The Trask Performance CheckM8 transmission top cover helps reduce some of the causes by relieving excess crankcase pressure via a one-way Boysen valve

01-17 (NOW) Twin Cam & S&S T-Series engines

SuperLow: 2011–2019

4V for best performance throughout their life

Fits: 01-17 Twin Cam

HeinzBikes Performance Derby Cover – Sort TwinCam 90‑17 TURN SIGNALS FAIRING The Trask Performance CheckM8 transmissionHeinzBikes Performance Derby Cover Black Fits: Harley Davidson TwinCam (19902017) Give your Harley a raw and complete look with this Performance Derby Cover from German HeinzBikes. Designed to both look sharp and perform better than the standard cover, this is a must have for those who care about both performance and style. Features and benefits: CNC milled billet aluminum extremely strong and precisely machined Black Black Pearl Gloss finish high