Sorry that it came down to this.Previous owner may not have known what was really wrong or could have known and just passed this problem onto someone else.Piston seizure like this could have been from low oil,wrong oil,even a neglected air filter. Problem is since it's either a Taiwanese or South Korean engine,no over size pistons kits are available that I can find. Would take a new cylinder ,piston,rings,piston pin,head gasket and base gasket. Around $335 on the piston,rings,pin,clips, new cylinder,head gasket and base gasket. I'd have the lower end looked at before you order any parts as if the rod is bad,the crank shaft assy has to be replaced and that would add more than $400 more to the parts. Dirt Cheap Yamaha & Polaris OEM Parts & Accessories – Cycle Parts Warehouse Dirt Cheap Yamaha & Polaris OEM Parts & Accessories – Cycle Parts Warehouse Really believe it looks too scored up to be able to just hone the cylinder and install a new piston kit.

 

Win some and ya lose some......Earlier this week I ordered up a new Piston, pin, rings, base and head gasket before I realized the cylinder was not honable.......I may have to put the project on hold until I recoupe some of the funds I put out.

I was thinking if I could resleeve cheap enough to a standard size sleeve, I would be able to squeeze by with a running machine. Really didnt want to get this deep and would like to not open up the bottom end if possible. All be it that would be a roll of the dice to ignore.

 

You may be able to do this. Call LA Sleeve or even this place on prices. Plated Cylinder Services | Plating Honing Repair | Piston Coating | Big Bore Kits | Motorcycles | Snowmobiles | Dirt Bikes | Rebuild | Replace | U.S. Chrome Corporation of Wisconsin Cylinder Repair Company We used LA sleeve on a lot of Ktm replating and sleeve work among a couple others,but if any of them charge close to or over 250 bucks or so,I'd just order the new cylinder and not have any doubts as to where it was resleeved to the correct size.

 

Thanks again, I will def contact them and see what kind of prices I am looking at.

 

Snapped a pic of the rod, def seems like the upper part of it got hot:

 

Yes it appears to have blued from heat.Check for ANY noticeable up and down play on the rod. A little side to side play is usually acceptable. If there is any play,the crank shaft has to be replaced as the parts list doesn't list the rod, lower bearing,crank pin separately.

 

the piston is toast but the cyl looks not as bad I would hone it out and see how it looks. just replace piston and rings if most of the scoring comes out. then figure out what caused this so it does not do it again. I would also ck out the timing chain and tensioners. while apart. they are known to jump timing when timing chain stretches

 

Ended up getting a new cylinder as it was cheaper than having the factory piece re sleeved. $210 new or $230 for a re sleeve through CA sleeve

So now I have all new OEM stuff:
Rings
Cylinder
Piston
Wrist Pin
head gasket
Base gasket

Should these new parts be plug and play or will I need to ck ring gap and piston to cylinder clearances?

 

Being that I bought the bike used, not sure I will ever know if it was neglect abuse or otherwise.

 

With new oem parts should just be a straight forward install,but I'd always check the compression ring end gaps. Should be no tighter than about .008 or what the manual says with rings installed in cylinder base.Shows clearance specs in engine section. Plus make sure you torque everything to specs.