By: ThaiDesign (offline) Friday, 23 December 2011 @ 08:14 AM ICT
Quote by: Thanin
I have a Honda NSR150, never had any serious problems but now every 2 to 3 months the Honda shop says that the crankshaft bearings are leaking...
With bearings leaking I assume you mean the crankshaft seals... Bearings are not designed to stop oil or gas to escape.
Lots of things can be the source of your problem with the crankshaft seals, one, and the most common now-a-days is that the oil seals of “old” two-stroke engines are not made to tolerate fuel that contains a percentage of ethanol or alcohol.
The ethanol-seals problem isn't an issue in four-stroke engines and therefore a good amount of seals used in the automotive industry are still incapable of dealing with fuels containing ethanol.