Two vs. Four

I'm kinda looking at getting a dirt bike for mountain trail use, and I was wondering if a 2 stroke or 4 stroke would be better. Also what displacement would you all recomend. I'm mostly looking at Yammies. I've been thinking a yz-250F would be fairly good.

I think for trail riding involing hills and paths a 2 stroke would be the best the pick up is much better and they are ment for it, a 4 stroke is meant for flater riding. 4 do much better on long term over all power, you need quick fast power which you can get better from a stock 2 stroke

:dogpile: ok i saw this smiliyi had to put it on.... cmon why would i need to respent a dogpile of soemone?!?!

I am very impressed with the Yamaha WR 250F after some free mods to bring it up to YZ 250F specs. Two strokes are just too much to maintain for woods riding. I used to ride an IT 200 but it was made for trail riding and still fouled plugs on occasion and terrible on gas. Very important consideration for long distance riding. The older ITs even had two spark plugs so you could just switch the wire to the other plug when one fouled.

I might be wrong but isnt a 4 stroke much better for trail riding. ive always ben otld that with a 2 stroke if you dont keep it wound out all the time you foul many many plugs.

A 2-stroke is alot more fun because of the accerlation if you
plan on hitting the trails hard but if your going to sight see
then a 4-stroke would better suit you

yeah, if the traisl new though you cant really haul ass through it, ive done it on a 02 CR125 and the result isnt pretty, never wrecked it but S's come out of nowhere and theres BIG trees in the woods, LOL. but i did trail ride it a few times and it is fun, and they are quick little suckers, id imagine the 250 would be REAL fun. I myself am gonna go for 4 troke because although i dont mind working on my own stuff and maintaining them, I dont wanna be rebuilding top ends all the time, and then when im in there id do the bottom too just to be safe, and the guy with the 4 stroke will still be out playing.

I'm a die hard 2 stroke fan. I've been getting dumped be YZs since I was 11. The arm streaching power of a 2 stroke is hard to beat, but the new thumpers are very impressive as well, the only soultion, buy both.

I'm also a die hard 2-stroke fan. I have a seriously modified 00' YZ 125 set up for the woods and believe me its alot of fun. 2 strokes are usually a little lighter then 4's and will handle a little better in the tight stuff. They can be tricky in the woods, trying to keep the rpm's up requires a slightly more aggressive riding style where the 4's have more tractable power down low and a smoother power delivery and require a little less effort to stay in the meat of the power band. Todays 4 strokes have come a long way and are excellent trail and moto-x bikes requiring less maintenance then the 2 strokes. If you're going to be in the mountains i would go with the YZ 250f. You will appreciate the extra torque a 4 stroke has when your climbing.

Danny

i tell u what i am only a 15 yr onld guy but i know what i like and i like dirtbikes in general and i have rode the yzf400 pretty sweet it flies and it has plenty of power... you can go slow and easy and u can sweep up the races if u know how to ride and especially for the trails it is great because alot of the new 4 strokes keep up wit these 2 strokes.. with these new thumpers u can get alot of torque at the bottom and and mid range pretty much where ever want so if u need the extra boost to get over that big log to get your front wheel off the ground it is there and yes the 2 strokes are fun to ride in trails if u like to be alert and work your clutch hand alot but i would go with the 4 stoke also because u said mountains that is elevation it would probably be easy to adjust the engin to it but i dunno bout any of that.. 2 strokes can get up hills but it is still easy from what i've found with a 4 stroke becuause with a 2 stroke u get that wheel spinnnin jus to fast and the four stoke stays steady and u get a good steady ride up.. thats my two cents.... sean

I say 2-stroke all the way. It's lighter, easier to maintain (no valve train, no changing of oil), good pickup - and a sound that's music to my ears. For lots of uneven riding it's good.
A four stroke is a bit heavier, but offers better bottom end torque, but require more maintenance, and has more parts to break.
It really just comes down to preference and compromises, do you need low end torque? do want a lighter engine? Do you want to change oil? Or do you just want to mix some into the gas tank?
I'm devoted to 2-stroke power no matter what sort of machine it's in, for a single cylinder engine it's smoothness of torque, light weight, and power for displacement are hard to beat.
But that doesn't mean it's always the best choice.

