I have just gotten my paws on a k1 GSXR1000 with a siezed motor (previous owner ran it without oil).
Now, I can get a k4 motor in good nick. Will I have any issues fitting the K4 engine, or would I need the ecu as well?
I will start a thread this weekend on the build up with photos,and hopefully be up and running pretty soon.
If you want to use the original K1 electrics, before you swap the motors, you have to take the crank position sensor rotor off of the original K1 engine and put it on the K4 motor. It might be easier to swap all the electrics though as it is behind the cam chain and cam chain guides (head must come off). :cheers
^That's just what came to my mind. The parts fiche shows the K1 as having the two upper mounts on the head while K4 has one on the head and one on the block. Off hand, you might have to give up a mount or swap heads or something else.