Very high 12:1 compression ratio. Racing only. Standard 3-1/2" bore domed pistons. Includes forged pistons Hastings rings wrist pins and circlips. Note: See 908655 for a replacement Hastings piston ring set. Note: Oversizes are not available. 04-22 XL1200 04-10 Buell XB12R/S (NU)