Yes, Spray every thing then when you ride it wont get as dirty and when you spray with hose to clean the dirt almost falls off by its self.
Here are some pics of an 04 to show how a bike looks when you keep sprayed with wd-40 after every time its cleaned and sprayed down after every ride.
I usually use simple green to clean my bike. One thing I would not advise is using wd40 on your plastic. Wd is a degreaser, and it will take the shine out of your plastic. Learned this the hard way. Had a new set of Maier Ballance edition plastic and I thought after a muddy right I would clean er' up. After I had wiped down my rear fenders I noticed that the shine was gone. i even tried it on an old set of stock plastic and it took the shine off. If you want a good shine on your plastic I would just use simple green.
Use Pam cooking spray under side of plasticks, chassis, etc. Works awesome, just like WD-40 but not as toxic LOL! PJ1 makes some awesome rubber/vinyl/plastic shine spray for the top of the plastics. makes them look new again.
WD40 for the frame and engine(mud will felt off more easily)...but this stuff will loosen the bolts of all the F----g quad! Everybody that knows kawis know the loosen bolts and nuts all over the place... so be kind near the nut/bolts...