I just did a complete motor rebuild on my son's sled which cost me around $1400. I had to replace the pistons, one cylinder, full seal kit, the lower end was split and a new oil pump added. It would of been way cheaper just to buy a used motor but I didn't want to spend say $700 and have someone else's potential problem. Your motor may just need a top end kit which you could easily do for under $700. Good luck