How long can a 2 cycle engine last?

[Mafesto]

We clearly prefer the power/weight ratio of the 2 stroke, but I find it un-acceptable to plan a rebuild at 3000 miles.

When I was young, the life of a vehicle was considered 100,000 miles. Now it is nothing to double that.
In the 90's a sled engine could easily run 6,000 plus miles, our beloved high strung 800's run half of that.

What are the root causes of failures?
Or maybe a better question would be...What would help these engines last considerably longer?

Increase oil consumption? Are they using too little oil to pass EPA restrictions?

Detune? Would an engine run twice as long with 10% less output?
For example, the SeaDoo PWC have an Eco mode (different mapping). The machine is in this mode by default at start up, and can be change by the push of a button.

Too light? Where could structure be increased that would add the most reliability?

I do not buy into blaming EPA because look at the outboard engine industry playing by the same rules and their 2 cycle reliability is not an issue.

Is it time to reconsider the 2 stroke triple? Perhaps that engine would be no better?

Having to rebuild the engine at 3000 miles on a $14,000 machine is not acceptable & becomes less acceptable as MSRP increases.
I think the 4 cycle will be our future if we cannot improve the 2 cycle.

 

[rmscustom]

I'll keep the current power to weight ratio we currently have and put pistons and rings in every 2000 miles.

 

[kraftymike]

I am anxious for everyone to throw their hat into the 4-stroke arena and start pushing each other. I would love to have a sled I could ride for 3-4 years after I got it set up to my liking and know it was reliable every time I took it out. I had the chance to ride with Laird of Powerhouse Customs in BC. They are building a custom 4130 tube chassis very similar to a Pro and dropping a Turbo Apex or Nytro motor into them. These things ripped and were very agile. It is possible.

http://powerhousecustoms.ca/

 

[Drifter]

05 m7 9000 miles just put a top end in. Hopefully crank is good for another 9000 miles.

I think the arctic cat 800 is good for over 3000 miles. The Polaris is not haven't seen any that get rode hard get over the 2000 mile mark. Seen sOme good miles on skidoo 800 but then you need to repack the crank.

I hope
Four stroke isn't the answer I have yet to ride a stock 4-stroke that I would trade my Polaris for.

 

[89sandman]

i have had 2 stroke sleds with over 10k on them and the motor was never opened. back east where they put on mega trail miles it happens all the time. having said that a 2 cylinder 4 stroke putting out at least 160-170hp in a well balanced sub 450 pound chassis, not the nose/top heavy pigs they have now, would to me be the ultimate tree machine. tons of torque, silky smooth powerband, that would last with less maintainence. but the key to this happening is the twin engine. there is a reason why there are no tripple 2 strokes being produced.

if yami can mate 2 250 cylinders together and get the phazer why not mate 2 450 cylinders and come out with a real mountain engine??? the phazer is 80 hp so seems the dual 450 engine could easily hit the 160hp mark. i've ridden 2 strokes all my life but the engines reliability is not advancing with the technology. i put 2-3k miles a year on my sled, seems silly to have to worry about it after just one or 2 years. i really do think that in the next few years the 4 stroke engineers will actually start to listen to what the mountain masses want and put out a competitive lightweight, balanced machine. no one wants to hear about heated seats and power steering!!!

if not they are destined to become obsolete, just ask yami how thier sales have been doing the last few years. they pulled good numbers when they first went fourstroke. the new thing on the block. a lot of people lived the hype about weight doesn't matter. after time riders realized that weight does matter. once the newness wore off peeps could see that manhandleing a ill mannered heavy machine all day gets old quick. but yami's bussiness plan has always been build one thing and then beat it into the ground. they have stayed true to that montra, they are ever faithful.

so now i have told the manufacturers what they need to do. build my machine and they will come. i know i'm tired of spending 12-13k of my hard earned dollars on a machine thats life expectancy isn't even a quarter of what it should be. build it, continue to refine it, and not only regain market share but take it over, its that simple

 

[Mafesto]

a 2 cylinder 4 stroke putting out at least 160-170hp in a well balanced sub 450 pound chassis,

Why does it have to be a twin?
The reason I ask this is that I HAVE A 1000 Prowler that makes fewer than 70 ponies (BRP's new Maverick barely tops 100 ponies)
While an Apex makes what 150 HP?
I agree that the 450 thumpers make gobs of power, however they are probably shorter lived than our 800 2/s, are they not?

I don't care if it is twin, trip or 4 cylinder as long as the weight is acceptable.

 

[Mafesto]

I just came in from a ride.
I was riding alone and spent most of the ride thinking about this thread.
When I would run at full throttle I would consider how much life longevity I was extracting from the engine. This takes a certain amount of fun out of the equation.

On average I ride 10 days/winter. about half of that is in the mountains & half here in the flats.
I would have no problem at all running a 4/S here, but keep buying a 2/s to have a better machine in the mountains.
If I ever have a good experience with a 4/s in the mountains I will make the switch & NEVER look back.

