I was looking at my current issue of Maxxim and it has advertised the New 2011 Polaris 800 snowmobile, it has a 795cc two stroke, doesnt say if its a twin, but I imagine it is. 0 to 80 in under 4 seconds. Now imagine that in a Sportsman or better yet a Outlaw. Just sign the waiver when you pick it up. I could never figure out why Polaris never applied their two stroke technologies into the atvs. They started out with two stroke 250, 350 and then a 400(that ran like scalded dogs). Then went four stroke. Most of the new generation doesnt even know what two strokes are capable of. It would be interesting.
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Why doesnt Polaris mix atvs with snowmobiles?
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I went camping with friends a caouple of years ago (I hate sleeping on dirt in the cold, we have houses). Ok now that I have that out of the way. AA friend of mine had another friend who brought an older honda, or polaris 2 stroke 4 wheeler. When you can get it in the powerband it's great, but slow twisting narrow trails lined with trees it just bogs down. A 4 stroke has a much flatter i.e. larger torque curve giving you much better all-around useablility.
Panzerman
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But the Yamaha Bashee is such a Great seller. Yes, suitability for woods riding isnt there, but its not for alot of the high performance quads with a clutch. I am just surprised Polaris doesnt attempt to market a engine, they already have, instaed of paying KTM to supply thier motors. Basics are that a two stroke makes 1.5 times the horsepower per size and is much lighter and alot simpler. I just read a article that two strokes are making a comeback, but with Direct inject fuel to control emmisions, with a onboard computer that does 8000 calculations per second. So although they may be two strokes, they will unfortunatly probably lose the simplicity and cheapness to rebuild them.
Seems to me there has always been a reluctance on the part of ATV manufacturers to make and market a really fast quad and I don't know why. Factories to this day put much higher tuned 4stroke engines in their dirt bikes than their quads, you would think it would be the other way around.
I raced a 2stroke Suzuki Quadracer in a Cross Country series for several years and they are a handful in the woods. They require more rider skill and finesse than the typical 4 stroke race quad. Ultimately I switched to a Polaris Outlaw with the KTM engine because repair parts became a problem for the old 2stroke. I have learned to be happy with the power delivery of 4strokes, but from time to time long for the explosive nature of my old 2stroke Quadracer...especially when trying to pull off a pass coming across an open field.
I raced a 2stroke Suzuki Quadracer in a Cross Country series for several years and they are a handful in the woods. They require more rider skill and finesse than the typical 4 stroke race quad. Ultimately I switched to a Polaris Outlaw with the KTM engine because repair parts became a problem for the old 2stroke. I have learned to be happy with the power delivery of 4strokes, but from time to time long for the explosive nature of my old 2stroke Quadracer...especially when trying to pull off a pass coming across an open field.
Originally Posted By: Panzerman
I was looking at my current issue of Maxxim and it has advertised the New 2011 Polaris 800 snowmobile, it has a 795cc two stroke, doesnt say if its a twin, but I imagine it is. 0 to 80 in under 4 seconds. Now imagine that in a Sportsman or better yet a Outlaw. Just sign the waiver when you pick it up. I could never figure out why Polaris never applied their two stroke technologies into the atvs. They started out with two stroke 250, 350 and then a 400(that ran like scalded dogs). Then went four stroke. Most of the new generation doesnt even know what two strokes are capable of. It would be interesting.
I think even a waiver wouldn't cover their liability... Hitting the gas at 40mph and having the thing go over backwards would result in alot of lawsuits, and doing 100mph in 10 seconds would kill a lot of people in the woods, even guys that have ridden alot. ATV's are so prone to flipping already that doubling the HP is just to much for most people to manage.
I guess on the practical side too, the cooling system would have to be alot bigger than it is on a sled, the drivetrain would need to be beefier, the machine gets heavier, needs bigger brakes, tougher suspension, gets heavier again...
I was looking at my current issue of Maxxim and it has advertised the New 2011 Polaris 800 snowmobile, it has a 795cc two stroke, doesnt say if its a twin, but I imagine it is. 0 to 80 in under 4 seconds. Now imagine that in a Sportsman or better yet a Outlaw. Just sign the waiver when you pick it up. I could never figure out why Polaris never applied their two stroke technologies into the atvs. They started out with two stroke 250, 350 and then a 400(that ran like scalded dogs). Then went four stroke. Most of the new generation doesnt even know what two strokes are capable of. It would be interesting.
I think even a waiver wouldn't cover their liability... Hitting the gas at 40mph and having the thing go over backwards would result in alot of lawsuits, and doing 100mph in 10 seconds would kill a lot of people in the woods, even guys that have ridden alot. ATV's are so prone to flipping already that doubling the HP is just to much for most people to manage.
