Would a headgasket failure cause it to lose pressure at higher rpm? Iwas taking the quad apart to check carb and I noticed smoke from where the exaust meets the head. Little pieces of gasket sticking out inbetween the head and block. If so how hard is it to replace? and about how much$$. Thank you!

 

The little dimple that sticks out is normal, probably has a tiny rivit in it. The leak is probably the valve cover gasket & cover warped.

 

shouldn't be that hard or that expensive just pull the head bolts out. scrape off all the old gasket and putt it back together using factory torque specs