So i got the impellor (turbine) off of my honda gx50, only to discover (to my horror) that the crankshaft is not the 1/1/4x5/8 keyed shaft that we all know and love. Instead the shaft is some smaller diameter threaded nonsense that makes me slightly ill when i look at it. Basically my question is does anyone have any experience replacing a gx50 crankshaft, and is the cost of the replacement crankshaft worth it. (I bought the engine used off of a waterpump for $50). If the cost of replacing the whole crankshaft is rediculous, are there any other avenues i can take that still render the engine useful for a motored bicycle? or am i looking at motorized box of spare parts?