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Discussion Starter #1
To start off this fun day, I removed the oil drain plug and no oil came out. WTF? A few seconds later, large gobs of thick and chunky oil starts falling out. Yank the side cover and the jelly oil is stuck everywhere. Thick as in a 1/4" layer wouldn't budge when tilted, like jam. Oil smells like exhaust.

I noticed a small steel pin that was broke off from somewhere and was laying down near the water pump. Turns out it's the pin off the decompression assembly, which explains why the Grizz won't start. I ended up pulling out the decompressor lever which allowed the decompression lever pin to fall out of the camshaft. I ended up rotating the engine clockwise and counterclockwise a bit while trying to fish out the pin with a magnet. Got that issue sorted out.


Now I can't turn the crankshaft counter clockwise as normal. It'll turn 1/4 turn before coming to a sudden stop with a loud metal bang inside the engine. Turn it clockwise 1/2 turn and it'll go back counter clockwise 1/4, another 1/2 clockwise and then it'll go another 1/4 counter clockwise and so on. But, it refuses to rotate counter clockwise like it should.


I changed the timing chain. If the timing is too far off, would it prevent the engine from rotating?


What would cause the little pin to break off the decompression assembly?
 

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Sorry to hear about your trouble. We’ve got some great motor gurus that’ll be along shortly. @dezz.
 

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I’m no guru.. but I do know if your timing is way off, the piston will hit the valves. It will stop the piston from going to full top of the cylinder and prevent the crank from turning further.


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Your gonna have to pull the cylinder to see what is hitting what, and how much damage (if any) has been caused.

If the timing is off by 3 teeth (if I remember correctly) the piston will hit the valves. If you timed it to the wrong timing marks, this can cause the decompression pin to shear off.
Only a suspicion right now, but I suspect you have it timed to the wrong timing marks or it jumped timing. The piston hit the valve preventing it from opening. When the decompression pin could not slightly open the valve (that's how it works), the pin sheared off. Best guess at this moment. So t know for sure until you pull the cylinder.

I have seen the timing chain come off the lower sprocket in the case and get jammed between the sprocket and case, locking the engine up.

Oil like that means it's really, really old. So I would suspect severe wear everywhere in that engine. Hopefully I am wrong though.

There could be one of many things that is bringing up that engine solid. Right now you need to pull the cylinder to see what is going on. Any loud clanking noises in an engine is bad though....usually really bad. Either way, that cylinder has to come off.
 

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You mention that you changed the timing chain. This is just a thought but maybe when you took the chain off, the counter balancer gear moved and now it isn't timed with the crank? That could explain the loud bang inside the motor when you try to turn it.
In the picture below you can see the 2 dots on each gear are aligned which times the counter balancer with the crank.


I would investigate that before taking the cylinder off.
 

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As you said jelled gas, and then described the oil, was the grizz parked a long time after problems on the last ride?
The 1/2 turn right, then 1/4 turn left makes me think something big is in the bottom of the case, like a piston skirt. The loud bang doesn't make sense.
I would stop turning on the engine, as the bang is from something binding inside the case and probably causing extra damage.
Inspecting the gears should require turning the motor more, so is it worth the extra damage?
I would fill the case with solvent (gas) to break down the thick oil, then drain, but be careful if in a heated shop. Getting the thick oil out may let whatever is binding the crank fall to the bottom of the case.
Once the head is off you'll see the condition of the valves, and once the cyl. is off you'll get a look and feel at/of the piston and crank shaft.
Have you removed the C.V.T. cover? If not I suggest you do this too, I'm wondering if the loud noise is from the other side of the engine.
Wet-clutch shoe wear can thicken and discolor oil fast, and something wrong in the one-way can cause the turning by hand situation.
Keep us in the loop....
 

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Discussion Starter #7
This started a long time ago...

Everything ran mint before parking it. Sat for 6+ months and it would barely run with engine knock that matched RPM's. Changed oil and filter, spark plug, air filter, drained gas tank, adjusted valves, no exhaust leaks, stator and CPS working, good battery, no engine codes, compression good. Checked everything outside of engine.

Rechecked valves and they were good. Engine would turn as normal.

Sat for another 6+ months before I just did timing and oil chains, which is where I am now. The oil pump chain was loose enough to hit case, but was not wearing. New one is about 3/8" from case. Adjuster had more than half adjustment remaining with old chain and guides are like new. Replaced chain and guides anyways.

Crank rotated counter clockwise like normal before I had the issue with the decompression pin falling out of the camshaft. Now it rotates clockwise with zero binding or noise, but will not go around counter clockwise like it should.



It has only been run on the stock chain and timing, not after I changed chain. There shouldn't be anything broken from me rotating by hand, I hope?


Oil was changed when I first noticed the issue and has less than 15 minutes of use, but it is over a year old and stinks like exhaust.


Thinking back, I recall the intake valves both lifting high. Does this mean I am way off with the timing and the piston is hitting the valves like Madkawi suggests?





So, could the broken decompression pin have been my problem since the beginning? Would it effect how the engine runs, if you can get it started? Sucks that a tiny little broken pin is costing me $80+ CAD...
 

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Discussion Starter #8 (Edited)

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You mention that you changed the timing chain. This is just a thought but maybe when you took the chain off, the counter balancer gear moved and now it isn't timed with the crank? That could explain the loud bang inside the motor when you try to turn it.
In the picture below you can see the 2 dots on each gear are aligned which times the counter balancer with the crank.


I would investigate that before taking the cylinder off.
Ok, looks like I misunderstood what you meant by the "loud bang" when you try to turn the engine over. If I understand your last post correctly, the engine was able to turn over after you changed the chain? The "loud bang" is coming from the inside of the crankcase or near the top of the cylinder?
 

