Great thread, some really useful info coming out of the woodwork! I see a few questions related to porting and polishing so I thought I might share this, there's some very helpful info here :
DIY - Basic Cylinder Head Porting -Standard Abrasives Motor Sports
And this other Link is to a general "Bike" Tips page. This place is a great site to have in your Favourites! It's helped me plenty! The Guy who owns it seems a bit odd sprouting religous quotes here and there but all in all a very informative repair / tips guide. Check it out, you'll see what I mean!!
Motorcycle Repair Course