2018 Polaris ... Have a peek see & Listen....

[takethebounce]

Nice breakdown. Just a couple of question the second version still had some issues life spans of 1300 k to 5000. I personally have only observed one go down with the lower k .though.

What is the longer break in period look like in respect to time and other variables to do it properly.

Cylinder skirt issues from 2011-2013 were a problem and lessened the reliability.

The break in period is controlled through the ecm on specific algorithms monitored by the computer but averages 150 miles.

There was an article I read not long ago from a Polaris engineer that even admitted they had "growing pains" as he called it with the Cleanfire but they were committed to its design and wanted to improve it.

All manufacturers have had their own growing pains. Doo didn't even try and give the SDI more than a few chances and went out and bought technology to adapt to the sledding world. Cat's long partnership with Suzuki and prior was anything but great although they got great mileage from the motors.

It's great to see the technology change. It only helps the consumer have a pull and go machine to ride and sometimes decent warranty.


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[Rhodesie]

Well just because you know everything already...

the CFI-4 in 2008-2010 port timing specs were the most radical of the three iterations, making around 154 HP with fuel leaned out with a DTR Power Commander map. But there was the inconsistent compression/combustion pressure control of the exhaust valves. Anytime one or more valves would be late opening during light acceleration, excessive airflow could occur and the air/fuel mixture could become leaner, creating possible detonation or lean surging and misfire.

The 2011 the CFI-2 version had much milder port timing, which created better part throttle compression pressure to open the exhaust valves promptly and more consistently. The milder port timing and revised valve timing made midrange airflow more consistent regardless if the exhaust valves were open or closed when commanded. So with the CFI-2 800, the dreaded midrange lean condition was eliminated, but unfortunately power was down roughly 8-10 HP from the CFI-4 800.

For 2015, the new 800 H.O, the exhaust valves are strictly controlled by an electronic stepper motor, and valving is expanded to cover not only the main exhaust port, but also the secondary ‘boost’ or ‘sub exhaust’ ports adjacent to the main exhaust port. The main exhaust port valve is a ‘double stack’ allowing the exhaust port height to be lower at low RPM, and at light throttle opening. At WOT (wide open throttle) the valves are fully closed from idle to 5200RPM, where they snap to ½ open. Then, at 7200 RPM they open fully resulting in smooth, torquey operation through the entire HP band.

Displacement stays the same at 795cc, but a new crankshaft is 2.5 pounds lighter, and a new piston/chrome ring package needs lots of break-in time to seal properly. Typical ‘moly’ rings seat well against nickasil bore quickly, but the chrome rings used in the 800 H.O. need time, load and extra oil to do the same.

So some could get porting and port timing mixed up easy enough. And saying the crank is the same design yet it's 2.5lbs lighter is pulling hairs.




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alot of good info here. good write up. i had a long chat with an engineer from the states last night and pretty much discussed all these very same topics.
what i was trying to say about the "base stock" of the engine is that the basic case design is the same, same volume, same oil entry into the bearings and rods, same crank design means its still a fuji
with the same length rod machined into a porkchop making it lighter. dementionally the same. the porting is the same and yes the "port timing" has been altered from the 4 to the 2 cfi to the ho.
what i am trying to get at is i personally would like to see them change the "platform" of this engine. it is small, light, and unreliable. is it a heat issue in the lower end? is it an oiling issue in the lower end?
there is a rumour floating around that they are working on a longer stroke. why not sacrifice a little bit of weight and add some coolant, make the bottom end of this engine a little larger(volume), and hopefully they do change the stroke also. i am sure there will be people say "i have 1500 miles on mine with no issues". well, your one person. there are still failures out there. its time for a complete revamp of this engine!

 

[kmcl]

Re: 2018 Polaris ... Have a peek see & Listen....

not a fan of traction or going up hills? what about deep snow?

I do just fine on a 15". Ever wonder why skidoos track and skid is so bendy?


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[cdnredneck_t3]

Re: 2018 Polaris ... Have a peek see & Listen....

What was the life expectancy of the 11-13 engines in trail sleds. I can't see those guys being very happy with 1500 miles. That could be 2 weekend's for some of those folks.

 

[takethebounce]

Re: 2018 Polaris ... Have a peek see & Listen....

