ok I just bought another 400ex and this has me stumped? the guy I bought it off of said there was a recent top end done. didn’t say much else about it? but heres the problem the quad only smoke here and there? very little on start up but when its warmed up it will smoke out of nowhere? its blue! I put new valve seals in it thinking it was that? but still doing it? do you think it might be a head not torqued down right? no smoke on wot either so I know its not rings? WTH is going on? any help would be great? the quad runs, starts and idles great?