cylinder shots, need some help

[meatball]

I popped the head of the 650 to replace a headgasket I though leaking due to what appeared to be water in the exhaust manifold. When I did, I found something I wasnt really expecting or wanting. As a background, this ski was mostly garage kept, rode all last season, and ran fine all last season, except it overheated once due to a clogged coolant system, and the fuel filter clogged it and leaned it.

This motor has not been run since it was fogged, and I shot juice in it til it quit at that time.

This is the front cylinder dome.
front cyl dome


head off


front cylinder scoring



The pic below shows the worst score. You can feel it with your fingernail.
front cylinder


rear cylinder


rear cyl dome


What exactly do I need to do from here? Anything? Preventative? I had no problems with knocking or performance at all last season, starting, nothing. There seems to be no play in the crank, but I only checked by pushing on the pistons while rotating the coupler. Do I need to do anything? And what could be the cause?

 

[Mouthfulloflake]

that scoring is pretty normal for water ingestion, that worst one maybe from some metal ingestion, but if it was running like that, it will run again.

get a new head gasket, and ride it some more.

 

[SkiDaddy]

From the pitting in the front cylinder head & the scoring I'd guess the rod needle bearings are breaking up and pieces of them are going thru that cylinder. I'd recommend you pull the cylinder off & check it before it grenades......:bigeyes:

 

[#ZERO]

Yep...if you went to the trouble to pull the head you may just want to pull the cylinder and bore it to the next size and check for further problems.

Did you do a compression test before you pulled the head?

 

[SUPERTUNE]

Hey guys! It's an old 650 motor, and yes it has a milled pro-tec head on it. Lap head and use a new OEM headgasket and run till it blows, then build you a 701 motor. Looks like trash from water ingestion...

 

[meatball]

Really, the head is milled? Makes sense, the topend was done in 96 and it sat garge kept since them. I didnt check the compression before this, but at season begginning it was at 150/150 abouts. I was hoping to sell it (already have my 701 ski in the works) so I guess I'll check the crank because the one gouge does seem like metal. Not sure what I'm going to do at this point, but thanks a lot guys! (I figured the regular stuff was water ingestion)

I guess I'll add there are absolutely no marks in the pistons. I'm not sure if they are OEM or not when he did the topend.