I guess on the practical side too, the cooling system would have to be alot bigger than it is on a sled, the drivetrain would need to be beefier, the machine gets heavier, needs bigger brakes, tougher suspension, gets heavier again...
Panzerman
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Polaris just released the New Razor with a 80hp 900cc engine. So they arent far off of the two stroke snowmobiles. Things are getting closer. Although emmisions will prevent them from ever sticking a big two stroke in. Thank you California.
I think the Skidoo E-Tec two stroke motors are very clean but very expensive too, judging by how much more they charge over a 550 fan motor in a similar chassis. The 800cc puts out 155hp which would be fairly nuts I think in a quad, getting down to 3-4lb/HP, same as a 400 motocross bike.
We had a better idea in the 90's with a 800cc Polaris watercraft engine in an old Honda Odyssey. It was awesomely fast, that motor was super torquey at any speed.
Even that old motor had a really trick computer controlled multi strike ignition system.
Even that old motor had a really trick computer controlled multi strike ignition system.
People don't want a quad that will burst into flames when they are out in the bush.
They also want to get more than 5000 miles out of them.
That's why they are all 4 strokes.
If you look at where snowmobiles are heading, it's into a 4 stroke future.
Many 2 stroke lovers are jumping ship and not looking back.
They also want to get more than 5000 miles out of them.
That's why they are all 4 strokes.
If you look at where snowmobiles are heading, it's into a 4 stroke future.
Many 2 stroke lovers are jumping ship and not looking back.
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Quote:
Seems to me there has always been a reluctance on the part of ATV manufacturers to make and market a really fast quad and I don't know why.
They have their hands full now fighting all the government regulations on safety. Remember what happened to 3-wheelers? They run them off the market and if the oem starts putting out ATV's that are hopped up, more government wrath will come down on them and they will be fighting in court. Its never the fault of the user, it the fault of the oem for selling it.
All to often its kids (under 18) that end up of dieing or getting severely injured on a ATV's. A few years back we had two local 10 yo's killed when they hit head on on a trail, both going at a high rate of speed. Look at what happened to the Rhino when some child was killed in a rollover. All the blame was laid on Yamaha and why some young kid was allowed to hot rod around with a toddler on the utv was never the issue.
Seems to me there has always been a reluctance on the part of ATV manufacturers to make and market a really fast quad and I don't know why.
They have their hands full now fighting all the government regulations on safety. Remember what happened to 3-wheelers? They run them off the market and if the oem starts putting out ATV's that are hopped up, more government wrath will come down on them and they will be fighting in court. Its never the fault of the user, it the fault of the oem for selling it.
All to often its kids (under 18) that end up of dieing or getting severely injured on a ATV's. A few years back we had two local 10 yo's killed when they hit head on on a trail, both going at a high rate of speed. Look at what happened to the Rhino when some child was killed in a rollover. All the blame was laid on Yamaha and why some young kid was allowed to hot rod around with a toddler on the utv was never the issue.
To manage peaky two stroke power, a dual range transmission would work. Low range for tight woods riding. High range for open fields/desert conditions.
As much as I like two cycle engines, utility type ATVs are not a place for them. It's like trying to use a race horse to pull a lumber wagon. Explosive power does not go well with big rocks and trees.
As much as I like two cycle engines, utility type ATVs are not a place for them. It's like trying to use a race horse to pull a lumber wagon. Explosive power does not go well with big rocks and trees.
Originally Posted By: Mike_dup1
Quote:
Seems to me there has always been a reluctance on the part of ATV manufacturers to make and market a really fast quad and I don't know why.
They have their hands full now fighting all the government regulations on safety. Remember what happened to 3-wheelers? They run them off the market and if the oem starts putting out ATV's that are hopped up, more government wrath will come down on them and they will be fighting in court. Its never the fault of the user, it the fault of the oem for selling it.
All to often its kids (under 18) that end up of dieing or getting severely injured on a ATV's. A few years back we had two local 10 yo's killed when they hit head on on a trail, both going at a high rate of speed. Look at what happened to the Rhino when some child was killed in a rollover. All the blame was laid on Yamaha and why some young kid was allowed to hot rod around with a toddler on the utv was never the issue.
X2. It is always sad to hear of some unfortunate person being hurt in the enjoyment of a recreational product. Product liability has a big influence on manufacturing decisions and product offerings. People need to take more responsibility for their actions...unfortunatly we live in a very "litigious society" that goes for the deep pockets in court...and ultimately we all pay the price.
Quote:
Seems to me there has always been a reluctance on the part of ATV manufacturers to make and market a really fast quad and I don't know why.
