I just don't know about these heavy 4-stroke engines. Yeah I know, old topic. But no matter what, these engines are going to be a lot heavier than 2 strokes, and so far the peak horsepower isn't any better either. The worst thing about snowmobiling is the weight as far as I'm concerned. Even the lightest modern sleds could stand to be a lot lighter. I ride these 10+ year old rigs, and really the only thing that makes them obsolete (performance-wise) is their weight. People talk about suspension/ride improvements over the years, and that may be true but for my application (mountain) I can't tell any difference in ride quality between my 99 RMK and an 06 Summit (on or off trail) except the Summit is lighter and therefore easier to maneuver. Yeah my rigs have a few aftermarket upgrades but the total cost is still 1/4th to 1/10th the cost of a new sled. Those savings buy a lot of gas.
So...why do people want to downgrade performance and upgrade riding effort? A brand-new 4-stroke sled with a modern chassis (especially a Yamaha) would still be heavier or just as heavy as my old obsolete 2-stroke sleds, and with equal or lower peak horsepower from the 4 stroke. A newer 2-stroke from any of the brands is the only real upgrade, at least on paper, that I can see. I know the 4s have unmatched low-end but frankly good clutching is all you need to make a narrow power band engine (like my piped 700 RMK) put out crazy power at all throttle positions. That's really the point of the CVT isn't it? I have found this to be true on every sled I've tuned, which is all of them, single or twin exhaust and always piston ported engines. Just get the engine to its powerband and make sure it shifts at the true peak and you are golden. If anything, I think this 4-stroke trend is a backlash for the brands putting out sorry stock clutching setups and thus making people think the 2-stroke limitations can't be overcome. It's a shame really. More torque means easier clutching, and so that historical tuning laziness is now coming back to bite the 2-stroke brands.
This is not dirtbike racing where you have to shift through regular gears and you must have some low end power. No, good smart CVT clutching can just eliminate the weak part of the power band and you are shifting at your peak the entire time. So I don't buy the low-end torque arguement, but I think too many people have ridden on stright helixes and such (old-fashioned stock clutching) and don't realize how much improvement there is in newer sled clutching or aftermarket upgrades for older sleds. Just one simple change of putting a 38/34 progressive helix and matching spring in my Indy 500 EFI (no other upgrades) transformed the performance from "dog-like" to "very snappy and fun" instantly. I'll race it against a stock 07 phazer mountain light any day, and I have no doubt the Indy will blow away the phazer given the same track. Just look at the peak power and the weight of both and it's obvious. The Indy jumps right to 8000 RPM and stays there, so don't tell me about low-end torque...what low end? How would more low-end help when you never use it? The Indy is lighter and at least equally powerful. Oh yeah, and it's also 15 years older and I paid $750 for it. That's why I'm having trouble seeing the 4-stroke appeal. The Indy EFI also gets incredible mileage, never used more than half a tank in a day, usually it's more like 1/4 tank. I can't believe a comparably-powerful 4-stroke would do any better.
And I'm sorry but if Jim from SLP can figure out which helix to slap in an old Indy to make it scream, these OEMs should be able to do even better. Maybe today they can, but in the past they sucked (or didn't try) and that's what most people remember about their old 2-stroke sleds. Good clutching gives you all the pull in the world, you don't need a heavier engine for that.
So is it really just the smell? Really? Or do people want their sleds to behave more like cars? Well at any rate I've never ridden one so maybe that will be the difference, I need to try one in person. I like the idea of increased fuel economy, my piped RMK absoultely sucks it down, and I want sleds to be cleaner in general. But personally I like the E-tec direction rather than the 4-stroke. Is all that extra weight and complexity really a good trade for extra low-end grunt but no extra peak horsepower? I don't see it.
Anyway this isn't a flame but an honest question/discussion topic. Why are people honestly buying the 4-strokes? I just can't believe it's the performance. Sure you can turbo it, and then there goes your wide power band and fuel economy right out the window! I don't get it. I guess if you are never going to jump it or go off trail at all and the trails are always groomed then maybe the weight doesn't matter? And yeah, if you are riding an old broken-down clunker then of course any new sled is going to seem like the best thing ever...well maybe, I sure couldn't wait to get off the REV and back on my RMK because of the knee pain even though the rev is a better ride... and I think it's no coincidence that you can't go out for test drives on these things unless you catch a special event. Ignorance is bliss, right? But hey I'm just looking at the specs, maybe there really is something to this. I'd like to know.
Edit: 570 pounds for a short track performance sled? The ski doo at 540 pounds looks like a dog, the Yamaha at 570 looks unbearable. We are talking about an extra 100 pounds here in some cases compared to 2 strokes. Or put another way, the four stroke sleds are up to 20% heavier. Twenty percent. Maybe more. How could these sleds compete with something like an MXZ in any way? I can't think of one selling point besides smell. I don't even own a Doo and don't intend to buy one any time soon, so this is not brand bias, but this 4 stroke thing just doesn't make sense to me. Maybe for fuel efficient touring, maybe for workmobiles and ski resort type duty. But performance riding?
Where I sled: Pontiac Lake (SE Lower)/Northern Lower Michigan
Not all of us ride in the mountains full time, in fact, comparison wise, darn few of us do. The rest of us ride in the midwest and east - so it's not just about climbing for us. The 4 strokes fill the same bill as the big tripples used to. The guys coming off those don't even notice any extra weight - usually because because there isn't any. What they do notice is the current, much more sophisticated suspensions and chassis that are available. You can't compare a 600 class lightweight to a 4s, not yet anyway. Compare apples with apples. Like make sure both sleds you are comparing have elec. start and reverse. Compare the weight of a 2s cruiser to a similar 4s cruiser, or an Apex to a top of the line big Cat or Doo. They don't line up all that bad....
It's not just about low end power, it's about immediate power, without waiting for the motor to backshift, build rpm, heat up the pipe, and open the power valves to build up a head of steam. With a 4s, you don't need to listen to the engine screaming all the time so it can stay on the pipe and backshift fast enough to lift the front end at will at nearly any speed, to have full power available NOW!
You want to 4s on a budget? Look around. Try on an RX-1. With a few mods/parts swaps, that can make a pretty decent performance cruiser. A mountain climber......no. A hill climber or powder sled? Still no. Maybe a 660T?
I'll concede to the fact that there is still turf where the 2s does a nicer job - mostly where weight is critical. Off trail, jumping, and in big bumps for example. My sled has a pretty serious suspension under it, and does very well for what it is, but is no comparison to a sled with similar suspension components and 100 lbs less weight. But for the normal stuff I see/need it for on an average weekend, there is no sled I'd rather have.
Picture is from a standing start, butt on seat, feet in the wells. Another darned ol heavy 4 stroke.....