Looks like as of 7/2/2008 the 850 has a different part number transmission assy. than the 550. Didn't see any parts changes though? Just the assy.
Also there are 2 different short blocks,no date or other explanation,just 2 listed with the same usage indicated. 1 is Nicasil(also called Nikasil,and other names)the other is iron lined....hmm
Kit, Short Block [EH0850LE011][Nicasil]
Kit, Short Block, Iron Lined [EH0850LE012]

I checked the numbers on mine and it is the Nicasil block.
If you remove the seat and look down at the motor the sticker will be on the back of the valve cover.
If you aren't familiar here is a couple of pages that talk about Nicasil..

http://en.wikipedia.org/wiki/Nikasil


http://www.poweredparaglidingo...aramotors/nicasil.htm


http://www.nicasil-zep.com/uk/niploy.html

 

Oddly enough the 800 short block is about $800 more than the 850! The blocks are about the same price. The iron bore I haven't found,looks like it maybe a new addition? The listing list all included parts for the 800 but not for the 850,but it shows the same parts in the picture...block,head,valve covers ect(most of us mech call this a long block really)

 

So what's your take on these changes HIGHOCTANE?

Just supplier changes, or something more to it?

 

I bet the iron cylinder is military spec... The military probably buys alot of Polaris ATV's and can spec their own motors.

 

Not sure really. I'd be intrested to know if there are actually iron bore motors out there. Alot of possibilities exist. Nicasil doesn't like high sulfur fuel,some countries have higher sulfur content fuel....would Polaris go to the trouble of building iron lined blocks for those countries and Nicasil for everywhere else?
Are they using iron blocks,or is that listing just an option to do so should the Nicasil blocks become short supply?
I could theorize all day...
Hard to say without more info...
Iron lined is cheaper...
I'm not sure really.

 

<div class="FTQUOTE"><begin quote>Originally posted by: HIGHOCTANE

I'm not sure really.</end quote></div>

Something tells me you will be... soon. LOL

 

<div class="FTQUOTE"><begin quote>Originally posted by: looking

I bet the iron cylinder is military spec... The military probably buys alot of Polaris ATV's and can spec their own motors.</end quote></div>


I thought of that,but the Govt models aren't included in the parts listing I'm looking at....

 

<div class="FTQUOTE"><begin quote>Originally posted by: HIGHOCTANE

Looks like as of 7/2/2008 the 850 has a different part number transmission assy. than the 550. Didn't see any parts changes though? Just the assy.

Also there are 2 different short blocks,no date or other explanation,just 2 listed with the same usage indicated. 1 is Nicasil(also called Nikasil,and other names)the other is iron lined....hmm

Kit, Short Block [EH0850LE011][Nicasil]

Kit, Short Block, Iron Lined [EH0850LE012]



I checked the numbers on mine and it is the Nicasil block.

If you remove the seat and look down at the motor the sticker will be on the back of the valve cover.

If you aren't familiar here is a couple of pages that talk about Nicasil..



<a target=_blank class=ftalternatingbarlinklarge href="http://en.wikipedia.org/wiki/Nikasil
">http://en.wikipedia.org/wiki/Nikasil
</a>


<a target=_blank class=ftalternatingbarlinklarge href="http://www.poweredparaglidingontario.com/paramotors/nicasil.htm
">http://www.poweredparaglidingo...ors/nicasil.htm
</a>


http://www.nicasil-zep.com/uk/niploy.html</end quote></div>

[img]i/expressions/face-icon-small-happy.gif[/img] just my 2 cents worth,I've seen some horrible seizures on our KTM dirt bikes that are nikasil and 95 percent of the time we just lightly hone out to break the glaze and throw in a new piston!! We have a lot of cross country and enduro riders that are pretty tough on their machines,and they would be going through a lot of resleeving if not for nikasil! Usually the only time we send em out for recoating is after about 3 years HARD racing! Also to compensate for a little wear,slightly larger pistons are available( group 1 is stock,group2 and group 3 oversize slightly) If Polaris's coatings are as tough as KTM, No worries on my end! Good luck

 

Sounds like a good, tough block. Should make HIGHOCTANE feel better. LOL

 

Nikasil lined cylinders are very wear resistant, unless a ring breaks and scars the cylinder. Also it helps with heat dissipation and eliminates the dissimilar metal problems.

Porsche, BMW and several others have used this technology for years.