850 Engine thread (840cc)
- Thread starter mountainhorse
- Start date
Bore and stroke seem pretty good. Larger clutch taper and crank should add to reliability.
173hp? That would be a huge jump and I doubt it. 160? Maybe. 175 with mods? Sure.
Time will tell. Nice to see someone else going beyond 800ccs without making ridiculous bore/stroke decisions.
173hp? That would be a huge jump and I doubt it. 160? Maybe. 175 with mods? Sure.
Time will tell. Nice to see someone else going beyond 800ccs without making ridiculous bore/stroke decisions.
R
crappy!
Bummer, hopefully MAPE has stepped up their game in terms of quality.
After looking over this engine quite carefullym it is impressive to see the advancements in technology,. They have brought the 900 CFI of old a LONG way in 13 years. The advancement in cooling system technology found on this engine is quite possibly one of the coolest portions of the engine design. The fuel pressure/temp sensor is going to be vital in protecting the engine from its biggest enemy (its owner). That sensor is probably the most overlooked bit of tech on the whole package, can you imagine how many PRO engines this would have saved from plugged/restricted fuel filters? I would also speculate that Polaris will be able to add an alcohol sensor to it and the days of switching between fuel types will be gone.
Polaris + new motor=
I really hope this motor is better than the other ones they've built this century. Nothing like selling your sled with less than 2k on it because you have zero faith in the engine.
I really hope this motor is better than the other ones they've built this century. Nothing like selling your sled with less than 2k on it because you have zero faith in the engine.
G
I agree!
I don't understand why Doo and Polaris think a single ring piston is a good idea (the Doo 850 is also single ring for some reason).
Single ring pistons are fine on a 125 dirt bike that gets rebuilt often and you are trying to get the max power you can.
IMO, it makes no sense on the large bore of two cylinder snowmobile that is not getting rebuilt often and the power difference would be minimal.
Maybe they know something.
I don’t assume they would change from dual ring to single without some purpose?
A large ring with longer piston will rock less (piston and ring) and maybe that’s the idea?
I saw a note about a redesign of the exhaust port, perhaps the large single ring spans the gap better without snagging?
S
100 yrs skidoo used single rings.LOL.nothing wrong with that.
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Not only is the new TPS "no adjustment needed"...
It looks like it is not adjustable physically.... probably a new sub-routine on digital wrench if it is needed.
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It looks like it is not adjustable physically.... probably a new sub-routine on digital wrench if it is needed.
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This is probably ALSO another one of the little details but possibly one of the msot key upgrades. The amount of variation in performance based on faulty or semi function TPS sensors. INSANE.
Polaris motors are not even at fault half the time. Its the systems and components attached to it (fuel filters, cooling system, electrical etc) that lead to the demise of the motor. Better controls mean better performance and more longevity.
Polaris motors are not even at fault half the time. Its the systems and components attached to it (fuel filters, cooling system, electrical etc) that lead to the demise of the motor. Better controls mean better performance and more longevity.
R
wonder if it would be beneficial in having the injectors tipped up as to discharge more towards the top of the boost port instead of injecting in to a brick wall. maybe its an atomization thing.
Its an atomization thing.
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G
Lol
I suppose they have been blowing up about that long as well
Seriously though, didn't the REV 800s have single rings and lots of issues? Didn't the 800 Dragon's have single ring pistons?
These are some of the worst 2 stroke engines reliability wise from the last 15 years and had single rings.
current doo's 850 also use one ring
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