06 summit 800/159 engine trouble, SQUEAK!!

[readyandwilling]

On my weekend ride my 06 800 started to bog a bit about 10 km's from the truck, a quick feathering of the throttle seemed to clear it up and the RPM's came back but only for a moment. It then started to bog down again and throttle feathering had no effect. I stopped and the sled died right out. I tried to re-start with the e-start and it turned over very slowly but did not start so I tried to pull start it and she was tight, I could not even pull it over. Pulled the belt off towed it out and headed home.
Once at home I pulled the plugs to see if she was lean, PTO side looked good if anything a little fat. MAG side was very white looking. I did a compression test PTO side 140+, MAG side 0. She has to come apart.
I started tearing into it to see what I could find. When I got to the power valves the PTO side came out real easy, (a little dirty, needs cleaning but nothing bad). The MAG side was very sticking coming out and had to wiggle and tug to get it out, it is completely covered in gummy oil.
I am now trying to mess with the Y-pipe bolts (PITA) to continue the tear down but in the meantime wondered if anyone had any ideas as to, why the MAG side would all of a sudden be lean and the PTO side is not. Once I get the head off I am sure I will get a better idea as to what is going on but am looking for some input, feedback and ideas on what happened so that when I get it back together I can prevent it from happening again right away.

 

[readyandwilling]

Pictures

Igot the head off and this is what I found but I still don't know why. It looks like I will need a new jug as well as piston and rings.
Input??

 

[readyandwilling]

Another picture.

 

[sledsrock]

Check your reed boot(s) for tears/delam..........

 

[readyandwilling]

I will have a look at it when I pull the jug off.

 

[Tackbtch]

My 06 did the same. Turned out to be the crank seal on the mag side...sucks...Dino

 

[readyandwilling]

Looks like a major failure!!

I am no sled mechanic so I am looking to the forum for some input. Anthing you guys could help with would be great.
I have the engine torn down and the jug off off the MAG side attached is a picture of the piston and the RAVE valve from that side.
The rave valve is covered in very gummy oil almost feels like dried pancake syrup when you touch it. Don't what it is or why it is so gummy.
The cylinder wall is damaged quite bad and the small exhaust ports are cracked through to the main port.
I have checked the carb boot (looks good), checked the reed bellows (looks good), checked the RAVE bellows (looks good).
Why was that side so lean and why did the skirt fail? The piston ring appears to be stuck againt the piston right where the damage is, don't know if that helps but I thought it can't hurt to give to much info.
I dont want to get it all put back together only to see that same thing happen again.
Any insight that you can provide would be very helpful as I am really just faking my way through the repair trying to tell myself I know enough to get it done.

 

[mxracer328]

looks like it is detonating due to the white specals on top of the piston. also when was the last time you cleaned your carbs out, having a clogged pilot jet will cause it to lean out (speaking from experience). hope you get it figured out man.

 

[readyandwilling]

Can the clogged jet in the carb cause the skirt to give out?
I spoke to a local guy and he is telling me that he thinks the crank bearing is gone on the MAG side and that is why the skirt failed.
I am leaning more toward some other reason for the failure maybe it is wishful thinking. I will check the jets and update the post.
Thanks!!

 

[readyandwilling]

Could it lean that side out if the RAVE valve was either stuck open or closed because of what ever the sticky residue is?

 

[mxracer328]

i dont believe so, rave valve works on posotive pressure fro the engine, for it to lean out it would need to suck air. mine are sticky too, good idea to clean them every few rides. crank bearing seal may be another possibility. my opinion, compare the price of rebuilding that motor and dropping in a crate (wheres theres warranty) then ou can always fix your motor and sell as a whole, and it you wold work out to near the same price.

 

[readyandwilling]

Update

Well, I think I found out the "why" I was looking for. Thanks to your input. I found that the jet in the bottom of the carb was almost completely plugged. I blew through it backwards and the opening is now at least twice as big.

 

[mxracer328]

thats your main jet, and if that is clogged that bad i would highly suggest cleaning all your jets

 

[readyandwilling]

I did clean the other main jet but it seemed fine. How do I get at the pilot jets to clean them out?
Am I going to need to have the dealer reset the the TPS when I put it all back together?

 

[mxracer328]

pilot jets, im not to sure, i was hoping you could tell me because i have to do it tonight or tomorrow. but they arent super complicated, ive had my dirt bike one apart lots, just take your time and remember where chit goes. have you changed the piston in there yet?

 

[readyandwilling]

No have not changed it yet. I debated between changing only the damaged one because the compression on the PTO side was over 140 but because I am going with an aftermarket piston I was concerned about throwing things out of balance so I ordered two pistons and a new cylinder.

 

[Danzick]

yea good choice. id never mess with that kinda stuff. buy stuff in pairs! haha and it pry wouldnt hurt to hone out the other cylinder a little while you were at it. unless its in like perfect shape. just a thought!

 

[readyandwilling]

Yeah thats what I thought as well thats why I ordered two.

I did have a B..CH of a time getting the wrist pin out of the dead piston. I wound up having to heat the piston with a heat gun, support it with my hands while holding a rag so as not to burn my hands. Then tap it out with a deep socket on an extention and a rubber mallet. I got it out and was still able to recover all of the 28 loose rollers.

I am still looking for some input on restting the TPS sensor after I get it all put back together. Will I need to reset it and if so, how