My buddy that I ride with regularly purchased a 97 KX5 about a month ago.It's in pretty decent shape and came with a few extras....one being an extra cylinder that was freshly replated to STD bore.We don't know who did the plating,but there were ALOT of pits in it,some fairly large.There is also a number stamped on it,not something the factory would've stamped(so we think). So he sent it out to PowerSeal for it to get re-replated.They called him and told him they would need to go to 86.5mm to clean it up..."ok no problem,do whatever you have to,to make it right" my buddy says.
He gets the jug back with a new Wossner...piston/cylinder clearance is 3.5thou.Gets it running the other day,only to find the head nuts leaking.Pull it apart after 10 mins running time,and 1st thing he noticed was two scrapes on either side of the exhaust ports...possibly from being too tight,or getting too hot from the bad head gasket.After lapping the the cylinder today,he found ALOT of pits/porosity on the surface....ALOT,not big pits,but a severe amount of tiny ones...like the size of a pen tip.
So we started wondering if that number stamped on the jug is some sort of REJECT/DEFECT #.
If the porosity is really severe enough in the casting....could it cause some crazy expanding of the cylinder itself,as it heats up?...we believe it could.Has anyone ever seen or heard of defective cylinders due to porosity/casting defects?
Would love to hear some thoughts on this.
