Real power..
04-23-2009, 01:20 PM
#1
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Real power..
Yummy:
http://www.motorcycledaily.com/22apr...0cc2stroke.htm
If not exactly sane.
when completed, it should make 250 hp at the rear wheel and 160 ft.-lbs. of torque.
http://www.motorcycledaily.com/22apr...0cc2stroke.htm
If not exactly sane.
when completed, it should make 250 hp at the rear wheel and 160 ft.-lbs. of torque.
04-23-2009, 01:46 PM
#2
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The future is now in the snowmobile and boating industries. Do a search on the E-TEC engine. Fuel economy superior to a four-stroke, no smoke or smell, oil consumption at or below four-stroke levels (when you factor in oil changes).
Having spent considerable saddle time riding E-TEC sleds (I am editor of a snowmobile magazine), I can tell you that the two-stroke engine is far from dead. If anything, the four-stroke`s days may be numbered.....
Having spent considerable saddle time riding E-TEC sleds (I am editor of a snowmobile magazine), I can tell you that the two-stroke engine is far from dead. If anything, the four-stroke`s days may be numbered.....
05-08-2009, 10:36 AM
#6
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although four strokes last longer, the 2 strokes are much more efficient (hence why they had to build a 450 four stroke to keep up with a 250 two stroke). and as far as rebuilding them its cheap and easy. and simple. Im sure there's some way to get them to burn cleaner and keep the tree huggers happy. As far as im concerned i hope they never die!
05-08-2009, 10:47 AM
#7
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"Im sure there's some way to get them to burn cleaner and keep the tree huggers happy. "
There is, read my prior post! Here is a link to help fill you in.
http://www.ski-doo.com/brphtml/skido...h/en/Index.htm
I wrote an extensive technical overview of the E-TEC technology that appeared in our snowmobile magazine back in DEcember 2005. Unfortunately, the English version is no longer up on our Web site (guess I'll have to get our Web master to work on that...). Can send a WORD version by e-mail if anyone is interested.
To put it bluntly, this is the cat's meow. It is as clean (or cleaner) than a four-stroke, much more powerful, more fuel efficient. No smoke, no smell, ust awesome power and light weight. What is there not to like?
There is, read my prior post! Here is a link to help fill you in.
http://www.ski-doo.com/brphtml/skido...h/en/Index.htm
I wrote an extensive technical overview of the E-TEC technology that appeared in our snowmobile magazine back in DEcember 2005. Unfortunately, the English version is no longer up on our Web site (guess I'll have to get our Web master to work on that...). Can send a WORD version by e-mail if anyone is interested.
To put it bluntly, this is the cat's meow. It is as clean (or cleaner) than a four-stroke, much more powerful, more fuel efficient. No smoke, no smell, ust awesome power and light weight. What is there not to like?
05-10-2009, 08:17 PM
#8
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high performance 4 stroke engines have the same or shorter rebuild intervals then my 20+ yr old 250R. they are so ragged edge to get them to have decent performance that they are like time bombs, and talk about expensive when they do let go.
(im thinking high HP single cylinder ATV engines. motorcycle engines would be the same but theres no good comparison so everyone thinks a busa engine produces 'insane HP' fact is if there was acomparable 2-stroke in size, maybe like the one in the above article, it would walk all over the busa)
(im thinking high HP single cylinder ATV engines. motorcycle engines would be the same but theres no good comparison so everyone thinks a busa engine produces 'insane HP' fact is if there was acomparable 2-stroke in size, maybe like the one in the above article, it would walk all over the busa)
05-11-2009, 08:12 AM
#11
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A modern, DI two-stroke with variable height exhaust valves and reed induction is a truly pottent and user-friendly engine. Add in state of the art computer processing power (with a wealth of sensors) and you could build some pretty sweet streetbikes. I can`t help but wonder who`ll have the gonads to be be first to do so (KTM is reportedly close to unveiling a line of DI street-legal enduro bikes).
05-11-2009, 02:26 PM
#12
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http://dirtbike.off-road.com/dirtbik....jsp?id=332426
that engine design is based off of a late 90's design with some updates so its reasonably up to date. give that article a read if your bored.
people have also built motards out of CR500AF's and they blow the wheels off 600cc street bikes in all but pure top speed runs.
