The individual that I bought the rebuild kit from also rebuilds them for a fee of course. He says to get an electric skillet and lay the bearing on there and get it hot. Then use pliers to slide it on the shaft. No hammering required. I may be doing that this weekend. Which 56 gearbox do you have, A or L series? I got an L series with the A12 motor I purchased. Bought the motor because it had hitachi carbs with intake and GX head and GX exhaust header which will all be going on the A15 motor I am building. Dont have much use for the A12 motor or 56L box at this time.