It's a sad day of my own...

maxitout77 · Nov 1, 2012

2011 Pro 800. 1600 miles. No engine mods whatsoever, bone stock. Never overheated. Polaris VES Gold since day one. 3 turns out on the screw since 900 miles. Needless to say I'm really disapointed. WTF.

This is the "good" side:

Bad side:

Now this gauge is usually within 5psi.

Let the teardown begin...

PaulAnd · Nov 1, 2012

The Bright side is... it's time to make it more awesome!! IMO Send the cylinders out to get checked for cracks so no worries after refresh

knifedge · Nov 1, 2012

--crank bearings and pistons

Powerage · Nov 1, 2012

These engines are only 110-120 psi on a good day. Just so you know. Those readings don't look that bad.

skibreeze · Nov 1, 2012

Where's the 30 psi difference?

Rick! · Nov 1, 2012

maxitout77 said:
2011 Pro 800. 1600 miles. No engine mods whatsoever, bone stock. Never overheated. Polaris VES Gold since day one. 3 turns out on the screw since 900 miles. Needless to say I'm really disapointed. WTF.

This is the "good" side:

Bad side:

Now this gauge is usually within 5psi, but not off by 30psi+.

Let the teardown begin...

What are the issues with how it runs? What RPM did it pull b4 it got warm last spring?
Gone through the clutches lately?
What was the compression at 0 miles? 900 miles?
What altitude are you doing the compression test?
Did you pull the exhaust manifold off and look at the pistons?
Borescope it?
Compression test is only one checkbox for assessing engine health, there are a few others.

http://www.snowestonline.com/forum/showthread.php?t=317784&highlight=leakdown

beamslayer · Nov 1, 2012

Hows your warranty, if you do not have one it is worth a piece of mind to tear it down and check the rings for flaking and take a peek at the cylinders . Also you could try another compression tester . While you are in their measure your pistons and if they are collapsed start looking at different kits.
Sorry but it is the new polaris tune up.

dexter · Nov 1, 2012

those readings look pretty close no 30 lb diffrence there maybe 6 or 7 lbs. how many miles you got?

maxitout77 · Nov 1, 2012

30lbs was a typo, didn't mean that.

readings were taken cold, did each cyclinder 3x to get best result. These are the highest numbers I got.
No warrenty. 1500 feet alt. never did a comp before on this sled. Ran perfectly fine.

Beamslayer: After seeing your thread, I am most definitely tearing it down for inspection (hence my title

)

Sorry guys, im used to Doo motors that pull 140-150 psi. Why so low on these?

beamslayer · Nov 1, 2012

I hope you are one of the lucky ones and only need pistons. Than comes the hard choice who's kit do you yous .
If funds were not a issue I would be talking to Carls or Power Addiction and going for a 900 or 910 .

maxitout77 · Nov 1, 2012

Top end is torn down, not too bad a task. I am lucky in the the cylinders look great and no signs of damage or cracks at all. I checked and cleaned numerous times.

A closer look at the piston DOES show exactly what caused Beamslayers issue. The bottom of the piston skirts show wear (both sides). This is the only part of the piston that looks "clean". IE its rocking/rubbing and keeping the metal looking fresh. I do realize some piston wash will happen (as this is the intake side), but there is actual noticeable wear into the piston itself beyond it being clean

I also just got off the phone with Kelsey from RKTek and will be ordering his direct replacements. He confirmed that the piston wear I'm seeing coincides with the "sloppy" piston design and potential failures. We both have no doubt that if untreated, it would lead to cylinder/piston failure (over time).

beamslayer · Nov 1, 2012

Glad to hear about the cylinders how do your rings look ?

PaulAnd · Nov 1, 2012

Not doing Kelsey's head?

snowmobiler · Nov 1, 2012

the 1 ring must be toast.?

skibreeze · Nov 1, 2012

snowmobiler said:
the 1 ring must be toast.?

If you would read as much as you type, you would know that they have 2 rings.

flying frenchman · Nov 1, 2012

Yes. Excellent question, why so low of comp from the factory. Are those motors like that so they will last.

AKSNOWRIDER · Nov 1, 2012

measure the bore top, middle, and bottom, not uncommon for them to be tapered ..most likely it will need renic'd...fully explore all options on replacement "kits"...from what I can see....looks pretty good really...these motors with a stock cylinder must have enough clearence or they will scuff pistons on longer pulls...keep that in mind.............

AKSNOWRIDER · Nov 1, 2012

flying frenchman said:
Yes. Excellent question, why so low of comp from the factory. Are those motors like that so they will last.

what a cranking compression test shows isnt always a true indicator of a motor..so many things affect compression...agressive port timing is number 1 with showing low compression on a crank test, as will looser bore clearences among other things..doesnt mean the motor is broke or wrong..

flying frenchman · Nov 1, 2012

Wouldn't the motor be alot snappier with more comp.

AKSNOWRIDER · Nov 1, 2012

depends..what it shows for compression at cranking speed may not be close to what it really is at running rpm..its similar to running a car motor with a really big camshaft(high lift real big duration) it knocks your cranking compression numbers down but running compression is where it should be(I used to run a pro mod style big block chevy nitrous motor..with a static compression of 15.5 to 1 it only showed 155 pds on a cranking compression check..yet put out well over 950 hp motor only on the dyno...low cranking compression was due to the huge lift(.865) and extremely long duration(well over 320* at .050)...cranking compression is really only a guage of piston/ring/cylinder condition when monitored from new thru its life cycle...

It's a sad day of my own...

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