Hello All, I switched on my motorbike tonight and the oil cup popped out due to crankcase pressure, spilling out oil as well. The oil cap cannot be screwed back as the round plastic lines of the oil cap (dunno how they are called) have worn out. I suppose the crankcase pressure must have worn those lines by the pass of time that's why it cannot be screwed back. Is this pressure normal? What can be causing this pressure? If the crankcase breather is fine this can be something more serious that has to do with the engine? Thanks!!!
it's ok to have some air pressure pulsing in the crankcase as long as it isn't charged with oil particularly on tick-over(when engine good and hot). This is a bit 'how long's a piece of string' though as sometimes a bit of oil puffing is ok depending on conditions. It sounds like threads are possibly stripped due to previous cross-threading/overtightening and a new one will fix it. I think thread is the same for most :- Ducati '97 ST2 Engine Oil Filler Cap | eBay
