mate .. outside of warranty i'd reckon on £450 for a 6k service (with belts) and about £750 for a full 12k service (with belts), I personally get my belts done each service, for the cost its a worthwhile protection ....

other than that its tyres and insurance and thats as much about you and the way you ride as it is about the bike ....

I reckon £4500 would see you a mint 748 bip ....

happy hunting