WhatApart Drive Chain (Primary) compatible with TrailMaster Mini XRX and Mini XRS, part #14‑1103‑00) is the primary/upper drive chain used on those small go‑kart models. It's a roller chain (420 size) with about 48 links/pins that runs next to the engine between the engine's clutch and the jackshaft/front sprocket, transferring engine power into the rest of the drivetrain. The chain usually includes a master link for installation and is replaced when worn, stretched, or damaged to maintain smooth, reliable power transmission.