Check the cases carefully at the top and also at the front and bottom. If you haven't broken or cracked one consider yourself lucky.The piston skirt may have broken in intervals and finally enough to stop it dead in its tracks I've seen dozens of engines like this over the years. My two cents is no matter how many times you may flush the bottom end out I wouldn't trust just doing a top end. Skirt breaking can come from too much clearance,needing a new piston way before it shattered the skirt,or sometimes just the nature of cast pistons themselves.

 

Ok. Also, how much movement is allowed in the rod to crank bearing? Yes I may end up pulling the engine and if I turn it upside down and blow air and use brake clean I bet it would clean up okay. How hard is engine removal?

 

After seeing the piston I'm surprised the cylinder isn't worse than it is.

 

NO up and down play allowed on the rod itself.. A little side to side play is acceptable. If any crank bearing feels rough or binds as you slowly turn the rod,I'd have a rod kit installed and new crank bearings and seals. Of course that involves the water pump seals,bearing,etc. Basically you'd be rebuilding the entire engine including the top end. The way it looks,if mine that's the way I'd go after doing so many of these. Plus I've seen my share of top ends only that I bored cylinders out for people for take out that I warned on checking bottom ends that ended up back at the shop later when lower rod bearings starts spitting bearings and took out their new top end. That's the reson why I would not guarantee a top end only If I did all the work at the shop.

 

Jumbofrank- I was surprised as well, I can hardly feel any roughness with my finger, even over the scored areas.
OPT- If I were to pull the engine it would probably turn into a full rebuild, basically. I am working on the math of parts to figure up about what the cost may be. Mostly seals, maybe a bottom end kit would have everything? Rick has a set with new bored jug, piston kit, and gaskets for 273. Not too bad depending on what my cost is for a bore job here.

 

Would that manual have the info for engine removal and rebuilding? Easily worth 5 bucks if it does.

 

That's the thing about some manuals as they jump from one section to another without clear cut ways of doing some things.They expect you to already be a mechanic and know how to tear an engine out without having to go into detail.. Obviously the things you have to remove are the clutch cover,clutches,backing plate,recoil,flywheel and it's easier to just remove the stator plate and leave it on the floor board.Always MARK the stator plate to the engine case even if you have a mark on the plate and engine. Carb,air box,exhaust have to be removed. Front motor mount,top motor mount,rear mount nut. Take pics if you're not sure on things for reassembly. The engine can then be wiggled around and slid out the left side.Once on the work bench is where the manual really comes into play on the different areas of the engine.That's where it's more specific on critical parts such as water pump seals as there are two different ones,the counter balncer and how to remove it,plus the mark on the c/b sprocket and the crank sprocket to get both in time with each other. Yes the manual is easily worth 5 bucks on one job alone.That's why I've been pushing them on people for years.. But there are still some out there that want you to tell them every little procedure on how to do things. That's when I throw this at em..Polaris ATV Service Manuals PDF Download

 

Figured so. Probably finish tallying up costs and see what it'll be to fix it right. Maybe have to tear it apart first and see what is broken or needs replaced. Definitely adding the cost of the manual in there. 😂

 

I noticed when removing the cylinder that the top mount behind the head had separated. The rubber part was fine, but between the rubber part and the head, it had come apart. May be why it shakes so bad.