2-stroke VS 4-stroke

[shaidee]

Hi guys..!!

 

For distance, which bike would be a better deal, a 2-stroke, or 4-stroke?

[rejabtheman]

4-stroke lor... 2-stroke would wear u out

[shaidee]

Then for speed-wise?

[Pandoras Kitten 3]

2 strokes are noisy, inefficient at low speeds but a Y125Z or RXZ at 6000RPM is simply heaven to me - silky smooth and rapid acceleration. The high power to weight ratio is great for beginners because sometimes you need the power to get out of silly situations. (Yes I'm the opposite of every one else. I need less raw horsepower to do the things I want to do, when experienced)

 

4 strokes (at least for class 2B) save fuel, have greater torque for start/stop/cargo hauling work but on the highway they're boring and usually lose out to 2 strokes when it comes to sprinting. Depending on revs and exhaust design, 2 strokes are capable of supercharging giving them a tremendous (and fun!) boost at speed.

 

In terms of reliability, no comment on this one but usually 4 strokes have a better track record. Not to mention, don't need 2T (which adds to your running costs).

 

If you like being the first to race off from traffic lights, and want a practical commuter with high top speed, get a lightweight, cheap 2 stroke (RXZ, Y125Z). They're fun and their light weight makes them efficient (Y125Z capable of 37km/l @120kph). Power wise it's nothing fancy but consider the Y125Z is so light your horsepower per ton should be in the entry-level sports car range. 200hp/ton is better than most cars on the road!

 

If you want a reliable workhorse and don't care for the rempit stuff, then look at CG125, CBF150, Phantom, etc. They'll get you where you want to go and you can save the maintenence and petrol/2T costs for your 2A license and a properly powerful stallion (skipping the boy racer stuff ).

 

If you found a good 4 stroke with a torquey engine then you can actually ride faster than everyone else.... uphill. You can win hillclimbs due to a wider powerband and greater torque, especially if you shed some weight off the bike. For this reason, overall performance between Spark 135 and Y125Z, the Spark actually comes out ahead and is more reliable, last time I checked.

Edited August 18, 2010 by Pandora's Kitten :3

[Cracked]

by distance u mean what? touring? if singapore road, 2 or 4 stroke also can. Juz weather u wan or duwan, dats all.

[dfthd]

2 strokes have their power stroke (where fuel combusts) once every two strokes (hence, two strokes lol), while 4 strokes have theirs once every four strokes. Hence, two stroke engines generate more power over the same rev band.

[kang91]

so can I say that

 

2 strokes have higher acceleration but lower top speeds?

And 4 strokes are vice versa?

Which one has a better FC?

 

I'm a newbie in bikes~ (x_x)

[Pandoras Kitten 3]

2 strokes have a higher top speed but they produce max. power only within a very small rev range. It's nice if you have an open road, just ride within that optimal range and save fuel by getting where you need to go faster. They are 'efficient' at going fast. Issue is, if you're a newbie and scared to open the throttle (or don't know how to map out the powerband) then you will be slow.

 

4 strokes are more efficient, produce more torque (in layman's terms, the more torque you have the less you need to change gear going uphill, and more instant acceleration - no need to rev the engine to bits like a 2S). Cheaper to run, just change oil, put fuel and bike is happy.

 

A word of warning - there are some small 4 stroke cubs that have absolutely -no- power at all. 1st gear full throttle still moving off at ah pek walking speed. Do some market research first :3

[niteblade]

so can I say that

 

2 strokes have higher acceleration but lower top speeds?

And 4 strokes are vice versa?

Which one has a better FC?

 

I'm a newbie in bikes~ (x_x)

 

2strokes. higher top speed, faster pickup BUT lousier FC

 

4 strokes. lower top speed, slower pickup BUT better FC

[KeraKing]

for distance e.g bedok wland.. 2stroke better..

but sg-kl.. 2 stroke riskier..

[KeraKing]

better as in ride more shiok..

but 4 stroke oso can lah.. modern cub can reach 130-140..

[naim]

how about sumting like rs250 compared to a s4?

[Pandoras Kitten 3]

Theoretically a 250cc 2 stroke is like a 500cc 4 stroke because you're exploding things twice as frequently for the same RPM. However in the real world friction losses, engineering complexities and imperfection downs that ratio a bit.

 

The effect is that while the RS250 can be faster than the S4 (assuming same weight, not caring about gearing, tuning, rider skill etc) in a certain range of RPM, in terms of overall performance the S4 may win out due to wider powerband, greater torque, ending up faster in real world conditions. And doesn't need 2T.

[MIGHTY MAX]

Back in 1998-2001 i used to race on CBRR/RVF in PG under cat 400cc below...

Well, 250cc is very fast....Yamaha SP, PGM...were very good in corner ....to match them...u really need to build the bike....

 

As for road...4stroke of couse///

[KeraKing]

how about sumting like rs250 compared to a s4?

 

rs250 for toy, s4 for transport.

[rocklobster]

2 strokes have a higher top speed but they produce max. power only within a very small rev range. It's nice if you have an open road, just ride within that optimal range and save fuel by getting where you need to go faster. They are 'efficient' at going fast. Issue is, if you're a newbie and scared to open the throttle (or don't know how to map out the powerband) then you will be slow.

 

4 strokes are more efficient, produce more torque (in layman's terms, the more torque you have the less you need to change gear going uphill, and more instant acceleration - no need to rev the engine to bits like a 2S). Cheaper to run, just change oil, put fuel and bike is happy.

 

A word of warning - there are some small 4 stroke cubs that have absolutely -no- power at all. 1st gear full throttle still moving off at ah pek walking speed. Do some market research first :3

 

so assuming im riding a SP right now, how do i map out the powerband of my bike to know its optimal rev range?