 

[89sandman]

Why does it have to be a twin?
The reason I ask this is that I HAVE A 1000 Prowler that makes fewer than 70 ponies (BRP's new Maverick barely tops 100 ponies)
While an Apex makes what 150 HP?
I agree that the 450 thumpers make gobs of power, however they are probably shorter lived than our 800 2/s, are they not?

I don't care if it is twin, trip or 4 cylinder as long as the weight is acceptable.

balance and weight. fourstrokes are nose heavy and unbalanced because of all the engine weight. a smaller light 2 cylinder engine negates both these problems at once. with a little engineering the big twin could easily be made as reliable as any 3 or 4 cylinder. don't see them being able to ever have as good of balance as a two stroke twin with big engine mass.

 

[TimG]

If there were truly high performance 4 stroke engines being used in snowmobiles, the cost of ownership would go through the roof. Ask anybody who rides a 450 how much it costs to maintain compared to a 250 2 stroke. I love my 450, just a fact.

Sure, you should put a piston in the 2 stroke every 15 hrs. or so (some 125 manuals state every 2 hours!), but it's cheap. The 450 still needs a piston periodically, plus valves, head grinding, cam chain, etc. In the motocross world, everyone is decrying the fact that 4 strokes have increased the cost of racing so much for amateurs that families can't afford it anymore. And when you don't do the maintainence on a 450 or 250f regularly, unlike a 2 stroke, nothing happens- then it all happens at once: catastrophic failure. Yamahas are the worst (expense wise)- my buddy's bike needed $3000 in parts alone when the engine went (Canadian parts pricing).

The power per cc of a two stroke cannot be matched by a 4 stroke, and neither can the power to weight ratio. And as I understand it, some of the DFI two strokes run cleaner than the 4s, so what advantage is there? Power spread? Yes, it's great and all, but it's hard to see the advantage of the 4 stroke power spread overshadowing their horrendous weight disadvantage in the big picture. And don't forget, whatever ingenious weight-saving technologies are applied to reduce the weight of a 4 stroke can be used on two strokes as well, so it seems that the 4 stroke will always, unfailingly, be at a disadvantage.

Then there are other things that come into play, such as rotational inertia/ gyroscopic effect of the 4 stroke, which makes them feel heavier and less prone to change direction than a two stroke of the same weight. As well, in the bike world, it's well known that 2 strokes get on top of the sand better, feeling more "lively", whereas four strokes (even really light ones) tend to plow through it. Nobody really understands this, but it's theorized that it's due to the power coming every second stroke rather than every fourth. Seems like this would be an even bigger deal on snow.

I'm a big fan of 2 strokes, in case it wasn't obvious.

 

[89sandman]

i've been a 2 stroke guy all my life and love them dearly. but i can see the writing on the wall, thier days are numbered. nobody is stopping people from building or racing 2 strokes but in motorcycles thier time has passed as it to will be in snowmobiling. the time will come when the weight advantage of the 2 stroke has been minimalized to such an extent that its advantage will no longer exceed the benefits of the 4 stroke. i am a 2 stroke lover and will ride one until that day comes, but when it does i'll be switching over.

as far as price goes, is a $5000 poo motor cheap? when they break a piston skirt at 1000 miles and put a whole through the block is that any less of a catastrophic failure?

 

[TimG]

i've been a 2 stroke guy all my life and love them dearly. but i can see the writing on the wall, thier days are numbered. nobody is stopping people from building or racing 2 strokes but in motorcycles thier time has passed as it to will be in snowmobiling.

The only reason that 4 strokes took over in MX is because the AMA gave them an extremely unfair advantage in their pro racing format. (450 4 stroke against 250 2 stroke) A couple years ago, they reviewed the rules to see whether they should allow 250 4s against 250 2s, and as I understand it, the manufacturers all threatened to pull out of racing if that happened, because they knew it would be a slaughter.

What about the outboard boat motor world? 4 strokes are readily available, but have they taken over? I honestly don't know much about boats, but when I look at the size of a honda outboard in relation to it's horsepower rating, I can't imagine it being desirable in a performance application. Does anybody have input here? What are the state of two strokes in the outboard world? Dying? Dominating?

If the problem is that 2 strokes pollute, DFI= problem solved. 4 strokes are the dirtier engines now.

 

[89sandman]

the 450 does not really have a hp advantage over a 250 two stroke, the 2 stroke fires every time the piston hits tdc, the 4 stroke every other. the real advantage is in torque. each for thier cc size produce close to the same amount of hp. so a 250 4 stroke produces about the same hp as a 125 2 stroke.

 

[Mafesto]

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What about the outboard boat motor world? 4 strokes are readily available, but have they taken over?

We sell approx. 50 outboard engines each year. 100% 4 cycle. We sell Yamaha & Mercury, both of which offer 2/s DI.
I imagine it's been over 10 years since we've sold a 2 cycle.

 

[summitboy]

Polaris=300km, SkiDoo=3000km, 300HP Turbo Yamaha=20,000+km LOL. Funny but so true !