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x2 What these guy's have said, plus if the valves have hit the piston they could get a small bend in them so when the head is off tilt it so the inlet valves will hold(for example) gas, kerosene or similar, put a small amount on top of the valve pocket & see if it leaks thru, bent valves will lose compression.
 

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Discussion Starter #11
The bang is a solid steel on steel knock that occurs when I attempt to turn the crank counter clockwise.

Crank turned counter clockwise
Removed chains, pin on cam felt out
Replaced cam pin and chains
Crank no longer turns counter clockwise


Sounds to me like it's up towards the top end
 

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The bang is a solid steel on steel knock that occurs when I attempt to turn the crank counter clockwise.

Crank turned counter clockwise
Removed chains, pin on cam felt out
Replaced cam pin and chains
Crank no longer turns counter clockwise


Sounds to me like it's up towards the top end
Did you check that the counter balancer gear is timed with the crank gear when you put the new chain on?

If everything is already back together and filled with oil, I can understand that you don't want to take it all apart again and waste good oil and gaskets. If that's the case, taking the cylinder off is your option but you'll still need gaskets. But from what you are describing, to me sounds like it's the counter balancer that is hitting the crank. Like the video below. I'm not saying I'm right, just saying that it's a possibility.
 

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Discussion Starter #13
Did you check that the counter balancer gear is timed with the crank gear when you put the new chain on?


]
This seems to be my issue. Please tell me it's as easy as lining up the dots and I'll be good to go again?


So, would this broken decomp pin be the cause of my initial problems with 1/2 power, intermittent throttle surging, knocking and a couple backfires/coughs up through the intake after the machine sat for 6 months the first time? Or, would it be something else that's broken which caused the pin to break off?



Ridgway, I made an error in the thread title, I meant oil. Still trying to figure out how or why the oil turned to jelly. No gas, water, or antifreeze got in there.


I'm so tempted to just drop the $2500 on a rebuilt engine as this has been such a long and drawn out process.
 

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This seems to be my issue. Please tell me it's as easy as lining up the dots and I'll be good to go again?


So, would this broken decomp pin be the cause of my initial problems ...
I have an 02 Grizzly 660 and for mine:
1. When you install the drive gear, you have to align the dot on the gear with the slot for the woodruff key on the shaft.

2. While pushing the gear into place, make sure the dot on the drive gear is aligned with the dot on the balancer gear.

This would only solve the crank not turning problem though.
 

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Discussion Starter #15
Thank you very much, I hadn't aligned anything. I'll play around tomorrow.

Seeing as I already have so much stuff stripped off the ATV already (everything to do valve job, stator side nearly empty) how much farther do I have to go to remove the head so I can inspect the cylinder, piston, and rod?
 

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I would just start by checking that the shaft is timed with the balancer, then make sure the timing chain is ok and go from there. If things rotate as they did before, I don't think you will need to remove the cylinder but it wouldn't hurt to re check the valves I guess.
 

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I had my decompression pin break on me 2 years ago on my 700/843. burnt post off starter and cables.
was interminent as sometimes the pin would rotate and catch the pin in the right spot. mine broke right where the flat spot was milled into pin
 

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This started a long time ago...

Everything ran mint before parking it. Sat for 6+ months and it would barely run with engine knock that matched RPM's. Changed oil and filter, spark plug, air filter, drained gas tank, adjusted valves, no exhaust leaks, stator and CPS working, good battery, no engine codes, compression good. Checked everything outside of engine.

Rechecked valves and they were good. Engine would turn as normal.

Sat for another 6+ months before I just did timing and oil chains, which is where I am now. The oil pump chain was loose enough to hit case, but was not wearing. New one is about 3/8" from case. Adjuster had more than half adjustment remaining with old chain and guides are like new. Replaced chain and guides anyways.

Crank rotated counter clockwise like normal before I had the issue with the decompression pin falling out of the camshaft. Now it rotates clockwise with zero binding or noise, but will not go around counter clockwise like it should.

It has only been run on the stock chain and timing, not after I changed chain. There shouldn't be anything broken from me rotating by hand, I hope?

Oil was changed when I first noticed the issue and has less than 15 minutes of use, but it is over a year old and stinks like exhaust.

Thinking back, I recall the intake valves both lifting high. Does this mean I am way off with the timing and the piston is hitting the valves like Madkawi suggests?

So, could the broken decompression pin have been my problem since the beginning? Would it effect how the engine runs, if you can get it started? Sucks that a tiny little broken pin is costing me $80+ CAD...
So it sat for 6 months, then would barely run..
Now after sitting for another 6 month it seems to be locked up and the oil looks like shit..correct?

Just maybe moisture or water got into the cylinder and crankcase and has corroded the cylinder wall..or maybe its ice??
You could try dumping a cup or more of diesel fuel in to the cylinder leave it a few days. Just turn it by hand for now.
 

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Discussion Starter #19
So it sat for 6 months, then would barely run..
Now after sitting for another 6 month it seems to be locked up and the oil looks like shit..correct?

Just maybe moisture or water got into the cylinder and crankcase and has corroded the cylinder wall..or maybe its ice??
You could try dumping a cup or more of diesel fuel in to the cylinder leave it a few days. Just turn it by hand for now.
After sitting for the second 6 month period I could rotate the crank as usual and the engine is not seized. The problem I have run into now is apparently not having all of the gears timed properly after removing everything under the crank cover for inspection and to replace guides/chains. But, the engine is not seized as the crank rotates without noise/binding and the piston is moving smoothly (straw in spark plug hole).


I'm still not understanding why the oil turned like this with such little use on it. The machine has been in my shop since the oil was put in.


Parts should be in tomorrow.
 

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Can you post a picture of the oil?
 
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