i had that happen to me on the street. was changing my oil on my 97 gix. when ppl came up to me and ask me to help them. i got side track. i put the back in but never tighten. then i was out riding and i stop at a light and all of a sudden a cloud of smoke past me by i was like
then i look and the oil was coming out . ever since then i either put it in and tighten it or leave it out till i come back then put it in and tighten it.