Not sure about you bike but the clutch plates normally have to go in the basket a certain way. 120 degrees rotation with the dimple. So 12 oclock, 4 o'clock and 8 o'clock. There may be a special circular plate that has to be fitted also. As I say, it may not apply to your model but I know it does to many old yami's (including my YA). The plates may be contaminated if the wrong oil has been used or it could just be an adjustment issue.