10-01-12, 01:53 PM
It's a fairly tight squeeze to get the engine in and out... you're unlikely to get a litre-sized one in without major modification to the frame. The Thundercat looks like the throttle bodies would be fouled by the frame too as the inlet tracts are are a steep angle. I'd stick to replacing with another FZS600 motor and, if you want more performance after that, sell it and buy a faster one.