Hey guys I have an older '91' evo it has been neglected the last few yrs for lack of a good place to tear it down (my lady wont let me bring it in the house) it needs new rotor, to deal with that I got a deep cycle battery , it also has a busted spring in the tranny, so I have to toe it down before the up-shift... it goes on and on and I have most all the parts to make the repairs, but with all this I started riding less and less..

All that said... after being parked a few months, the first start-up it pukes oil out the crankcase oil breather... thats the problem I dont know what to repair to stop this, or how serious it is...
I am finally getting a place to do the work, top end rotor and shifting prob but I dont what repair is needed in the lower end or how serious this is..

ANYONE???

 

My Evo did this to me if I didn't start it for a few weeks.
Ok there is a check valve with a spring that holds the oil into the oil tank below the seat from draining back into the engine. So after awhile the oil does leak past the check valve and collect into the lower case of the engine. Usualy getting above the vent tube that next to the oil pump. So when the motor starts it build pressure back pressure in the lower cases and blows the oil out of the vent line all over the bike usually. This is one of the reasons that harley when to the heads with the vents. You can raise the level of the vent tube higher and that should help. Or get a new spring for the check valve, shouldn't be very much and pretty easy to change.
Hope this helps and didn't confuse you any more.

 

WET SUMPING
One common problem that scares people is wet sumping. This is basically when you have too much oil in the bottom of the crankcase and it either blows out the breather or the flywheels throws it up on to the piston skirts and the motor smokes badly or both.

There are a couple of things that will cause this. Most of the time it is because of a check valve in the oil pump that is not seated This is very common in Harley Sportsters built before 1977 and softails fall into this group occasionally.

Usually this happens after the bike sits for an extended period of non use. On the older Sportster it usually blows a big puddle of oil out of the breather tube attached to the bottom of the cam cover. Sometimes it will smoke, sometimes not, it just depends how much oil is in the bottom of the motor. Usually if the plugs don't foul, it will clear itself out just by running the motor awhile. If it happens repeatedly at shorter and shorter intervals it is probably time for a new oil pump or at least a rebuild. The problem happens because of the oil tank being higher on the bike than the motor which causes siphoning of the oil into the engine.