If your this way on the bike beforehand gimme a shout

http://s1065.photobucket.com/user/djhea ... t=3&page=1
Here's a link to photos of the scratches on the forks

Can someone please direct me to a pictorial guide on how to check the valve clearances on my GK76A?
I've never done it before, so I wouldn't know where to start.
I know what the tolerances are and I've purchased a decent set of feeler gauges, but I don't want to start fiddling until I know what I'm doing.
I'm assuming that I can do this while the engine is still mounted in the frame?
Got the carbs and all of the cooling system out of the way, so should be a doddle right?
Cheers,
Hubbskiboy.