I have a newer 2003 bought it in may of this year and i really havn't ridden it very much so its been sitting alot lately. And its never used oil until i've been letting it sit i went to check the oil level today because i was gonna go ride with some kids and theres no oil on the dipstick. Why would it all of a sudden lose oil from just sitting. Its not leaking it.

 

The oil has ran down into the engine. The longer they sit the more it happens. If you know there is oil in it, start it, let it run a couple minutes shut it off. Recheck it then.

 

The something like that happened to me TODAY! I had checked the oil a couple of days ago, and I went for about a 2 hour ride today. I get home, check my oil, and there is NOTHING on the dipstick! I am pretty panicked. I put about 300 mL in, and start it up for a minute. Then I check the dipstick again, and it's way over full!

What I figure happened is that while the bike was bouncing around on the trailer, the oil got shaken down into the crankcase (which is pretty much what happens when the bike sits for a long time). When you start it up, the oil pump will bring it back up to the tank, and give you a correct reading.