What was the life expectancy of the 11-13 engines in trail sleds. I can't see those guys being very happy with 1500 miles. That could be 2 weekend's for some of those folks.

You hardly ever hear of the trail sleds having problems with any brand. Guys get 15,000km on etecs. Just isn't happening out here lol. The clean fire in the trail sleds doesn't seem to have been a big problem. Maybe not etec reliable but better than mountain use.


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[cdnredneck_t3]

Re: 2018 Polaris ... Have a peek see & Listen....

You hardly ever hear of the trail sleds having problems with any brand. Guys get 15,000km on etecs. Just isn't happening out here lol. The clean fire in the trail sleds doesn't seem to have been a big problem. Maybe not etec reliable but better than mountain use.


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My personal opinion on some of the skirt issues is guys running the pros too warm on the trails. Since a 2 stroke is pulling cold air into the crank case the bottom half of the engine and piston skirts will be fairly cool. So if guys think they can run them at 190 degrees like a 4 stroke all that is happening is your cylinder is warm and expanding and the piston is staying cool. Open up the Clarence combined with the skirts deforming and you just introduce quite a bit of slap going around bdc. Now you have piston and cylinder skirts becoming fatigued and breaking.

 

[takethebounce]

Re: 2018 Polaris ... Have a peek see & Listen....

My personal opinion on some of the skirt issues is guys running the pros too warm on the trails. Since a 2 stroke is pulling cold air into the crank case the bottom half of the engine and piston skirts will be fairly cool. So if guys think they can run them at 190 degrees like a 4 stroke all that is happening is your cylinder is warm and expanding and the piston is staying cool. Open up the Clarence combined with the skirts deforming and you just introduce quite a bit of slap going around bdc. Now you have piston and cylinder skirts becoming fatigued and breaking.

Yes heat is one of the primary reasons behind skirt collapse. The skirts on the early motors were thinner and did fail more. Going to a thicker skirt helped but as mentioned above the design of the block doesn't help with cooling.



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[Rhodesie]

Re: 2018 Polaris ... Have a peek see & Listen....

saw this earlier

2018 Polaris SKS 146, Looking good so far for the 2018 Polaris release on Monday.

 

[Rhodesie]

Re: 2018 Polaris ... Have a peek see & Listen....

more pics

 

[takethebounce]

Cut some weight out of the seat. I would expect a 399lb 155 Pro this year.


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[flying frenchman]

A few more .

 

[flying frenchman]

 

[adamg]

Re: 2018 Polaris ... Have a peek see & Listen....

If by good you mean "Bold New Graphics!" then yes, looking good.
A 146 SKS, a 20" utility sled, and a snowbike. Nothing for this guy.

 

[flying frenchman]

 

[Rhodesie]

Re: 2018 Polaris ... Have a peek see & Listen....

If by good you mean "Bold New Graphics!" then yes, looking good.
A 146 SKS, a 20" utility sled, and a snowbike. Nothing for this guy.

that was a copy/paste from another site. it kinda looks like that assault track of old on the 146.

 

[Rotax_Kid]

Re: 2018 Polaris ... Have a peek see & Listen....

saw this earlier

2018 Polaris SKS 146, Looking good so far for the 2018 Polaris release on Monday.

Pretty good spring offer if for a limited time you get rails, spindles, hoops, handlebars, windshields and panels. Makes sense why deals are better in fall.

Kidding aside nothing wrong with BNG. Usually the same models later in their production cycle are the best runners

 

[Jorgy]

Re: 2018 Polaris ... Have a peek see & Listen....

saw this earlier

2018 Polaris SKS 146, Looking good so far for the 2018 Polaris release on Monday.

This wont last long here lol. Looks like a 146" with a 2" track

 

[rmk600700]

Re: 2018 Polaris ... Have a peek see & Listen....

http://www.dootalk.com/forums/uploads/monthly_03_2017/post-115531-0-57887800-1488833953.jpg

 

[firstdoo]

Re: 2018 Polaris ... Have a peek see & Listen....

T-5 hours and 17 minutes

 

[Woodsie1984]

Re: 2018 Polaris ... Have a peek see & Listen....

http://www.dootalk.com/forums/uploads/monthly_03_2017/post-115531-0-57887800-1488833953.jpg

1200 xm turbo