Gilles ACMA Top Yoke Lock Nut BRAND NEW Black This will fit: Yamaha YZF R1 2004-2006 Gilles Tooling ACM Alu is derived straight from our popular patented self-locking titanium ACM safety lock nut. In common with its sister product, it has the easy to use pin-interlock system to prevent it from loosening. NB………ACMA Is designed solely for use as top yoke nut. Do not use on the rear axle or swing arm axle!.