They have their hands full now fighting all the government regulations on safety. Remember what happened to 3-wheelers? They run them off the market and if the oem starts putting out ATV's that are hopped up, more government wrath will come down on them and they will be fighting in court. Its never the fault of the user, it the fault of the oem for selling it.
All to often its kids (under 18) that end up of dieing or getting severely injured on a ATV's. A few years back we had two local 10 yo's killed when they hit head on on a trail, both going at a high rate of speed. Look at what happened to the Rhino when some child was killed in a rollover. All the blame was laid on Yamaha and why some young kid was allowed to hot rod around with a toddler on the utv was never the issue.
X2. It is always sad to hear of some unfortunate person being hurt in the enjoyment of a recreational product. Product liability has a big influence on manufacturing decisions and product offerings. People need to take more responsibility for their actions...unfortunatly we live in a very "litigious society" that goes for the deep pockets in court...and ultimately we all pay the price.
Panzerman
Thread starter
Originally Posted By: bsigg
People don't want a quad that will burst into flames when they are out in the bush.
They also want to get more than 5000 miles out of them.
That's why they are all 4 strokes.
If you look at where snowmobiles are heading, it's into a 4 stroke future.
Many 2 stroke lovers are jumping ship and not looking back.
Boy, you have taken the new age koolaide. First of all, I dont know of one quad that has 5000 miles on it, the entire quad self destructs around the motor, I seldom see quads that hqve over 2000 miles on them, I have one that has 2700 and it is all original and a rarity, to be still original at that milelage, they get put thru alot of abuse. It is a two stroke too. A two stroke will last just as long as a four stroke, make more power and require less maintence along the way, they were replaced because of pollution and people lack of understanding that it must have a diet of engine oil, where most people arent even responsible enough to keep oil in a four stroke.
People don't want a quad that will burst into flames when they are out in the bush.
They also want to get more than 5000 miles out of them.
That's why they are all 4 strokes.
If you look at where snowmobiles are heading, it's into a 4 stroke future.
Many 2 stroke lovers are jumping ship and not looking back.
Boy, you have taken the new age koolaide. First of all, I dont know of one quad that has 5000 miles on it, the entire quad self destructs around the motor, I seldom see quads that hqve over 2000 miles on them, I have one that has 2700 and it is all original and a rarity, to be still original at that milelage, they get put thru alot of abuse. It is a two stroke too. A two stroke will last just as long as a four stroke, make more power and require less maintence along the way, they were replaced because of pollution and people lack of understanding that it must have a diet of engine oil, where most people arent even responsible enough to keep oil in a four stroke.
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Panzerman
Thread starter
Originally Posted By: boraticus
To manage peaky two stroke power, a dual range transmission would work. Low range for tight woods riding. High range for open fields/desert conditions.
As much as I like two cycle engines, utility type ATVs are not a place for them. It's like trying to use a race horse to pull a lumber wagon. Explosive power does not go well with big rocks and trees.
Polaris actually made a line of utility quads with two strokes in them and they were quite powerful and controlable. You are correct in that transmissiond such as, low and high range, plus the jetting and head design. The Polaris trailblazer(sport quad) and the Polaris trailboss(utility) have exact same engines, 250 cc two stroke, except for the head design. I have both models and have switched the heads and its unbelievable the difference in torque, by just switching the heads. It creates alot more useable power for work.
To manage peaky two stroke power, a dual range transmission would work. Low range for tight woods riding. High range for open fields/desert conditions.
As much as I like two cycle engines, utility type ATVs are not a place for them. It's like trying to use a race horse to pull a lumber wagon. Explosive power does not go well with big rocks and trees.
Polaris actually made a line of utility quads with two strokes in them and they were quite powerful and controlable. You are correct in that transmissiond such as, low and high range, plus the jetting and head design. The Polaris trailblazer(sport quad) and the Polaris trailboss(utility) have exact same engines, 250 cc two stroke, except for the head design. I have both models and have switched the heads and its unbelievable the difference in torque, by just switching the heads. It creates alot more useable power for work.
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What's the difference in the heads? Is it head volume, shape or squish band.
I removed .030" from the squish band on my RD350 heads and that made a considerable improvement in performance. Better power and more efficient exhaust gas flow which contributes to improved engine cooling.
I removed .030" from the squish band on my RD350 heads and that made a considerable improvement in performance. Better power and more efficient exhaust gas flow which contributes to improved engine cooling.
There are a number of issues at work here.
