I just bought a brand new 2014 xmr 650 and took it in for it's 10 hr service hoping that would solve it but it didn't. I can wheelie in low if traction is perfect or I hit a bump than punch it. In high it barely raises the suspension with no chance of wheelies. My friend has a brute force 750 stock and can wheelie anytime in high range. I love my xmr but am very disappointed in the lack of power. If anyone has any suggestions I'm all ears