After deciding to split the engine type out of the frame/rack mount forums and into their own separate 2/4 stroke forums, we (the mods) have been busy, going back through all the posts in the two mount forums, moving the appropriate threads into the correct forum.
Sometimes, we've moved a thread into the wrong location, and we have to move it back, or move it to the other engine forum. Things have settled down now, so, unless a new thread is put in the wrong forum by the original poster, the forums should stay pretty stable.