HOT ROD SLED SHOP- IMPROVED FOR 2018- QRS SHIM KIT : FITS 2008-2019 Ski-doo XP,XS,XR, REV GEN4 COMES WITH 4 EACH OF .020" BEARING SHIMS THAT ALLOW YOU TO SET THE PROPER OFFSET IN YOUR SECONDARY CLUTCH. . Most 0f these machines need the full .080" stack which is 2mm offset. The 1.5mm & 2mm shim kits don't cut the mustard anymore. That black belt residue all over your secondary clutch and cover is from the misalignment of the factory clutches-especially under load. Ski-doo has all new alignment specs. for 2019 and they are closer to what we found ideal for 850 clutch alignment. Check out our new alignment bar with 2019 updated printed specs. right on it. This QRS shim kit has 4 -.020" SHIMS to put behind the chaincase bearing and the tower bearing to evenly space the jackshaft out in smaller, more precise increments than ever before. It allows you to shim the jackshaft much closer to proper alignment, and proper clutch offset. . This kit includes 4- bearing tower shims, 4- chaincase bearing shims, and complete instructions and alignment specifications. The QRS shim kit includes alignment specs. and instructions that when combined with a modified poly motor mount, HRSS motor mount shim kit, and the HRSS QRS shim kit result in a much stiffer mount system , longer Z measurement, and proper offset at an affordable price (NOT $200+ LOADER KITS. The updated Ski-doo mount kits with this 2mm offset stack reduces belt heat and gets alignment infinitely better than any other setup we've tried. Check out our new alignment bar and polyurethane motor mount for the REV GEN4 also.