 

[TimG]

the 450 does not really have a hp advantage over a 250 two stroke, the 2 stroke fires every time the piston hits tdc, the 4 stroke every other. the real advantage is in torque. each for thier cc size produce close to the same amount of hp. so a 250 4 stroke produces about the same hp as a 125 2 stroke.

The 450 and 250 four strokes have a stupendous, mind blowing power advantage over two strokes. It's absolutely ridiculous that 450s are allowed to race against 250 two stroke bikes. It's such a huge difference in power that when you ride them, you instinctively question the sanity of the rulemakers. A 450 is far closer to a 500 two stroke than a 250.

Anyways, the whole point is that with bikes, there was a reason for the change to four strokes. You'd have to be crazy (or a hero) to race a 125 against a 250f competitively. Weight difference isn't that great with a single cylinder, lots of R&D money has gone towards lightweighting the heavy four strokes, and unlike a sled, they can retain the use of a manual starter.

With sleds, it's different. Nobody cares about engine sizes, classes, or rules. Mountain sledders care about 3 things: power, weight, and cost. We're a very performance oriented bunch. It's going to be a real uphill battle for the four strokes.

As an aside, there are many credible people who claim that MX will soon return to the two stroke. We will see.

 

[Mjunkie]

I'm convinced all snowmobiles will eventually be 4-strokes. Yes there is a clean 2-stroke now, but the reliability of the 4-stroke and how 4-strokes are so much easier and forgiving when tuning will overpower the clean 2-stroke appeal from a manufacturers standpoint. The problem imo with getting the same power to weight ratio in a 4-stroke snowmobile is in the transmission. They can make a very high performance 4-stroke motor close enough to the weight and power of a similar 2-stroke but to do it, the motor has to turn 12k or more rpm. Just look at the MX bikes, bullet bikes, nascar, or formula 1 to see that. That's fine and great except that current snowmobile clutches cannot turn that fast and work properly or reliably. Anyone who owns a cat knows all about clutch failures already at 7k to 8k in rpm . I think yamaha has a gear reduction to solve that problem (I'm not personally familiar with them but that is what was explained to me once), and of course that adds weight and especially rotating mass weight (the worst kind). So snowmobiles need a new transmission imo to make the switch possible.

As far as reliability in snowmobile motors, they have gotten better, not worse over the years imo. One problem in taking a motor that is currently in a motorcycle for example and putting it into a snowmobile is that it has to be beefed up since motorcycles don't have such a constant drag on them a snowmobile does. Let's face it, a snowmobile motor has to work hard ALL the time to turn a track in snow compared to a tire on the ground. That puts an extra strain on any motor originally designed for a bike or car. So there are things to overcome but eventually they will, and until they do, there will be a market for 2-strokes, and as long as there is a market, companies will make them and the complete switch won't come.

 

[PJ-Hunter]

Polaris=300km, SkiDoo=3000km, 300HP Turbo Yamaha=20,000+km LOL. Funny but so true !

Polaris, 417 pounds but more fragile than an egg and a ticking time bomb.

Skidoo, 430 pounds, but makes awesome stock power and has a pretty bullet proof motor. I have an 09 that had 900 miles on the motor then I boosted it and added another 1100 miles and the compression is just as tight as it was new. why? I got rid of the conservative oil injection and premix. You can get a 2s sled to run forever if you maintain, tune properly and take care of it. Meaning, check oil, coolant, belts after every ride. My 2003 Honda CR250r had more miles than I can count and never a new piston. I switched to the KTM 450f because of suspension and the powerband is way better riding in the steep narrow trails high in the Rockies. Fuel consumption is better too. I can ride 80-100 miles a day on one tank but had to carry and extra liter on the 2s.

 

[snowmobiler]

fresh'n up engine at 3000 or ride a porky 4s groomer

 

[Xrider]

If there were truly high performance 4 stroke engines being used in snowmobiles, the cost of ownership would go through the roof. Ask anybody who rides a 450 how much it costs to maintain compared to a 250 2 stroke. I love my 450, just a fact.

Not true and I hear this all the time. My 450 Yamaha has been totally bullet proof. Regular oil changes and that's certainly not "through the roof". Takes maybe a half hour to change the oil myself. I quit checking the valves after I realized it was a total waste of time when they are in spec. every single time. I ride alone a lot because I have total confidence in this bike, it's never so much as even burped. AND it will pull your arms off. I often think of it like a 200 hp snowmobile that lasts forever. I can't wait for Yamaha to get the weight down on the chassis, I'll be first in line.

 

[snowhawkaddict]

Laughing gas!

http://www.youtube.com/watch?v=WT8-CkgiLJY
Thar she blows!
http://www.youtube.com/watch?v=326e76mf2hI
Blah, blah, blah.
http://www.youtube.com/watch?v=_P2CAhL0fjk

http://www.youtube.com/watch?v=JhUrKws78TE




Pretty god laugh timing was retarded.






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