First of all, unless you have sampled a modern fuel injected (preferably DI), power-valved, reed valve induction, computerized two-stroke, you really have no idea how good a two-stroke can be. Deespite receiving comparatively little development money compared to four-strokes, the newest state-of-the-art two-strokes (Bombardier's E-TEC desing beign the best examples) are economical, powerful and clean with a very linear power delivery.
Also, in some ways, two-strokes are penalized due to their higher power potential, often being called upon to compete with four-strokes while giving up as much as a 50% displacement advantage (have a look at the displacement forumlas for motocross to get an idea of the overwhelming advantages held by four-strokes). Virtually all of the so-called peakiness of two-strokes comes from the state of tuning required to extract the impressive power figures from two-strokes. Imagine tuning down a Polaris 800 snowmoible engine from its present 150 hp level to the power level of an ATV engine, say 70. The resulting engine would have a powerband as wide as the Great Plains. Need further proof, have a look at an Evinrude E-TEC boat engine compared to a four-stroke competitor (the marine engines being much more mildly tuned, the E-TEC hand the four-strokes their respective asses in most cases).
Alternatively, getting similar specific outputs out of four-strokes (ie. @ 200 hp/L), curiously enough, results in four-strokes that are.... cammy. Look at a modern 600 cc superpsort motorcycle as an example. They have to rev them over 15K to get the kind of numbers 600cc two-strokes get at 8000 rpm. This further proves that, contrary to popular belief, four-strokes do NOT produce more torque (if they did, those little 600s wouldn't have to spin so high now would they?)
One place where two-strokes still fall short is, generally speaking, in terms of reliability and logevity; an engine with its piston getting heated every stroke is simply not able to last as long as, or run as reliably, as one whose pistons get heated every second rotation.
DI two-strokes are more fuel efficient, more powerful, lighter, cheaper to produce, easier to maintain than cammers. Sadly, until people's outdated perceptions change, the four-stroke will always hold the upper hand (notably on the sales floor, where it matters most), based largely on false or outdated facts. So, while two-strokes offer numerous advantages, particularly in anything approaching a high-performance application, no one will venture out to build them if they sit in showrooms collecting dust, and that is the ultimate reason.
First of all, unless you have sampled a modern fuel injected (preferably DI), power-valved, reed valve induction, computerized two-stroke, you really have no idea how good a two-stroke can be. Deespite receiving comparatively little development money compared to four-strokes, the newest state-of-the-art two-strokes (Bombardier's E-TEC desing beign the best examples) are economical, powerful and clean with a very linear power delivery.
Also, in some ways, two-strokes are penalized due to their higher power potential, often being called upon to compete with four-strokes while giving up as much as a 50% displacement advantage (have a look at the displacement forumlas for motocross to get an idea of the overwhelming advantages held by four-strokes). Virtually all of the so-called peakiness of two-strokes comes from the state of tuning required to extract the impressive power figures from two-strokes. Imagine tuning down a Polaris 800 snowmoible engine from its present 150 hp level to the power level of an ATV engine, say 70. The resulting engine would have a powerband as wide as the Great Plains. Need further proof, have a look at an Evinrude E-TEC boat engine compared to a four-stroke competitor (the marine engines being much more mildly tuned, the E-TEC hand the four-strokes their respective asses in most cases).
Alternatively, getting similar specific outputs out of four-strokes (ie. @ 200 hp/L), curiously enough, results in four-strokes that are.... cammy. Look at a modern 600 cc superpsort motorcycle as an example. They have to rev them over 15K to get the kind of numbers 600cc two-strokes get at 8000 rpm. This further proves that, contrary to popular belief, four-strokes do NOT produce more torque (if they did, those little 600s wouldn't have to spin so high now would they?)
One place where two-strokes still fall short is, generally speaking, in terms of reliability and logevity; an engine with its piston getting heated every stroke is simply not able to last as long as, or run as reliably, as one whose pistons get heated every second rotation.
DI two-strokes are more fuel efficient, more powerful, lighter, cheaper to produce, easier to maintain than cammers. Sadly, until people's outdated perceptions change, the four-stroke will always hold the upper hand (notably on the sales floor, where it matters most), based largely on false or outdated facts. So, while two-strokes offer numerous advantages, particularly in anything approaching a high-performance application, no one will venture out to build them if they sit in showrooms collecting dust, and that is the ultimate reason.
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Agree with a lot of what you say other than the comments about reliability being compromised due to more frequent heat exposure to the pistons.
With modern computerized, fuel injected, liquid cooled two cycle engines heat management shouldn't be that much of an issue. Two cycle reliability is likely more to do with lubrication, or, better yet, lack thereof.
