Help, my RM250T is emptying it's crankcase !!....

[kevwrx]

Rode my RM250T today, (first time I've ridden it, and first ride of a 250T since 1980 !)
Anyways, it has decided to empty the contents of the crankcase (through the breather hose) in a five minute ride.
I recon it probably lost around 200 to 300 cc of oil in 5 minutes, all over the back  wheel.
Does anyone know why this would happen ??
Kind regards
Kev

[mx250]

More like you have emptied the gear box oil.

Means the gear box as been pressurised most probably by a leaking main seal on the crankshaft.

Could be a blocked or partially blocked breather - spinning gears can cause pressure in gearbox with windage from spinning gears and clutchs.

[Doc]

yeah I'd be thinking rh crankseal or the inner o'ring on the shaft has split but for the fact whenever I have had these blow they suck crankcase oil and blow lots of smoke and foul up. Sure sounds like an excess of crankcase pressure tho. Only thing I haven't had happen was the centre case gasket leak in the crank area..maybe this could do it but again I feel it would suck not blow..guessing sorry..never seen this specific prob on any 2 smoker    the gearbox isn't overfull is it?

[gerpster]

Yeh I was thinking over full gearbox or did you use some of that new fangled oil full detergents and stuff?