Zr 500 melted cylinder ? - Snowmobile Forum: Your #1 Snowmobile Forum

04firecat700 · 01-02-2013, 08:40 PM

Friend of mine installed brand new engine 600 miles later mag side cylinder melted down? The piston by exhaust side is also like melted and burnt away ? He claim the 02 sensor our whatever it is fell out couple times would that cause melt down? We Checked for leak around intake boots didn't find any there

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smokingcrater · 01-02-2013, 09:04 PM

what year? as far as I know no ZR's have 02 sensors... They operate via open loop fueling only.

04firecat700 · 01-03-2013, 01:14 AM

Its a 02 zr 500 cross country

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**kccats** · 01-03-2013, 06:19 AM

That is a Pipe temp sensor! And most likely it is a crank seal!

04firecat700 · 01-03-2013, 06:38 AM

How big of a pain is that to change ?

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**RJ Gleason** · 01-03-2013, 07:35 AM

Requires a complete tear down and case must be split to change the seals.

04firecat700 · 01-03-2013, 10:43 AM

Is there any way to check it first ? I hope it ain't that... Only one winter of riding ok the engine

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**BC_Dan** · 01-03-2013, 10:52 AM

Is it an EFI or carbed?

**RJ Gleason** · 01-03-2013, 10:56 AM

If you have it assembled now, do the spray test.
Start it up and let it idle, spray starting fluid or carb cleaner around the intake flanges, the crank seals, and the cylinder bases.
It's harder to check the mag seal, but it can be done by removing the recoil or just spraying in through one of the holes in the housing.

04firecat700 · 01-03-2013, 11:03 AM

Its carbed right Now its sitting with the jugs off it

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**RJ Gleason** · 01-03-2013, 11:10 AM

The I'd replace the seals now, just for peace of mind.

93Wildcat700 · 01-03-2013, 05:43 PM

Its really not that hard FYI just need a decent flywheel puller aka (harmonic balance puller with grade 8 bolts)

Just take your time Get the bolt sequence for the case bolts and tighten them in the correct order and torque wrench everything. You could have that motor apart in a few hours tops.

Also you really need to figure out why that motor went down otherwise its going to happen again. why did it get a new motor the 1st time?

04firecat700 · 01-03-2013, 06:37 PM

I believe the power valve hit the pistons and i found why she blew the line from the oil pump to the bottom of engine came off we had new top end but it don't fit..online it sounds like the Cross country edition with power valves is a real pain... Even matters the color of sled

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04firecat700 · 01-03-2013, 06:39 PM

I don't even know if the engine is good oddly enough the thing ran descent before tear down..low compression on mag side was reason for tear down

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smokingcrater · 01-03-2013, 09:04 PM

Quote:

Originally Posted by 04firecat700

I believe the power valve hit the pistons and i found why she blew the line from the oil pump to the bottom of engine came off we had new top end but it don't fit..online it sounds like the Cross country edition with power valves is a real pain... Even matters the color of sled

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The valves don't hit the piston, it is physically impossible. They can come VERY close, but the dimensions prevent contact. What usually happens is that a worn ring or the piston skirt breaks, and the ring snaps out enough to catch the valve. Makes it look like the valve was the cause, but it was an innocent bystander.