i have a 06 trx450er that i bought used i did a full oil and filter change. Took it for a test trip up north and after only a few miles of riding it lost all of its oil in the window. it didnt smoke one bit and it inst leaking out all over itself. it does bump start and runs with no issue and while running does show oil in the window once engine is not running all oil is gone. I took the top end off once i got home and nothing looked out of place nothing looks bad. Any suggestions any thoughts would be helpful.