Mine shook and vibrated too, I tore mine down to inspect the pistons at about 1800 miles and luckily caught a cylinder crack on the intake side of a cylinder skirt. I was planning on replacing pistons anyway which had a lot of collapse on the piston skirts. I think this is the main reason the cylinder cracked. I will be starting to put it back together soon so I will have to see how much smoother it runs when done. While I had it apart, I sent my primary clutch to Indy Specialties in Welch MN to ave it trued and balanced, it came back looking like new with new bushings etc. I sent the weights I was going to use with it so he fit the weights correctly and also set the belt clearance for the belts I am using. They balance the inner sheave first and then put the clutch together and balance it again so if you ever have to add or remove shims it will stay in balance.