Hi, first time poster here.
I have a 2001 sportsman 500 HO. Long story short, I changed the oil, rode it about 1/4mile, started makeing a clacking noise, turned around to go home at about 20mph, got 1/2way and the motor siezed up. I tried to crank it, it moved but not much and I didn't want to push it.
Trailered it home and took the oil filter off, no oil had flowed through the motor. I figured out the oil problem, but it won't run now. What kind of repairs am I looking at here. Can I just replace the rings? Do I have to get it honed or bored out? Does this cylinder have a removable sleeve (like KTM's) or is it a solid casting? If I have to bore it, how large can I go and where do I get parts (if I got to spend the money anyway, might as well make it as bigger and faster). I don't want to sink a furtune into this thing, I have other toys to appease as well. Any help will be appr.
Thanks

 

Hey sorry to hear your motor seized up. To see what you will need to replace you will need to tear the motor apart. If the piston is seized you will need to have it bored and will need a new piston and rings. Also you would need to check the connecting rod and crank bearings to make sure there ok.


Hope this helps

Nez

 

Thanks for the quick reply. If I need to bore the cylinder and get new piston and rings, do you have to get the head machined as well? How can you tell if the connecting rod is OK, will it be apparent that it needs replaced? How can you tell if the valves and valve seats are OK? Sorry for all the questions, I like to know what I'm getting into before I start. Any special tools that you can think of?

 

Sounds like you lost the prime on the oil pump after changing the oil (or you forgot to put the oil back in [img]i/expressions/face-icon-small-smile.gif[/img]). Same thing happened to a friend of mine on his 2001. Didn't go as far locking up but the thing was really knocking. He got away with a new cylinder, piston and rings. Still waiting for parts though, the cylinder was on backorder through Polaris.

You will have to pull the engine and tear it down. Only special tool I can think of for tear down/removal is a puller for the clutch. Chances are your top end (head and camshaft) are O.K. and if you damaged the mains or rod bearings it will be pretty obvious. Most likely you trashed the cylinder and piston, probably past the point of machining. If that is all that is damaged your probably looking at around $500.00 to get it running again.

Good luck.

 

Not to hyjack his post but how does this happen? The oil pump doesn't pick the oil back up right away? What should be done to avoid the pump loosing it's prime? I've never changed the oil in our SP700 and Scrambler since they are fairly new to us.

 

That's exaclty what happened, I lost prime to the oil pump. How do you prevent that? I followed the instructions in the manual and it said nothing about the pump loosing it's prime. Is that something Polaris left out on purpose to sell more aftermarket parts?

 

My theory would be that when you are draining the oil the oil that is in the suction tube of the pump drains back also. When you crank the engine over the pump sucks air (cavitates) and loses it's prime. Why this would happen with what I think should be a positive displacement pump I do not know. Maybe an engineer can explain better.

What my friend was told to do to re-prime the pump was to clamp off the return line back to the reservoir momentarily and start the engine. That worked well but unfortunately it was too late! The cylinder had already been damaged.

 

Thanks tbg
I know this, I will never take that banjo fitting off again, nor will I ever drain the sump. From now on, I will drain the tank, change the filter, fill it up and call it a day. Unfortunatly, I think it is too late for me as well, I see an engine rebuild in my future. I think it is sad that Polaris couldn't even warn you that this is a possibility.

 

One more question. I took out the plug, put some oil in the cylinder and was able to free the piston quite easily. I ran it up a down several times and it seems to move normally. Will I risk causeing more damage if I start it up? Assuming it does start, could I ride it like that without the rebuild? Opps I quess that was 2 more questions.

 

that wouldnt be to safe, it might have just broke free but the chances of it locking up again without it being checked out are pretty high. you might have put the wrong oil in it too. read your owners manual and see what weight oil is preferred. could have bad rings or a bent rod too.