250 two stroke vs 450 four stroke
- Thread starter yamahas are gay
- Start date
Help Support Mini Dirt Bikes & Pit Bikes Forum:
Ever tried racing a honda 125 2 stroke, ( model was a mx or something like that,was a crap bike), but this bike had no back brakes, no 2nd gear, bent gear shifter and a broken clutch lever. Now this was scary. lol. We later gave up on it and just left it. It was also like a 1990 something bike.lol. Probably older than alot of you guys on here.
Cactus Jack
Master Spanner Spinner
- Joined
- Jan 18, 2007
- Messages
- 2,742
- Reaction score
- 53
The V-Twin needs 1200 cc to make 150 HP ...
Ducati Multistrada 1000S
The 4 cylinder 1000 makes 180 to 189 HP out of it's smaller pulses ...
Yamaha YZF 1000 R1
Ducati Multistrada 1000S
The 4 cylinder 1000 makes 180 to 189 HP out of it's smaller pulses ...
Yamaha YZF 1000 R1
bulldog93
Well-Known Member
Cactus so are you saying the 250 2t has more power then the 450 4t over two revolutions of the crank?
What I got from it was that the 250 2t is more powerful then the 450 4t over two revoltuions of the crank.
500cc over two crank revolutions = 250 2t,
450cc over two crank revolutions = 450 4t, Thus meaning the 250 2t is more powerful.
That's how I interprated what cactus has said.
What I got from it was that the 250 2t is more powerful then the 450 4t over two revoltuions of the crank.
500cc over two crank revolutions = 250 2t,
450cc over two crank revolutions = 450 4t, Thus meaning the 250 2t is more powerful.
That's how I interprated what cactus has said.
Last edited:
the 2 stroke wont make as much torque as the 4 stroke will tho, the whole power vs torque and sacrificing torque for speed applys here.
and the 2 stroke will be sucking in more fuel/air than a 4 stroke will due to the fact extra ammounts of fuel are drawn into the expansion chamber then s a shockwave from the narrowing of the expansion chamber forces the extra air/fuel back into the combustion chamber via the exhaust port, its a form of forced air induction in my book.
As seen here:
and the 2 stroke will be sucking in more fuel/air than a 4 stroke will due to the fact extra ammounts of fuel are drawn into the expansion chamber then s a shockwave from the narrowing of the expansion chamber forces the extra air/fuel back into the combustion chamber via the exhaust port, its a form of forced air induction in my book.
As seen here:
Last edited:
Cactus Jack
Master Spanner Spinner
- Joined
- Jan 18, 2007
- Messages
- 2,742
- Reaction score
- 53
Yep , they're supercharged if they've got an expansion chamber ... A picture speaks a thousand words ...
Just watch that animation counting the strokes and note how many times it burns a cylinder charge that's boosted above it's static capacity ...
Note that the additional charge is getting shoved IN by the pipe and is not "lost" and reducing the capacity as some people try to claim ... Some charge IS lost at low revs when the pipe isn't boosting ... that's why they lose pulling power at lower revs ...
Open the hatch of a pressurized sub on the surface and air will rush OUT ... But boost the pressure HIGHER outside the sub than it is inside and the story changes ... Air will rush IN thru the hatch in the opposite direction ... and fill it to a greater pressure until the pressures equalise ... That's how expansion chambers achieve supercharging ... The cylinder bore will fill to the same pressure as inside the chamber (1 cc @ 30 psi = 2 cc @ normal atmospheric pressure) ... When the pressure is boosted BEFORE the piston traps it and compresses it again ... you have supercharging ... that's why MX two strokes run low static compression ... It's only low until the motor starts and the pipe starts doing its sneaky dirty work ...
Without an expansion chamber fitted the 2 stroke will only compress the cc's that are trapped above the ports ... Until they are revved high enough to beat the bleed off ...
They are an inferior design when run normally aspirated ... that's why they're not used in cars ...
Just watch that animation counting the strokes and note how many times it burns a cylinder charge that's boosted above it's static capacity ...