A two cycle engine does not have the luxury of it's internals either being immersed in a constant oil bath or a constant feed of oil in liquid form being pumped through it as in dry sump systems. All a two stroke gets is whatever is mixed with the fuel, injected by a pump or via computerized oil injection system. At any given time during operation, there is nowhere near the same amount of oil in a two cycle engine as in a four stroke.
Bottom line is that a two stroke makes more power without the same level of lubrication. In my opinion, if two cycle engine lubrication could be enhanced to the same level that four strokes have, their durability would be improved considerably.
Not that two cycle engines aren't reliable. They are. They just don't have the same duty cycle duration of a four stroke in the same application.
In view of the above we should consider the positives that we gain in return for giving up some durability. Excellent power to weight ratio, comparative simplicity due to fewer moving parts and relatively lower cost for rebuilds. Let's not forget the intangibles such as the kick in the pants power delivery and wild sound!!
With modern computerized, fuel injected, liquid cooled two cycle engines heat management shouldn't be that much of an issue. Two cycle reliability is likely more to do with lubrication, or, better yet, lack thereof.
A two cycle engine does not have the luxury of it's internals either being immersed in a constant oil bath or a constant feed of oil in liquid form being pumped through it as in dry sump systems. All a two stroke gets is whatever is mixed with the fuel, injected by a pump or via computerized oil injection system. At any given time during operation, there is nowhere near the same amount of oil in a two cycle engine as in a four stroke.
Bottom line is that a two stroke makes more power without the same level of lubrication. In my opinion, if two cycle engine lubrication could be enhanced to the same level that four strokes have, their durability would be improved considerably.
Not that two cycle engines aren't reliable. They are. They just don't have the same duty cycle duration of a four stroke in the same application.
In view of the above we should consider the positives that we gain in return for giving up some durability. Excellent power to weight ratio, comparative simplicity due to fewer moving parts and relatively lower cost for rebuilds. Let's not forget the intangibles such as the kick in the pants power delivery and wild sound!!
Originally Posted By: bsigg
People don't want a quad that will burst into flames when they are out in the bush.
They also want to get more than 5000 miles out of them.
That's why they are all 4 strokes.
If you look at where snowmobiles are heading, it's into a 4 stroke future.
Many 2 stroke lovers are jumping ship and not looking back.
Interesting outlook.
I hate to burrst your bubble, but the mass exodus to four-strokes in the snowmobile industry has not only subsided but is now in retreat (i have seen the sales stats to back up what I am saying BTW). The biggest beneficiaries are BRP, in no small thanks to their E-TEC. One of, if the the main reason for the exodus to four-strokes has been to lose the smoke adn smell that has long been associated with two-stroke sleds. With the E-TEC, there is no smoke or smell. Plus, they are a whole lot lighter than four-strokes, and actually MORE fuel efficient. AS for the ouil consumption, the use so little that it is virtually comparable to a four-stroke when you consider the mileage between oil changes (the E-TEC burn it instead, so you save money on a filter and the labour to change it).
The world has changed, and four-strokes are no longer the only viable option for those wanting economical and odourless snowmobiles....
People don't want a quad that will burst into flames when they are out in the bush.
They also want to get more than 5000 miles out of them.
That's why they are all 4 strokes.
If you look at where snowmobiles are heading, it's into a 4 stroke future.
Many 2 stroke lovers are jumping ship and not looking back.
Interesting outlook.
I hate to burrst your bubble, but the mass exodus to four-strokes in the snowmobile industry has not only subsided but is now in retreat (i have seen the sales stats to back up what I am saying BTW). The biggest beneficiaries are BRP, in no small thanks to their E-TEC. One of, if the the main reason for the exodus to four-strokes has been to lose the smoke adn smell that has long been associated with two-stroke sleds. With the E-TEC, there is no smoke or smell. Plus, they are a whole lot lighter than four-strokes, and actually MORE fuel efficient. AS for the ouil consumption, the use so little that it is virtually comparable to a four-stroke when you consider the mileage between oil changes (the E-TEC burn it instead, so you save money on a filter and the labour to change it).
The world has changed, and four-strokes are no longer the only viable option for those wanting economical and odourless snowmobiles....
Panzerman
Thread starter
The difference in the cylinder heads on the Polaris's is the Trailboss, utility, have a deeper dish by the sparkplug hole, really deep, like a bowl, where the Trailblazers, sport quads, have no dish by the plug and are somewhat just barely dipped, just enough for the plug tip to clear the piston. makes a big difference. I know that in 1983, Yamaha developed a different head design for their Tri-moto three wheelers for the 175 two stroke, if I ever rebuild the Yamaha Dt175, I have, I am going to swap them and see the difference. I heard they give the bikes alot more Torque.
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