dear guys, I am rebuilding a YZ450F and everything is OK, but a transmission. it felt perfect on 1, 2nd gears, but slight hesitation on 3rd and worst on 4th gear. It feels like clutch keeps ON & OFF as frequency. It accelerates and but still hesitating. I tried to remove TPS, and gonna lower clutch disk numbers (I put as many as it can take). I checked condition of transmission gears when it engine was open. But everything and every gears' condition was mint. Please help. What would be the cause??? What should I do? WHat should I check next?