(i know that article is old, but the bike was produced in fairly limited numbers and is a fairly large 2-stroke, single cylinder though)
that engine design is based off of a late 90's design with some updates so its reasonably up to date. give that article a read if your bored.
people have also built motards out of CR500AF's and they blow the wheels off 600cc street bikes in all but pure top speed runs.
(i know that article is old, but the bike was produced in fairly limited numbers and is a fairly large 2-stroke, single cylinder though)
05-11-2009, 08:03 PM
#13
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I'd love to see 2-strokes be revisited because I love the idea of a 250lb street sport bike but I think Aprilia could get there by adapting their Supermoto 550cc bike with the V-twin in it. That said, 4-strokes are tractable. In GP racing the two stroke was developed nearly to the limit. The first year 4-strokes came into GP the two strokes (which had a weight advantage) got smoked badly. The only race where a 2-stroke managed to be competitive was Assen, Holland.
05-15-2009, 08:03 AM
#15
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I'd love to see 2-strokes be revisited because I love the idea of a 250lb street sport bike but I think Aprilia could get there by adapting their Supermoto 550cc bike with the V-twin in it. That said, 4-strokes are tractable. In GP racing the two stroke was developed nearly to the limit. The first year 4-strokes came into GP the two strokes (which had a weight advantage) got smoked badly. The only race where a 2-stroke managed to be competitive was Assen, Holland.
Same with motocross, you have 450 cc four-strokes running up against 250 cc two-strokes. Let them all run at 450 cc and you`ll see the cammers disappear in short order....
05-15-2009, 08:41 AM
#16
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I don't disagree, Ricky Carmichael managed to be dominant on a 250cc 2 stroke when everyone else was on 4-strokes. That said, a modern 450cc 4 stroke makes nearly the same hp as a 500cc 2 stroke did and is far more rideable.
The 2 stroke GP bikes didn't fail entirely because they didn't make enough hp, they failed because the 4 strokes made more hp and the bikes fully harnessed it. Despite being more powerful the 4-stroke bikes were also better on the rear tire wear.
The 2 stroke GP bikes didn't fail entirely because they didn't make enough hp, they failed because the 4 strokes made more hp and the bikes fully harnessed it. Despite being more powerful the 4-stroke bikes were also better on the rear tire wear.
05-15-2009, 09:10 AM
#17
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Tune a two-stroke down to four-stroke levels (in terms of specific output, or hp/L) and you`ll be amazed at how torquey it can be. I spent a good deal of time speaking with the head of E-TEC design at Evinrude when I was getting ready to write a a tech article about it and was amazed at what I learned. Two-strokes are shunned because of the bad name they acquired in teh old days. A modern DI two-stroke is better than a four-stroek in practically every way imagineable (except perhaps long-term longevity). Again, the problem lies in the fact that comparisons between teh two engine types amost always involve two-strokes being at a significant displacement advantage. Put them on an even footing and four-strokes don't stand a chance!
05-15-2009, 09:30 AM
#18
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2 and 4 strokes have the same rebuild intervals now, along with it being cheeper to rebuild the 2 stroke.
a properly set up 2 stroke can have more torque then the same CC (or 2x the same CC) 4-stroke.
to be on relatively equal footing in theory a 4 stroke can be 2x the cc of a 2-stroke because the 2-stroke has 2x the power cycles. (note the word THEORY)
i run relatively low tech old school ATV's with 2-strokes in them and they will MUNCH the new 4-stroke equivalent. top end and off the line. along with proper maintenance and these newfangled oils called "synthetics" there is no reason a 2-stroke needs rebuilt more often.
a properly set up 2 stroke can have more torque then the same CC (or 2x the same CC) 4-stroke.
to be on relatively equal footing in theory a 4 stroke can be 2x the cc of a 2-stroke because the 2-stroke has 2x the power cycles. (note the word THEORY)
i run relatively low tech old school ATV's with 2-strokes in them and they will MUNCH the new 4-stroke equivalent. top end and off the line. along with proper maintenance and these newfangled oils called "synthetics" there is no reason a 2-stroke needs rebuilt more often.
