2004 700 motor locked up

Leardriver · Dec 3, 2011

Hi all!

I was riding down a road about 2 miles into a slow ride, at about 25 mph. 700 RMK VES, all original and stock.

Machine had warmed up a bunch before being unloaded, and was completely warm. It started and ran perfectly. It has 900 miles since new. A real creampuff. Conservative jetting, and no changes since it was born.

It locks up solid with no warning. No det flash. I can't pull the rope, use the e-start, or move the crank by hand by spinning the primary clutch. After 20 minutes, I can move it. It starts again but locks again after a few seconds. Piston seizure, right?

I tow it out, get it home, and take the head off, expecting to see bad things. The plugs looked chocolately good, no deto marks anywhere. No scored piston or cylinder. It looked perfect. Compression is 120 per side at 6,000 feet. Oil line with VES gold are full, and there is the right amount of oil on the cylinder walls. No old gas, it was flushed right to the carb bowls within the last month, and started and run plenty before today.

Puzzled, I put it back together. It start up perfectly, idles like new for 20 seconds, and stops and locks up again. I take the head off, still looks perfect.

I fully expected some freaky top end problem, but I don't see it. The exhaust valves haven't hit anything, the clutch isn't loose like a crank problem.

What am I missing? I hate to take it apart further. My repair budget is somewhere near zero.

Jay · Dec 3, 2011

Did the water pump belt break or come off? The belt drives the waterpump and the oil pump, I had a similar experience once. If not I'm thinking a crank bearing failed.

X2Freeride · Dec 4, 2011

Bad crank bearing. As soon as it gets hot it locks up.

Leardriver · Dec 4, 2011

I am suspicious about that as well. After all, the machine had less than 1,000 easy miles on it, and couldn't reasonably be expected to last any longer.

Is there a test for it? Even cold, it will idle with no abnormal noise, and seize up in 10 seconds or so. No heat has had time to take effect.

Vertical Asshauler · Dec 5, 2011

Almost garenteed its a crank problem. Pull the reed blocks out and look at both rods and bearings for blueing or discoloration. Could be a main bearing also.

Skeeter2010 · Dec 5, 2011

What about checking the recoil and stator just to make sure nothing is bound up or the starter. What does the motor sound like?

Leardriver · Dec 5, 2011

The motor makes normal sounds when idling prior to lock-up. No metallic sounds. I thought about the belt also. I will take the recoil housing off and look.

I will pull the reed blocks out and see what I can see. I just hate to tear apart a machine that still seems new.

sled_guy · Dec 5, 2011

Crank bearing.

What oil do you use? Where do you store it in the off season?

Either one or more of the ball bearings in one of the crank bearings is pitted/rusted/damaged, or more likely, the little finger spacer that holds the individual ball bearings apart has come apart. It runs fine until the bearings drop in to a certain position and then it seizes. Sitting, wiggling, cooling down, etc lets the bearings free up and then repeat.

If it happens enough you eventually spin the bearing in the case.

sled_guy

Leardriver · Dec 5, 2011

I agree with the diagnosis, just was hoping for magic words of hope.

The machine is stored at home, dry Denver climate, started once a month during the summer, using Polaris VES gold, and manually holding the oil lever at a higher lever to drown it in oil.

So, when it's torn down, does it need a crank rebuild, new bearing put on, line bore cases, or what sort of repair is proper to make it last on its second life?

mitchellsled87 · Dec 5, 2011

How easy is it for the ball bearings to rust, or get pitted? Because i rebuilt my snowmobile this summer and left some coolant down in the crank case for a few months, and then found out about the drain plugs later on and drained it out and sprayed some brake cleaner in there to dry it out. So do you guys think it'll be rusted, it starts just fine with nothing wrong. Sorry for taking over your thread.

sled_guy · Dec 5, 2011

When you pull it down, if the cases aren't hurt then they won't need line bored. I wouldn't be surprised if the crank just needs the one bearing that is having issues, a good crank guy can tell you that. The 700s really are pretty bullet proof so unless it got moisture or somehthing in there it probably was a defective bearing from the factory.

mitchellsled87, if you let coolants stand in the bottom over the summer high enough to bathe the bearings then you have damaged them. I had the exact same thing happen on a 600RMK a couple of years ago, leaking basegasket I didn't know about so it had coolant in the bottom through the summer. I started it in the fall with a bath of premix and it made it about 10 miles in to my first ride.

sled_guy

Skeeter2010 · Dec 5, 2011

Leardriver said:
The motor makes normal sounds when idling prior to lock-up. No metallic sounds. I thought about the belt also. I will take the recoil housing off and look.

I will pull the reed blocks out and see what I can see. I just hate to tear apart a machine that still seems new.

When the motor stops running do you leave it set for 20 min and than it is free and moves? or do you rock it back and forth and it eventully frees up enough to spin?

Leardriver · Dec 5, 2011

I may have let a little coolant get into the bottom when I took the head off to be milled this summer, then.put it back on 3 days later. I don't think it drowned in coolant, but a little may have trickled down during dissasembly.
Bummer.

Skeeter, I can free up the engine instantly. It doesn't seem to be heat related at all.

I have the engine almost out, but am stuck without a clutch puller. I can't get the electric start motor off with the clutch on. I'm sure if I had better technique, it would be out.

Anyone have a puller on the SE side?

Skeeter2010 · Dec 5, 2011

I have pulled primary clutchs with two pry bars and a
oxy/acetylene torch but its a 2 person job with a large tip
I know it's not ideal but it does work in a pinch.
Keep us informed on what you find

Leardriver · Dec 5, 2011

Apparently the threads for the puller are 3/4-16. I may go buy a bolt and get a skinny 1/4 drive socket extension of the exact size to go in the hole, making my own super awesome clutch puller.

mitchellsled87 · Dec 6, 2011

sled_guy, there was only about a inch or so of coolant, maybe a little less than a inch of coolant, but it was only in there for about 2 months at most. I just hope that they aren't damaged, i heard that it takes more than 2 months two make em rust.

sled_guy · Dec 6, 2011

Leardriver, I don't think your issue was coolant.

mitchellsled87, time will tell

I don't know how caustic coolant is on them.

sled_guy

Leardriver · Dec 6, 2011

Well, my home made puller seems like it should be working, but it isn't.

Anybody know the dimensions of the clutch puller tip? I would think that it was made that skinny for a reason.

I ground down a 1/4 inch socket extension, and am pressing on it with a 3/4-16 bolt, but it won't pop off, even after some time with a heat gun on the outside to expand the clutch a bit.

skibreeze · Dec 6, 2011

Pulling clutches can be a bear, I'd use the proper puller. Vickery can't be too far from you.

sled_guy · Dec 6, 2011

The puller goes down through the threads in the crank end and bottoms out in the hole. It's rounded off to fit in to the curve cut in the bottom of the bolt hole.

sled_guy

2004 700 motor locked up

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