question for the engine gurus: concerning vanilla milkshakes and breaking gears
 

Long story short I have 2 bad 4fi's. One sustained damage after it had went off the side of a mountain. It was in gear when it happened, and now the engine makes a ticking noise when it runs. My best guess is the clutch basket, but I've never had a bike engine apart and don't know what's the weak points. Here's what it sounds like.

The other one I picked up couple days ago. Dealer got it as a trade in and with 40k miles "it's too many to sell" so I picked it up for "parts" I drove it down the street. Ran fine. No smoke. Just needed pads and a valve adjustment. This morning I start it and it's sluggish when I blip the throttle. It hesitates for a second before the rpm go up. I was told out of spec valves could do that. Anyways I check the oil and holy vanilla milkshake. Can it be a head gasket even though it doesn't smoke? Or more likely cracked head? After I took it apart I saw that the radiator was damaged and it barely had any water in the system.
Here's how it sits now

imgur: the simple image sharer


So what do the experts say? How hard is it to take one of these engines apart? Any tips or tricks? Do I need to deck the block or is OK to just shave the head?