Crank seal?

[CRrider125r]

I have a 2001 cr 125 and before i went out riding i checked and filled the tranny fluid then i went out ridin and got back and it was low i checked the clutch cover for any leakage an the sprocket seal and no leakage. Then i filled it and put it in the shed and a couple days later i went out and checked and it was full. the only thing i can think of is the crank seal because it only lost fluid when i was riding. but my bike was running really good no bogs or hickups. i am so confused wouldn't it run like crap if the seal was leaking.

 

[TimberPig]

If the level was fine after it had cooled down, it was likely simply spun out of the clutch cavity in the cases, and sitting in the transmission instead. There is a good reason why you check levels when cold.

In order for the seal to be leaking, the fluid wouldn't reappear. A leaking crank seal lets the oil get burnt in the cylinder, not leak out of the clutch/tranny case into the crankcase, and back again.

 

[CRrider125r]

no i refilled it and went and checked it a couple days later and it was fine.

 

[TimberPig]

Normally a crank seal will leak vacuum, thus letting oil be sucked into the crankcase. When the engine is not running, no vacuum will be present. Try filling the bike, riding it, and checking the level. If it is consistently dropping without any external leaks, your seal is likely on its way out.

If it is leaking while sitting idle, you will find great clouds of smoke upon startup.