Hmm... From my experience of restoring old cars and bikes (they don't even have to be old TBH), it's a bit hit and miss. I don't think I've ever made a loss on a project but then I've not always made a profit either... My worst case - an old Reliant Scimitar which I bought for a couple of hundred - turned out to be a money pit and I just about broke even. My best case - An old Goldwing that I paid 800 for, did a bit of tinkering, rode it around for a year then sold it for 2k. If you've got an eye for something desirable that needs minimal work and you can snap it up at a good price then you may well be quids in. The pitfalls are numerous - you might buy something that turns out to be an old dog, something that no-one else wants or something less than legal. I've always got something on the go but now I buy stuff that I want and will use until I get bored then pass on to someone else. If I can get my money back (including TAX/MOT/insurance/parts etc) so I get effectively free motoring then I'm chuffed. Just like any investment, don't risk more money than you can afford to lose!