Can anyone tell me the procedure for this? Thanks.

 

Heres a generic article on valve adjustments, and should help describe what needs doing.
The toughest part, is removing enough stuff, to get to the valves, like fenders and gas tank and such.
the rope pull will need to come off, to access the sight plug, to line up the t mark, on the flywheel. The valves are adjusted cold, and the intakes are supposed to be .0024 -.0039", and the exhaust is .0063 - .0079".
article

 

Hey thanks. I guess all i needed to know was were i could find the timing mark on the 450.

 

is this a task the average guy can do? or should it be going to the dealer?

 

I would think the average guy can check them, and if they are ok, then you saved money. If they are out of tolerance, then you can decide if you want to keep going, or button it up , and take it to the dealer.
If you can change oil, and spark plug and other basic repairs, then this shouldnt be very tough.