One of the Chinese crankshaft ball-bearings on my engine seized and fried. In disassembling the engine to remove it, I noticed that there are are 4 identical size ball-bearings, 2 on the crankshaft and 2 on the transmission shaft. The two ball-bearings on the transmission shaft are sealed/shielded (dust covers) on both sides, while the two on the crankshaft are open (unsealed/unshielded) on the crankcase side. I assume the crankshaft bearings are unshielded so that fuel can get into the bearings in order to continually lubricate & cool them.

The higher-performance Japanese replacement bearings I purchased are sealed on both sides, but I was able to easily pop off one of the shields so the balls are exposed. Does anyone see any hazard in using these bearings as modified?

Thanks
Joe