By putting 22" front tires on the bike you've changed the COG, and put the nose of the machine farther into the air. A 1/2" might not seem like much, but when you're teetering on the edge of balance on a hill climb it can be a lot. Also, it's quite possible the new rear tires grip better than the stock ones did, and that same amount of throttle now sends the nose skyward instead of inducing more wheel spin as the stockers did.
Making alterations to the suspension, specifically lowering front preload to drop ride height and stiffening the rear shock's compression and/or preload should help some.
+1..I'd switch back to the stock tires if you have them or at least with a 21" or taller Rear tire.
2008' Raptor 700R
PC5, Monster Intake
HIPer Tech 3's
+2 LSR DC4 LT A-Arms / Motowoz LT
+2 LSR Swinger / Motowoz Rear Shock
+2 LSR Anti-Vibe Stem
LSR Axcalibur Axle
Pro Taper Evo CR Hi w/ODI Grips
ASV F3 Pro Model Clutch & Brake Lever
Streamline Extended Cables
+2 Streamline Brake Lines
A/C Black Line Nerfs
Blingstar DC Bumper
Blingstar Billet Accessories