[SlowButSteady Bro]

2 strokes are good for short or medium haul.4 strokes are good for long distance.

Compared cc with same cc,125 2 stroke,Better acceleration up to top speed but owner must really know how to maintain the bike for optimal performance.I used to service my block/change gasket once a year to maintain the performance.For 4 stroke 125cc decent acceleration but poor on high speed but maintenance wise its slightly cheaper.What you need to worry is the Engine oil and oil filter for new bikes.One of my cousin and his friends really test the endurance of small displacement 4 stroke sport bikes suchs as the R150 from SG to Perak with minimum stop.Surprisingly the R150 can really maintain 100-110kmh on highways from JB-Melaka without stressing nor overheat which i believe its quite impossible for a 125cc 2 stroke to achieve.So they're pros and cons,Story will never end.

[Pandoras Kitten 3]

so assuming im riding a SP right now, how do i map out the powerband of my bike to know its optimal rev range?

 

You'd more or less use your "butt dyno" - since 99.99% of us in SG don't have access to an actual test facility that can support small cc bikes. Along with use some scientific knowledge of your engine characteristics.

 

Just pick up the SP, ride it normally - at first you'll go slow to get used to the handling but naturally you'll enter the high rev range and notice that at a certain RPM the exhaust system starts reflecting sound waves back to compress the fuel air charge in the cylinder giving you a boost. (Note: only 2 strokes have this exhaust supercharging effect)

 

You may also notice such other things as the power valve opening (based on feedback from SP riders) affecting performance.

 

At extremely high revs the power surge tapers off as the cylinder loses efficiency (sorry no VTEC or VVT-i here :3) so in a drag race change gear before you hit this spot to ride in the optimal RPM range.

 

In normal riding you'll also notice that certain revs can be used for overtaking and that tells you things about your powerband too.

 

For 4 strokes and such small cc commuters we use, the powerband tends to be linear making the bike very easy to master (no frills = no risk when you push the limits).

 

If you do your own carb, airbox, exhaust tuning then the powerband can change quite dramatically depending what you do. However for 2 strokes the main component of it's high horsepower and efficiency within a narrow powerband is the exhaust and expansion chamber design (and power valve setting for the SP).

 

Bigger endcan = wider powerband. Oh btw, don't cut off the "stinger" part of a 2 stroke exhaust (the ugly nozzle poking out of the end) like some cub street racers do. You lose power. It's part of a highly engineered system.

[KeraKing]

2 strokes are good for short or medium haul.4 strokes are good for long distance.

Compared cc with same cc,125 2 stroke,Better acceleration up to top speed but owner must really know how to maintain the bike for optimal performance.I used to service my block/change gasket once a year to maintain the performance.For 4 stroke 125cc decent acceleration but poor on high speed but maintenance wise its slightly cheaper.What you need to worry is the Engine oil and oil filter for new bikes.One of my cousin and his friends really test the endurance of small displacement 4 stroke sport bikes suchs as the R150 from SG to Perak with minimum stop.Surprisingly the R150 can really maintain 100-110kmh on highways from JB-Melaka without stressing nor overheat which i believe its quite impossible for a 125cc 2 stroke to achieve.So they're pros and cons,Story will never end.

 

i dun think two stroke bike will have problem cruising at 110km/h..

i have ridden sp from sg to melaca cruising at 150+-/ km/h.

[Pandoras Kitten 3]

Plus SP is liquid cooled. It's more efficient than air cooling. Bike is also very light and with a sprocket selection optimised for cruising (lower rpm, higher cruise speed) you can do like KeraKing says without much worry.

[Cracked]

so assuming im riding a SP right now, how do i map out the powerband of my bike to know its optimal rev range?

 

Juz find a straight road and experiment lor. When the surging feeling come, try to notice when it dies out. Before that happens, u up gear. By doing this, u b constantly in the bike powerband so u won't lose any torque. Dun b like those heroes in yishun dam, juz anyhow whack until e redline

 

stop.Surprisingly the R150 can really maintain 100-110kmh on highways from JB-Melaka without stressing nor overheat which i believe its quite impossible for a 125cc 2 stroke to achieve.So they're pros and cons,Story will never end.

 

I have been to melaka with a few rxz buddies b4, I was on my TZM. We maintained 110-120kmh all e way.. it can b done. Onli dat ur hands b sored due to the vibration and long journey..

[takashi_ad]

4 strokes~ rock~

[swiftee]

dist wise the 4 stroke wins la

4 stroke engine usually more durable

n comfort wise i think e 2 stroke vibration will prob kill u

 

as for powerband u see when u r normally riding, at certain range of rpm u can find tt the bike pull forward more easily

tts how u aga aga find the powerband lor

[KeraKing]

dist wise the 4 stroke wins la

4 stroke engine usually more durable

n comfort wise i think e 2 stroke vibration will prob kill u

 

try cruising 150cc 4stroke at 140km/h and 150cc 2stroke at the same speed.

see which one vibrate more.. haha

[Pandoras Kitten 3]

try cruising 150cc 4stroke at 140km/h and 150cc 2stroke at the same speed.

see which one vibrate more.. haha

 

140-160 on Y125Z - bike can attain that speed quite easily downhill, with highway sprockets. Ultimate cheap short range sprinter that can beat Maserati in traffic (done before)

140-160 on Phantom - erm... don't dare to go above 100. It's a low speed traffic control vehicle

 

But if I wanted to run from SG - JB nonstop I'd take the 4 stroke (Phantom) even if I get there later. Scared the 2 stroke don't like me and stranded on highway forever

 

Use different weapons for different tasks.