Note that the additional charge is getting shoved IN by the pipe and is not "lost" and reducing the capacity as some people try to claim ... Some charge IS lost at low revs when the pipe isn't boosting ... that's why they lose pulling power at lower revs ...
Open the hatch of a pressurized sub on the surface and air will rush OUT ... But boost the pressure HIGHER outside the sub than it is inside and the story changes ... Air will rush IN thru the hatch in the opposite direction ... and fill it to a greater pressure until the pressures equalise ... That's how expansion chambers achieve supercharging ... The cylinder bore will fill to the same pressure as inside the chamber (1 cc @ 30 psi = 2 cc @ normal atmospheric pressure) ... When the pressure is boosted BEFORE the piston traps it and compresses it again ... you have supercharging ... that's why MX two strokes run low static compression ... It's only low until the motor starts and the pipe starts doing its sneaky dirty work ...
Without an expansion chamber fitted the 2 stroke will only compress the cc's that are trapped above the ports ... Until they are revved high enough to beat the bleed off ...
They are an inferior design when run normally aspirated ... that's why they're not used in cars ...
Last edited:
Hillz
WC ST Killa
O yer & 250's rock! because you only have to change the piston once a year!! unlees your a pro that rides everyday
dont be pussies. buy a 500cc smoker, you wont need to change rings or pistons in it, cause you'll be too scared to hold it tapped for long enough anyway to actually wear the rings out, and it makes more power than any 250 2t or 450 4t...
Lolz.
Lolz.
Hillz
WC ST Killa
500cc 2 stroke is for a man with a death wish!! or a man that likes to constantly vibrate...... those things are killer i was bouncing for a week after riding one
sean01
Legend Spanner Spinner
yeah 500cc 2 strokes are the go... they tend to keep the oh sht grin on a face the whole time while riding them....lol its awesome...
have you every seen one at the drags.... low 12 sec pass, very impressive considering they are designed for dirt..
YouTube - CR500 drag racing a Kawasaki 1200
oh and dont forget the hillclimb bikes
YouTube - Kawasaki KX500 Hillclimber
YouTube - Hill Climb Havoc hahahha friggin classic this one but check the bike out @ 1minute 30secs... it shows true 500cc MX bike power the way it picks speed up so fast
have you every seen one at the drags.... low 12 sec pass, very impressive considering they are designed for dirt..
YouTube - CR500 drag racing a Kawasaki 1200
oh and dont forget the hillclimb bikes
YouTube - Kawasaki KX500 Hillclimber
YouTube - Hill Climb Havoc hahahha friggin classic this one but check the bike out @ 1minute 30secs... it shows true 500cc MX bike power the way it picks speed up so fast
hondacr80r
Well-Known Member
a two stroke picks up speed alot faster than a four stroke so i recon two stroke is the best is just depends on what u like
bournie
Well-Known Member
250s arnt really any competition for a 450f
my 250f eats 250 2ts for breakfast as will any 250f
even in a drag race
they are more reliable provided you do the maintainance :coolthumb:
my 250f eats 250 2ts for breakfast as will any 250f
even in a drag race
they are more reliable provided you do the maintainance :coolthumb:
bournie
Well-Known Member
But in the end it doesn't matter what bike you have, I was flogging everyone around the natural terrain at the last ride day I went to, no one and I mean no one could catch me
and they were on anthing from 690-50
its the rider,the bike can only go as fast as the rider lets it go
and they were on anthing from 690-50
its the rider,the bike can only go as fast as the rider lets it go
its interesting you guys are comparing the 250 two stroke to the 450 four stroke where in reality motorcycling australia has just introduced the ruling that the lites riders can now race the the 250 2 stroke against the 250f as they believe that they are the equivelants in a variety of events such as superx and motox trials etc where as in enduro they 2stroke is limited too 200cc against the 250f
R.Bmini_nut
Well-Known Member
2 stroke all they way!!!!
nothing beats the feeling you get when you ride a big bore 2 stroke, it cant be described it can only be experienced.................. by those who dare to of course
nothing beats the feeling you get when you ride a big bore 2 stroke, it cant be described it can only be experienced.................. by those who dare to of course
