THOUGHTS... FACTORY 4 STROKE IN AN AXYS CHASSIS??

Motorbreath_ · Jan 6, 2016

I might get flamed.. but a factory built 4 stroke axys would rule the 4 stroke world. Not saying abandon ship on the 2 stroke. But offer a 140-150 hp 4 stroke as well.. and watch the Yamaha and Arctic cat guys flock in.. wouldnt be long before ski- doo followed along. That is unless they are already working on one.

Moderator Note:
I copied this here for better discussion from another thread... great topic!
MB, your original post is still intact in the 2017 thread.

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Uncle Bob · Jan 7, 2016

Motorbreath_ said:
I might get flamed.. but a factory built 4 stroke axys would rule the 4 stroke world. Not saying abandon ship on the 2 stroke. But offer a 140-150 hp 4 stroke as well.. and watch the Yamaha and Arctic cat guys flock in.. wouldnt be long before ski- doo followed along. That is unless they are already working on one.

Not trying to flame you at all but consider this coming from a guy who just came from a proclimb to an axys, the single biggest advantage i think the axys has over the cat is the chassis is built to only accept 2 stroke and not the bigger and bulky four stroke. i respect your love of the motors though

RMK-King · Jan 7, 2016

Apex engine in a Pro.
http://www.snowest.com/forum/showthread.php?t=406735

mountainhorse · Jan 7, 2016

The AXYS and ProRide are nimble because of the low amount of gyroscopic effects and low weight of the compact power plant....

If a four stroke were to be successful in this thing... it would have to have an evolution in compact power... much like the trasnformation of a 4-S dirt bike.

A 2 cylinder 800 -1000cc lightweight twiN, boosted, power-plant, IMO, would be the only way to have an effective 4S Mountain sled in this kind of chassis.

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icr · Jan 7, 2016

the majority of people who won't buy Polaris say it's because of engine longevity, poor power, or both.

Many who buy Polaris sleds add turbos at $4k+ on top of a 12-13k sled.

If Polaris released a factory turbo four stroke with 160-180hp under 500lbs, they would convert a lot of riders.

MH, you never mention gyroscopic effect when promoting the heavier chain drives, it's interesting you bring it up here. Ive ridden a lot of four strokes and the weight was noticeable as well as suspension set up, but if weights were equal I would take an apex over an xm every day for any type of riding.

mountainhorse · Jan 7, 2016

icr... good question... IMO... the gyro effect of the chain-drive equates to the difference in weight of the chain and top sprocket... as the lower is part of the track rotating assembly. (track/drivers/driveshaft/lower sprocket/rear-idlers)

But hey... people who are a lot better riders than me... with more seat time (I'm envious of that part).... like them and swear by them. Nice we have a choice in this now, don't ya think!

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die hard poo · Jan 7, 2016

After riding the new viper with a 270hp turbo kit it really turned me off on the whole 4 stroke deal. I was really hoping on a decent chassis the weight wouldn't be so apparent. But it is. No matter how much power (which this sled has A LOT), it never felt light. I tried to ride it how I do my 2 stroke, but it always felt like it had a 100lbs extra on the skis.

Plus now the AXYS makes decent power, it feels the gap for me. Also it seems the AXYS motor is responding very well to boost after watching some of these vids of the BD side kick turbo kit.

Northern18 · Jan 8, 2016

Forget putting a 4stroke .... just offer a turbo'd 2stroke and watch the profits grow!!

M8onEdge · Jan 8, 2016

Rear end of the Polaris skid is relatively light....like one hand light. If you look at pics of the sleds being weighed the doo hangs the rear end on the floor, cat is about mid way to the floor and the poo is pretty balanced. Drop a four stroke in the front and it's going to be a lot of weight in the front end. Maybe it's something they can work out but the overall balance on the sled is what makes it work. It would be nice to have an engine that would run more than 1500 miles with some confidence though.

NytroNorm · Jan 8, 2016

I like your idea but I don't think the technology or the market is there. At leas not in the mountain segment.

If you want to talk trail segment, then Polaris has to build a 4S as reliable as Yamaha and I don't see that **** happening any time soon.

The amount of guys wanting to buy an overweight mountain 4S is nill. If Polaris is going to go after a different market, it certainly wont be Yamaha's. Just have a look at the viewing numbers here on snowest, Polaris has almost 7 times the viewers, currently and on a regular basis.

Jaynelson · Jan 8, 2016

4 stroke sleds are pretty much sales proof here....turbo, no turbo, etc. If they do ever go down that road, it needs to be something revolutionary ala the dirtbike world where you don't have to give up so much performance and feel.