05-15-2009, 09:59 AM
#19
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Here are some intersting tidbits about two-strokes and four-strokes (quoted from an article I had commissioned from Kevin Cameron (Of Cycle World fame) for our snowmobiel magazine):
1) two-stroke produce 150-170 lb-ft of torque per 1000-cc of engine displacement, while the four-stroke produces 75-95 lb-ft per 1000-cc (NB: as you can see, it's not a case of "can have as much torque"!).
2) fuel consumption (using the amount of fuel that must be burned to produce one horsepower for one hour as our standard);
Carbureted two-stroke 0.65 – 0.7 lb/hp-hr
Four-stroke (either carbs or FI) 0.5
Two-stroke with DFI/SDI 0.45 – 0.5
Diesel 0.35 – 0.38
Also (back to me now), people refer to four-strokes as torquey because they generally have a flatter and more linear torque curve. Of course, highly tuned four-strokes (think F1 cars) with high specific outputs tend to have peaky curves much like a more typical two-stroke. Add the fact that two-strokes have much less mechanical drag (far fewer moving parts), very little pumping loss, weigh less and cost less to produce and I think that pretty well puts the arguments to rest, don`t you?
1) two-stroke produce 150-170 lb-ft of torque per 1000-cc of engine displacement, while the four-stroke produces 75-95 lb-ft per 1000-cc (NB: as you can see, it's not a case of "can have as much torque"!).
2) fuel consumption (using the amount of fuel that must be burned to produce one horsepower for one hour as our standard);
Carbureted two-stroke 0.65 – 0.7 lb/hp-hr
Four-stroke (either carbs or FI) 0.5
Two-stroke with DFI/SDI 0.45 – 0.5
Diesel 0.35 – 0.38
Also (back to me now), people refer to four-strokes as torquey because they generally have a flatter and more linear torque curve. Of course, highly tuned four-strokes (think F1 cars) with high specific outputs tend to have peaky curves much like a more typical two-stroke. Add the fact that two-strokes have much less mechanical drag (far fewer moving parts), very little pumping loss, weigh less and cost less to produce and I think that pretty well puts the arguments to rest, don`t you?
Last edited by mikstr; 05-15-2009 at 10:08 AM.
05-15-2009, 10:14 AM
#20
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I like the rebuild interval of my old school Honda XRs thanks. I wouldn't even think of owning one of the new hyper maintaince CRF 4 strokes and have never liked the power delivery of 2 smoke dirt bikes. But I'm only into hill climbs and trail riding. I'm not a motocross racer.
I did enjoy the time I spent on an RZ350 though. Nice tight package, but I still like the super low RMP grunt power of all the bikes I own.
I did enjoy the time I spent on an RZ350 though. Nice tight package, but I still like the super low RMP grunt power of all the bikes I own.
05-15-2009, 11:05 AM
#21
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I like the rebuild interval of my old school Honda XRs thanks. I wouldn't even think of owning one of the new hyper maintaince CRF 4 strokes and have never liked the power delivery of 2 smoke dirt bikes. But I'm only into hill climbs and trail riding. I'm not a motocross racer.
I did enjoy the time I spent on an RZ350 though. Nice tight package, but I still like the super low RMP grunt power of all the bikes I own.
I did enjoy the time I spent on an RZ350 though. Nice tight package, but I still like the super low RMP grunt power of all the bikes I own.
the point all of us are trying to make is, if a 4-stroke can do it, a 2-stroke can do it better. the problem is, and you are a direct reference to this, 2-strokes have bad and or misleading info planted in peoples heads, or info from people who havent touched a 2-stroke in 30 yrs. (no offense)
05-15-2009, 11:11 AM
#22
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No offense taken. I still ride 2 stokes in the dirt (rode my friends last weekend for instance). And I have ridden the new CRFs too. So I have recent reference points. Rebuild intervals is what I am comparing. You can't beat old XRs or any old air cooled thumper for that.
What is the rebuild interval on your wife blaster again?? I'm going to guess it's at least 4 times as often as my XRs.
