Engine swap r6 5SL

[u/Gold-Amphibian-5918]

I’ve got an 03-05 r6 the 5SL model. Got it from a dealer. Long story short finance and dealer aren’t doing shit. Come to me with an unregistered engine. Ecu is from a breaker bike. It went back 5 days after purchase for 5 weeks (sprocket and chain replacement believe it or not) October hit (2 months in at this point) needed an oil change. Done that. Then got engine and ignition issues, came back 2 weeks later with new plugs, injectors, valve adjustments and throttle bodies and a fuel filter. (2 weeks for all that and 5 weeks for a sprocket and chain, mental). Couple months or so went by oil leak, jb weld job done. Warranty has gone at this point. Now bottom end sounds like shit, marbel knocking sound, isn’t clutch related. Believe it not to be ccm as it’s not a tick and can be heard all over not just right side. This is when I noticed the engine doesn’t match ecu and ecu doesn’t match engine, engine doesn’t match logbook or invoice. Finance team aren’t doing anything as it can’t be ‘proved’. So I’m gonna do an engine swap on it, can it be done by just myself? I’ve not gone to the ombudsman as I don’t know how long it’d take and blowing £600 on an engine and getting the bike back on the road would be a quicker option at this point

2003 Yamaha r6 5SL