Hi there i bought a 93 FXRP the bike sat for year and a half and wasnt runed even once.

I did an oil change and started the bike start without any hasle but after 1 min runing idle
oil in oil tank is overfilled and looks like its gonna spill from the filling cap (oil level is getting up to fillip cap on top of the tank).
Engine is runing good no noises from valves or somthing.

What could be the problem ?

 

There was a bunch of oil down inside the crankcase that got pumped back into the tank when you started it up.

In and of itself, not a problem.

There is a checkvalve in the oil system that is designed to prevent gravity from pulling oil into the crankcase when the bike sits. Those are prone to getting ishy over time.

Before changing the oil, run the bike for a few minutes to make sure any oil in the case is returned to the tank.

Keep an eye on it. Odds are that the amount of oil getting pulled into the case isn't enough to worry about over reasonably short (week or two, lets say) time frames. If you get more sumping than that, then you might need to look at correcting the checkvalve, but I wouldn't assume that is the case just yet.

 

Oil sumping for sitting so long. Just drain some oil from the tank down to the appropriate level, and you'd be good to go.

 

If i understand correctly so while the bike sat oil drained to crankcase and when i drained the oil from the engine that oil stayed on the crankcase and when i filled oil and replaced the oil filter and runned the engine the oil from the crankcase returned to the oil tank and i ended up with too much oil in the tank.
Am i right wrong ?

 

You're exactly right.

 

You got it. The sumping is normal and should stop, but keep an eye on it like Omaha said.

 

Exactly right. Current Sportsters tell us in the owners manual to do exactly what 0maha suggests, as they have a similar problem, although for different reasons.

 

Thanks for your quick and informative responses.

One more question for next time is it OK to start up a bike that sat for a year and a half with that old oil for few minutes to check if oil is going back to the oil tank ?

 

Best thing to do in a situation like that is to pull the plugs and spin the motor over for 15 seconds or so. Give the starter motor a few seconds to rest, then repeat. Do that three or four times. You want to get the oil circulated a bit before starting her up.

There's no harm in changing out the oil at that point, but personally, I'm lazy and I'd just put the plugs back in and start it.

 

Or you can take the return line off and run it to a drain pan.
Fill the oil bag.
Start the motor and when you see clean oil coming out of the return line stop the motor and refill the oil bag.