Originally Posted by Falcon Rust
talked to a mechanic a couple of weeks ago and he suggested that changing the piston, could really improve the vibrations and relax the engine. as anyone done that?
I moved to a Wossner piston (due to a inlet cam follower bearing failure that wrecked a lot of the top end) about two years ago. 2005 640A.
Before the swap, the bike would "walk" across the garage on fast idle.
After the swap, the bike would still "walk" across the garage on fast idle, but I thought it was smoother whilst actually riding it.
Shortly after the first top end rebuild, I had an exhaust follower snap that totally destroyed the top end and required a total engine dis-assembly (coolant through motor). I believe the engine rebuild (by a very good KTM mechanic) resulted in a smoother bike than the piston alone.
So, my summary: If you need a new piston go the Wossner route, but I don't think it's worth the cost and hassle on it's own. YMMV