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Discussion Starter #1
I tore my top end down today and found out that I have allot of moly missing off of my rings also.

I'm taking the pistons and rings to Novi on Sat and asking the Doo rep what they are going to do about it. You will know if I had made it to the Doo booth or not if there is a set of pistons hanging out of someones rear-end.
 

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Took my machine apart to install some welded pistons( dual ring Weisco's) and found some wear on my rings as well. It only has about 900kms on those rings and I use Amsoil injection oil and FAITHFULLY warm the unit up so I was surprised.
 

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Could someone post some pictures of what their rings look like with the missing (or partially missing) moly coating? I pulled the RAVE valves on my 01 800 (updated pistons) and it is hard to tell if the moly coating is missing. I didn't feel like tearing it down quite yet. Either it is all there or it is all gone!

Thanks!

:(
 

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Checked the rings on Ladyk's 02mxz800 gade when i took the Ypipe off and they look fine the pistons have no visible scuffing also This is after 5000 kliks of me driving with amsoil
 

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Is this happening on the exhaust side? If it is could it be from ring flex?
 

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I had a peek at mine as well and they look good.Comp is at 148,149.Apparently you will not see a lose in compression if the ring is just flaking.
 

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would like to see a pic of these flaking rings, checked mine out, looked ok 1500 miles using bombi regular injection oil. im happy about that 2nd year engine warranty...we will have to wait and see what skidoo is going to do....
 

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Discussion Starter #10
I have seen a couple of sets of rings that were allot worse than mine, and had the moly gone on the intake siade, and missing some near the ring locating pin.

My comp was great before I took it apart, 153 PTO/ 150 MAG

Looking at mine, the moly was worn thru, not flaking. There are many out there that are. I know of one guy who has under 300 miles on a 2002 MXZX800, an his are the worst I have seen.

Also, my recall pistons had shrunk. The skirts are no longer tapered, and the piston in strait from the pin down, leaving me with .011" of clearance (.0055 a side).
 

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Hi 800 men!


when i check my mach-Z ring at 20,000 milles they were in pretty good shape,the 3 pistons also!!
Sorry the Z is dying!!!

Z36Qc ;)
 

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The last time i see this problem on moly coating was on my blizzard 9500 and on my 583 engine.Personnally i think it's a bad batch of Rotax ring.Because after changing mine on my 583 engine (top ring) thet nerver failed and i check my engine each year and i change my snow at 13000 milles!
I would try a new batch of ring like 2003 production to resolve this issue,let your engine to heat for 5 to 10 minutes before going snowmobile and used good injection oil,it could be an oil issue also.Put 6 to 8 ml of oil in fuel tank for each littre of premiun fuel!! After 35 years on snow,its would i try!!

Good luck! Bye Z36qc
 

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I know this can't be great, but help me understand the issue.
With the moly flaking/wearing off and the compression
unaffected, what is the detriment? Is it friction?
 

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Discussion Starter #14
Mine have yet to get bad, I cought them right as they started to go, thus the high compression. I know of one friend who had 50% of the moly gone off of his, and his started to loose comp. in one cylinder.

Mine was at the point of just having a problem.

I have posted pics in another thread in the Doo forum for you to see.
 
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Are these rings flaking on 01's and 02's? I have an 02 with 1300 miles and this topic is scarin' the crap out of me. I run nothing but amsoil. I put new reeds on this year and when I had them off I checked the intake side and I saw no problems. I also checked what I could when I had the raves off. Again, all looked good. I am checking compression tonight. If this is a ski-doo problem, I wish they would just address it. If my motor pops this season from this and I'm stuck 100 miles from my hotel.......man this @hit is getting me hot!
 

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The hot spot is usually in the area between the main and boost exhaust ports. With the lean condition in the mid range and fat jetting on top, it shows up at different times, depending how you ride. The 'tub' style head in these motors resists detonation so instead of smearing or holing the piston the rings see too much heat and come un-glued. Put a 'hemi' head on it and your smear before you loose a ring. Lost two rings in my 700 improver on the dyno. Way to lean on the jetting. The thing would not sieze with C-12 and synthetic Klotz, so the rings let go instead. How many 'old' 670 motors had flaking rings?
 

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Those that have flacking could you post what oil you are using, I am interested in seeing the flacking and what oil is being used, I have used Amsoil 2000 for two years now at 800 miles, I checked the valves, very little carbon, first tank of oil was ski-doo oil. The carbon was easy to wipe of, it wasnt the common carbon you have to scrap of with a blade.
 

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Discussion Starter #18
I know three guys with prob.

1 is a 2002 using Regular Doo oil. Flaked rings 2000 miles

Next is using Doo Synthetic, 2002, with less than 600 miles (and has the worse ring flaking)

And mine, 2001 (Recalled pistons) with Klotz oil. I had 1100 miles on it, and my rings were just starting to show problems.


From what I have been told, is that the ring is too thick and holds too mush heat rather than transferring it to the piston. The rings get hot, and start to not seal. Thus really hurting top end. The coating comes off the rings due to the extreme temps of the ring.

personally, I am switching to an aftermarket pistons. I am done with elko, and just about done with the series 3. If this does not turn out good, I will be switching my name to 800SKS
 

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I have a 2002 800 with no flaking at all. I changed the head when it was brand new to the Cudney setup, and I have been running the Blue Marble oil the complete time. I also have an EGT gauge and found out about the midrange lean spot the 1st time I rode it. I installed a .010 washer under the needles and then ordered the 942 needles from Ski-Doo. No more lean spot and I get bewteen 10 - 13mpg depending on the amount of wot's on the big lakes.

It runs great!!!!

800x2002
 
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