on the 03-04 600RR ?

 

I think the '06-'07 bikes have the better engine from what everyone talks about. Big changes from the previous generation, and even supposed to be better than the new ones. I'd suggest staying with one from your generation.

I could be wrong tho, possibly parts are compatible?

 

From all of my research my 03-06 600RR is exactly the same with very minor differences