spark plug problem

[Groomsy]

This has only happened once, and i hope it never happens again. I was on my '04 EX riding down the road(yeah i know, the road) and the engine decompressed, leaving me sitting on my cell hone to get my truck to me. Once i got it back home i discovered the spark plug was blown out of the head. The threads on the plug and in the head had no visible damage tha i could see. Any idea what could have caused this to happen?

[Doibugu2]

they do work them selves loose sometimes. Just something routine matenatince should catch.

[Groomsy]

alright thanx i didn't know if this was a common problem among the 400's or not just wondering if anyone else had experienced this

[underpowered]

never had it happen on a400, but have seen it on an old polaris trail boss. not a common problems, but it can work itself loose. jsut put it back in and tighten it down, not to tight, they are easy to strip.