TripleTime's awesome post about his Vincent (cue jealous stare) reminded me that I'd intended to post something about this before I got distracted with other pursuits (and threads!).
I was perusing Craigslist a couple nights ago, as I am wont to do, and stumbled across Vapor Blast Canada (http://www.vaporblastcanada.com/). If you're unfamiliar with the process they're offering, it does this:
It's basically sandblasting, albeit with a finer substrate (than traditional media blasting) that's suspended in water, which is then shot at the object to be cleaned. In most cases it damn near perfectly replicates the original cast appearance of an aluminium engine, and is WAY friendlier than media blasting... I mean hell, you can see how gentle it is on that carburettor up there. It can even give you a surface that's just a few light sandpaperings from being polish-ready. It also is rinsed away far more easily than traditional blasting media, meaning you needn't worry about it gumming up linkages, carb ports and the like.
I know this sounds like an ad, but honestly, I found TONS of references to this pretty friggin awesome process in a whackload of European magazines and couldn't find anyone local to do it when I was rebuilding my '71 Yamaha motor a few months back. British bike guys seem to swear by it as the single best way to clean everything associated with motorcycle motors, so I was nerdily excited to see a business crop up here in Vancouver offering it, and figured it was worth throwing up on BCSB for anyone that might be looking to redo an old bike in the future.
By the by, I am in no way shape or form connected to these guys, nor have I had the good fortune to need their services just yet. It's more just a head's up. I know I've got a few motors in storage that I'll be bringing to them, so I'll let you guys know if it goes well!