Well this sucks.

Today tried to go riding. Hour drive to wear we were going, my camp. Got there, started my sled unloaded it, then drove it down to the pole builing to put some new carbides on. 100 feet. from there i drove it back up to my camp and it was running like it had a fouled plug. So i took both plugs out and they looked perfect. So im thinking wtf is going on, maybe its just a little loaded up. So i take it back and forth accross the lake and its still running bad. Pull plugs again and still fine. Go and get my gear on and we all take off across the lake again when i just lose all power and it shuts off on me. It would not budge either when i pulled on the recoil. So i got towed back to my camp and loaded it on the trailer and let it sit. Tried it again and it was free but didnt want to try and keep pulling it.

What could be the problem? I thought crank bearings at first because it shitted out on me like this last year, but it is free now. I'm thinking i might have cold seized it but i remember looking down at my temperature guage and it was in the middle where it is.

What can i do to look at it? Pull the head?

The sons 03 700 SKS had somewhat the same thing happen two weeks ago. He was riding along at 30 mph when it just stopped dead. He couldn't pull it over either. We loaded it up and brought into the shop. Once home, I could turn the sled over with the clutch by hand.

Three hours later we found this:

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The lower cage that keeps the ball bearings separated started getting chewed up. The piston also took a beating along with the cylinder and head. We just bought the sled used this September and I don't know the cause? It is possible that the previous onwer didn't fog, and the PTO bearing took a dive? The outcome, bearing upgrade to double roller bearing, re-nicksil pto cylinder, two new pistons,rings and total gasket set. I could of gotten by with one piston, but since we were that far into it, go all the way. BTW sled has less than 2000 miles.

IMHO, these 700 and 800 are not set to get enough oil. I've set all of mine up a few turns, so they are just past the mark at idle, and they use just a little more oil than before. Valves are cleaner too. Cheap insurance if you ask me. Now that I open my big mouth, I hope they don't let me down now...

I just returned from Indy Specialty with the crank and crank case upgrade to larger PTO bearing. He figured that either the oil pump was failing or good chance the previous owner didn't fog? The fun never stops......even when we have no snow to ride...
Mark

the same thing happened to me last year, my oil pump went bad and i scorched a cylinder and piston, after letting it sit i could also pull it over by hand so i would look and see what the pistons like

By the looks of your piston markcp, some antifreeze got into your cylinder. When it makes marks like that on the piston usually from anti-freeze getting in, antifreeze can't burn, so you probably had no more good O-rings for the cylinder head. As for the crankshaft looks like that rivet that is right at the back of the starter cover broke off and messed up everything in there, my buddy used to have a 2003 XC 700, same engine as your sons SKS 700. The rivet been coming off and into the starter cover.....Check to see if your rivet is missing now, it's right at the back of the starter cover on the top....If it ain't there, then that's why the crank went...

I checked the rivets around the pull chord and rewind cover, with everything is intact.

From how I see it:
The PTO end bearing had failure. The race that holds the ball bearings apart started grinding up. The small barbell like rivets that holds the two sides of the race together also came apart. One of the race's rivets made its way up the piston, and beat the day lights out of the piston top and head. You can see score marks up the cylinder wall and also down the piston. The dents in the piston top and head match those of the rivets from the bearing race. As mentioned in previous posts, the sled was used, and we believe the previous owner didn't fog the motor. When we picked the sled up in September, it was first time started since last spring. We didn't get the blue smoke pouring out like a sled that has been fogged. Three hundred miles this winter, and the rust won the battle over the bearing. We are now waiting for the PTO side cylinder to come back from a hone and replating job.

All that after you spent $ on clutch parts to make it perform better as well!!! I would also say bearinbg failure, whether related to not fogging it that is hard to say. How was it running with the changes you did? How about your 800?

We love the changes to both sleds Pockets. It has been real depressing with our snow. It has been unridable for all but a few days here and there, but now they talk maybe 10" over night? Once I get his 700 buttoned up, the 800 is going to get pulled and the larger bearing upgrade will be put in that also. I found it will be less expensive to upgrade before the metal starts grinding things up? The price per mile this winter has been on the "expensive" side.
Mark
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Can I ask where you guys get those small windshields from? and do you have the part Numbers?

Really? Valves are cleaner?

How much did it cost to get the crank rebuilt by Dan at Indy Specialties. Did you redo all the bearings and mods to the cases? I have one I need fixed too. Heard great things about him.

We had the larger crank bearing upgrade done, complete gasket and seal set, complete 2 piston set, one cylinder honed and crank checked for true for $713.00. The crank side bearings had to be cut off, so a little more labor charge on that end. I had everything pulled from sled and took him the split case and crank. Turn around was about a week. Once I get my cylinder back from re-plate in Wisconsin, it will be ready to run. My 03 800 SKS will be getting the bearing upgrade from Dan once I have time to pull it apart. Mark