Do all your adjusting/inspecting in a room temp. shop or garage.
Be sure your motor is clean of dirt and anything else that could fall into the motor. Air compressors work great.
Start by removing the seat, fuel line, and fuel tank.
Remove the four valve inspection bolts. (24mm)

Remove the spark plug, and the timing inspection bolt and the lower one covering the flywheel nut. (6mm allen wrench, 10mm allen wrench)

You want to adjust your valves at TDC (top dead center) of the compression stroke. Watch your valves. This is when your intake valves open, then close, then roll the flywheel to line up the "T". You should have play in all 4 rocker arms.

Since this bike has an auto-decompression system, this is easiest to do with two people because the flywheel has to be turned over very slowy so the auto-decomp doesnt engage and the force of the valves closing will make the flywheel spin faster. Have one person push down on the kickstarter while the other person has a ratchet with a 17mm socket on the flywheel nut to slow it while the valves close. After the intakes close you can line up the "T" with the ratchet on the flywheel. Take off the manual decompression cable, it just gets in the way.

Take your feeler gauges and check your valve clearances. (.004 on the intake, .005 on the exhaust) If you can get it in without struggling and there is just a light grab on the finger it is perfect so don’t adjust it. If it to tight or loose, adjust it. Check the exhaust clearance using the correct feeler gauge.

Adjusting the Valve Clearance.
Start by loosening the locking nut. Using a flat head screwdriver, screw the adjustment screw out just enough for you to slide in the correct gauge finger. Screw the adjustment screw back in so it is just applying a small amount of pressure to the gauge finger. You should be able to still slide the gauge finger around, but it should feel like it is grabbing a little. Screw the locking nut down to secure the adjustment screw. When the locking nut is tightened, it appears to raise the adjustment screw slightly and reduce the amount of grabbing on the gauge finger, so experiment and get it all tight but with the slight grab.

Continue this for the remaining three valve clearances. Tighten all locking nuts on the valves roll the engine over to TDC of compression stroke and check clearances again. Replace valve cap covers, timing inspection bolt, sparkplug, and flywheel nut cover. Replace tank, fuel line, and seat. Be careful of the routing of the cables and wires. They all go inside the tank mounts.

 NOTE: turn the engine over very slowly as to make sure you do not engage the auto decompressor. If the engine is turned  backwards at all this will also engage the auto decompressor. If the decompressor is engaged whilst adjusting, the valve adjustment of the front right hand valve(this valve is the one opened to release the compression) will be nowhere accurate. this will cause a loud ticking sound and the engines performance will be reduced greatly.

Now, my mates bike starts and runs like a dream!
Hope this is of help. Feel free to comment and ask questions!