i have a 98 xr 80 thats been sitting about four years i rebuilt the carb clean out the tank new plug new oil it runs but smokes alot {white/gery} spits and sputters but in the high rpms it runs ok wont idle at all its building up compression in the case if you pull the dip stick out after riding it shoots a big burst of air out not sure but d0nt think is normale any idea's with whats wroung with it would help