What is the rebuild interval on your wife blaster again?? I'm going to guess it's at least 4 times as often as my XRs.
Last edited by Moto Man; 05-15-2009 at 11:24 AM.
05-15-2009, 11:20 AM
#23
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I picked up a 1990 Yamaha DT200R last summer (my second one; model was never imported into the US). Actually, I began looking after riding a new Yamaha WR250R test unit. The engine is the poster boy of user-friendliness; at idle you hardly hear it (quieter than the WR), you can lug it like a trials bike yet it still pumps out 32 hp on top, all the while getting over 60 mpg. Also, it is MUCH lighter than the WR.
05-15-2009, 11:33 AM
#24
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No offense taken. I still ride 2 stokes in the dirt (rode my friends last weekend for instance). And I have ridden the new CRFs too. So I have recent reference points. Rebuild intervals is what I am comparing. You can't beat old XRs or any old air cooled thumper for that.
What is the rebuild interval on your wife blaster again?? I'm going to guess it's at least 4 times as often as my XRs.
What is the rebuild interval on your wife blaster again?? I'm going to guess it's at least 4 times as often as my XRs.
my RACE prepped ported polished ragged edged 250R liquid cooled 2-stroke built for high RPM use will make it about 4 years "casual" weekend riding. again 20 year old engine (and a lot of it actually is that old) with some newer piston, bearing, and feuling tech added on.
05-15-2009, 11:34 AM
#25
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I picked up a 1990 Yamaha DT200R last summer (my second one; model was never imported into the US). Actually, I began looking after riding a new Yamaha WR250R test unit. The engine is the poster boy of user-friendliness; at idle you hardly hear it (quieter than the WR), you can lug it like a trials bike yet it still pumps out 32 hp on top, all the while getting over 60 mpg. Also, it is MUCH lighter than the WR.
10-26-2009, 02:30 AM
#29
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I'm a bit two stroke ignorant mechanically, but I had a CR125 for a few months and it was a blast to ride, lightweight yet powerful enough to climb steep sand pits hills.
I had the chance to ride a CR500 also, it just had too much torque, the rear wheel was still slipping at over 100 km/h, but it has no powerband, I was constantly hitting the rev limit.
Old two strokes don't condone lazy shifting that's for sure.
I'm very interested in test riding a DI MX.
I tried the WR-250X, too weak, but the chassis felt good trough the corners at lower speed.
I had the chance to ride a CR500 also, it just had too much torque, the rear wheel was still slipping at over 100 km/h, but it has no powerband, I was constantly hitting the rev limit.
Old two strokes don't condone lazy shifting that's for sure.
I'm very interested in test riding a DI MX.
I tried the WR-250X, too weak, but the chassis felt good trough the corners at lower speed.
12-25-2009, 02:12 AM
#30
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Ever since my first ride on a YZ 80 in the early 1980's I have been a serious 2 stroke fan! I was sick when MotoGp went 4 stroke.
If I remember correctly, in 2002 the 2 strokes also almost won at the Sachsenring. I believe that Olivier Jaque (500) was leading, Barros (500) 2nd and Rossi (990) 3rd on the RC211V. Barros tried to pass Jaque and took them both out handing the win to Rossi and the 4 stroke.
I would love to see the 2 stroke make a come back. With all the high tech DI ect... I see no reason why it shouldn't. With all the electronic trickery the MotoGp 4 strokes enjoy I don't see why some if not all could be applied to a new generation 2 stroke.
This is a great thread. I would love to take that 1100 on a ride!
If I remember correctly, in 2002 the 2 strokes also almost won at the Sachsenring. I believe that Olivier Jaque (500) was leading, Barros (500) 2nd and Rossi (990) 3rd on the RC211V. Barros tried to pass Jaque and took them both out handing the win to Rossi and the 4 stroke.
I would love to see the 2 stroke make a come back. With all the high tech DI ect... I see no reason why it shouldn't. With all the electronic trickery the MotoGp 4 strokes enjoy I don't see why some if not all could be applied to a new generation 2 stroke.
This is a great thread. I would love to take that 1100 on a ride!
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