Hot Rods – Dirt Bike, including connecting rod kits, crankshaft assemblies, bottom end kits, counter balancer kits, output shaft kits, transmission and engine bearing kits and water pump kits for bikes like the Yamaha YZ125 and YZ250, Honda CR250R and CRF450R, Kawasaki KX100 and KTM 125 SX. A motocross or off-road engine spends its life at revs a street bike never sees, and the bottom end is the part that quietly runs out of hours. A rod bearing that goes from tight to noisy takes the crank, the cases and sometimes the transmission with it, which turns a scheduled bottom end rebuild into a whole new engine. Hot Rods cranks and rods are forged and ground for that duty cycle, with plated pins and bearings selected for high rpm and hard hits rather than showroom mileage. Rebuilding on a schedule keeps the power delivery crisp, stops the vibration that beats up mounts and radiators, and keeps a good bike in the gate instead of on the stand. Kits are model and year specific, and two-stroke and four-stroke parts do not cross over. Send us your year, make and model and we will confirm the correct kit before you order.