my son has a typhoon 110 that has no get up and go.When we go riding he spends most of time pushing quad around up any incline or from a dead stop.When it finally gets up to speed it cruises really well and is quit fast for a 10 year old.When you put it in reverse it will bury the back tires,and has plenty of torqe and power.When put back in low it revs out but doesnt go anywhere.can someone please help me on where to start looking for thing to fix.Might just be easier to replace entire motor and transmission.PLEASE HELP