To use the spark plug method you have to kill the motor when you are in the band you "normally" ride. ie to test main jet - kill switch at 3/4 to full throttle. To test needle - kill switch at 1/4 to 3/4 throttle. Then check. If you let the motor idle, or cruise home, the plug will show a false reading. One of the problems with unleaded fuel is it runs 'black' on the spark plug.
Here are the specs for the 08 (all free mods done - stock pipe with rear baffle removed).
The details are for Australian Yamaha
part numbers (not sure for US) -
Temperature: 25-28 deg celsius (77-83 deg F)
Altitude: 500-700 metres (1640-2300 feet)
Accelaerator Pump: 2.75 mm gap (.108 inches)
Main Jet: 168
Pilot (slow) Jet: 48
Jet Needle: Yamaha
5TJ-A1 (GDDSQ) clip at 2nd Groove
Air/Fuel Screw: 1.5 Turns out (aftermarket FMSO1 - sunline
NO AIS in Australia
Its currently our summer, come winter - needle is raised (clip 3rd position) and tune air/fuel screw (1.5-2.5 turns out).
This shows a perfect plug. Black on the base (end of thread) and clean light brown on electrode. By the way - rigged up a EGO sensor and it runs stoich - so both plug and O2
sensor methods indicate correct jetting.
Hope this helps.