RMK935VA · Jan 8, 2016

Jaynelson said:
4 stroke sleds are pretty much sales proof here....turbo, no turbo, etc. If they do ever go down that road, it needs to be something revolutionary ala the dirtbike world where you don't have to give up so much performance and feel.

I don't think that you could get the Polaris twin in the Axys chassis.

jskattum606 · Jan 8, 2016

I built the ProPex that sledmax posted a while ago. I think making a 4 stroke feel a lot like a 2 stroke, At least as close as the dirt bike world is very doable.
The Propex felt so much like the pro that i was very happy with it. The front just felt a little heavier. It was close enough that i think with a great 4 stroke engine design it can be done.

But as happy as i am with it...... a builders got to build:face-icon-small-hap

yamahajohnson220 · Jan 8, 2016

I am very surprised this topic has been so civil without childish bashing. All posts have been on topic and prove great points good or bad. I am a believer in future 4s technology only because of my past Mx days and have ridden/owned 2s & 4s, boosted and n/a of all kinds of powersports. I'm not all saying we should get rid of 2s but I think it would be great if all the sled mfg's made both engines in a great chassis like the Polaris Axys. I think it's do able from the Polaris camp. They obviously have the money and design resources to put a plan in action. As of now I can only dream of having my turbo viper engine in the superior handling Axys chassis without no ill effect's of weight.

Dam Dave · Jan 9, 2016

Someday one of the manufactures will build a lightweight high performance 4 stroke like the motocross world has, then you need to build a chassis just for that engine, not adapt something generic, in the motorcycle world each chassis is built around a specific engine, until the snowmobile manufactures do that a 4 stroke will always be a compromise and a failure

89sandman · Jan 9, 2016

I think Yami was heading the right direction with the phazer motor. Instead of basing it off the 250f motor use the 450f, add boost, and wham you've got a quick revving motor that would be able to compete with a current stock 800cc. A twin with boost is the only hope a 4 stroker has to compete in the mountain market. The downfall will be by the time they lighten it up enough to be close in weight it won't last or be anymore dependable than the 2 stroke.

Jaynelson · Jan 9, 2016

Also remember that with the 4s mx service intervals that would come with such a motor...you would be changing oil every 2 good rides. Sled rides are typically longer and more throttle and load than moto

TimG · Jan 9, 2016

The main reason that 4 stroke MX bikes have taken over is that there are rules in the AMA pro classes that give an enormous displacement advantage to 4 strokes (450F to 250T, 250F to 125T). If they were forced to race cc for cc, however, four strokes would be at a tremendous disadvantage because of the superior power per cc of two strokes. Mountain sledding isn't based on racing class rules- no one cares about that stuff here. Power to weight rules in mountain sleds. Therefore, I can't ever see four strokes taking over in the mountains. The only way would be if a manufacturer poured money into a design to make the four stroke engine and sled really light. Possible but unlikely. And it would probably cost 30g.

I think Yamaha thought that they'd come along and revolutionize snowmobiling by introducing the 4 stroke the way they did in the MX world, but it hasn't really worked for them in the mountains. Weight just matters too much.

On the other side of the coin, there are some advantages of a 4 stroke that are pretty significant. The power spread is huge, and overrev is awesome. Tractability is great too, with the engine firing on every 4th stroke instead of every 2nd. I have a 450 and love it. Sled is a different ball game, though.

Motorbreath_ · Jan 9, 2016

No one claimed the fourstroke Axys would take over the 2 stroke world.. but it would take over the 4 stroke mountain segment, that does exist.. may be small, but it does exist. I believe with a superior product to the Viper and M9000.. which are both fairly capable sleds in there own.. I think some 2 stroke guys will convert. The 16 Viper is a very easy to handle sled. Im a small guy and I have no problem throwing it around. I can only imagine a 4 stroke Axys with a 36 inch ski stance. A guy can dream I guess.

Wyopowder · Jan 10, 2016

A high performance four stroke may be less weight penalty than is currently being used by cat n yami. Take ktm xc 300 two stroke@51 hp total bike weight 100.7 kg then take 350 xcf four stroke @ 58 hp 105.7 kg (numbers from website) same chassis same bike between two motors. That's not that much difference in motor weight and the 4 stroke has more hp for only 50 more CC's. Ok take the four stroke engine double it that's a 10 kg weight penalty and possibly a 120hp motor result add another 8 kg for turbo/supercharger. About 40 lbs total additional and decent hp. That might work. If there is a will there would be a way but marketing geeks say not enough units to sell and accounting says it will cost too much. I would look very hard at a Polaris 4 stroke boosted 160 hp @ 450 lbs hmmm

THOUGHTS... FACTORY 4 STROKE IN AN AXYS CHASSIS??

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