These prevent spitting A Shim out under higher boost, Not really needed on the stage 1 or the stage 2 turbo kits on the Wildcat XX, but we do recommend them on stage 2 YXZ And on all the stage 3 turbo systems. The Yamaha YXZ is constantly shifting and potentially hitting the Rev limiter, causing valve flutter. We do have a reflash for the YXZ, that will raise the Rev limiter and help prevent this.
Due to the notorious bucket wear issues on the YXZ, BC (Brian Crower) only offers shim in buckets with DLC coating. Requires BC spring/retainer kit BC0950B in order to use. Made from aerospace grade, 4140 chromoly steel alloy and completely CNC machined from heat-treated billet round bar. Heavy-duty wall thickness eliminates distortion and cam face depression, while reducing overall weight from non-critical stress areas. Nitrided and polished to a surface hardness of 60RC for minimal wear. Provides lower friction with cam lobes and cylinder head lifter bores for improved durability.