I dont know who manufactures the engine I have heard all sorts of possible manufactures mentioned, but if you want information on the bike try this italian site. You can download the entire bike parts drawings for the Canyon 500, broken down by section ( engine , frame, electrical etc). I have just purchased a starter motor for the bike from them and it arrived in 4 days and was cheaper than the quote from a UK agent.
I have also emailed them for technical information (Valve clearances) which they emailed back to me with information taken from the workshop manual ( The UK importers refused to give me the information as I was not a dealer!). The company is based in Varese and must have pretty good access to the Cagiva factory.