had an it250k motor that was cracked just up from the base & over a large area--most of one side [RH side by memory. Was still in one piece but un-useable without surgery. Was a common problem back in the day with lot's of ideas as to 'why' i.e. frame flex on jumping--loose engine mounts--etc, or all of the above. Think people used to leave the head steady off in the end. I did wonder if a head steady with rubber bushes set into both bolt holes of the frame or the steady plate--say honda sprocket rubbers, bonded steel rubber type might help give some support but slight flex as well. Even the YZ250/360A had that on the rear top engine mount supposedly [i thought] due to frame flex. Maybe i'm wrong. Anyway my IT250K has a YZ465H motor in--that fixed it lol. Do love the 250K motor though, bullet proof, 6 speed & great to ride. Sorry for the essay, more picks when finished please. I see the DG pipe--got one from 'dirt overstock' a few years back for our yz490k & was a terrible fit out of the box which was disappointing. Thanks.