2 stroke for sure I say. They are actually easier to maintain. Who cares if they foul the odd plug just wack a new one in. The power is heaps better and you can get a lot of bottom end out of a 250 or 500. Though beware a 500cc 2 stroke is only for the hard core especially a CR500. You do have to rebuild the top end a lot more often on a 2 stroke though(not as often as a dealer will tell you though) but it is very easy.
Good luck

I have to disagree 4 stroke is the only sencable solution not only do you have a decent power curve but the engine has a much longer live span. Most of the net 4 strokes out are every bit as powerful as the 2 stokes are and only slightly heavier. Go with the 4 stroke and get the good fuel economy got torque curve long engine life and quitier engine operation and no premixing.

Ok i have a 2 stroke and it is awesome in pretty much everything. The only thing i ever had to do to it to make it better at trails is gear it down to a 50 tooth sproket (for easier technical riding). Now its pretty much perfect (for me). Oh ya the gas rumor is not completly true. My 2 stroke 80 goes about 70 miles on 1.5 gallons. I know the four strokes get even better but 70 miles is alot of riding. So i say 2 stroke all the way.

I would definatly have to say 4 stroke if you are looking at mostly doing trail riding. People always say that 2 strokes are faster and everything, but my KLX 300 (which doesn't have a ton of mods) will beat a 250 off the line, and go up to about 100mph. WHile in the sand it is not as good, but on the trails, nothing beats it.

Okay folks, look at most 2 strokes these days. They are motocrossers. Race bikes, not trail machines! 2 strokes are less forgiving, less low end torque, peaky powerband and less easy to ride than a 4 stroke, especially in difficult terrain.
The 4 stroke is the better trail machine, the 2 stroke (usually) is the better race bike.

well, that 300 must be a beast, cuz Ive ridden a fairly new 200cc4, and a very new 125cc2. and the 125 smoked it off the line. also a 11 year older 250cc2 was whooping on this new 125 so I imagine a new great condition 250cc2 wouldnt give the 200cc4 a snowballs chance you know where of taking it off the line, the 4 stroke does have a better top speed though, not geared so close, which is probably a major reason the 2 stroke is so damn quick. but riding a 2 stroke in trails is so easy, you dont have to keep em wound out like lots of people tell you, of course you dont really have the slow cruising torquiness of a 4 stroke, but even imn trails, I dont wanna go slow, only if im going around a hella sharp turn or something, and even then all you do is slow a bit on the straight, point the front where you wanna go, downshift and floor it and you end up going where you wanna go.

I know I was pro-4 in the beginning but since riding more bikes Im gonna have to go to the other side, get the 2 stroke, but this is kinda old so Id bet he has a bike already...

No offence to anyone, but I still can't figure out why people say things like "cruising tourquiness." Torque, unlike what most people believe, is what makes the wheels turn. The more torque something has, the faster/quicker it will be able to travel. If you gear down a 4 stroke, it will also be very quick compared to one that has higher gears. Also, 200 cc's is not very big at all for a 4 stroke, so of course a 250 2 stroke will smoke it...that was not a very good example.

4 stroke will be the disign of the future there is no doubt about it. The 4 stroke is clean and efficent and delivers a better torque curve and the difference in weight can be made very minimal no too

i know what torque is, and I know what it does, a 4 stroke has alot more of it down low, but once the 2 stroke revs a bit it blows away a 4 stroke. I mean look at racing, a 450 4 stroke is against 250 2 strokes and a 250 2 stroke goes up to a 125 2 stroke. and by cruising torquiness I just meant when your going hella slow just cruising through a trail you are gonna be at a low RPM, whihc is where the 4 stroke has more torque than the 2 stroke, yes I made up some BS word to describe it but my point was correct. and for sure the 4 strokes are more efficient and cleaner but 2 strokes are more fun.

ok, two cents worth here. For a number of years, my preferred trail machine was a 1990 honda XR600. Big thumper, excellent low end, enough top end to keep my little mind happy, and decent fuel economy for when you are exploring those places you're not sure you should have gone. It wasn't too heavy, and the steering was pretty quick too.
I am not saying that the four strokes are for everyone, I used to race 2 stroke bikes, but, hey, we all get old.

and besides, 2 stroke vs. 4, go with four, prolong the fun for everyone.

Happy trails

i know what torque is, and I know what it does, a 4 stroke has alot more of it down low, but once the 2 stroke revs a bit it blows away a 4 stroke. I mean look at racing, a 450 4 stroke is against 250 2 strokes and a 250 2 stroke goes up to a 125 2 stroke. and by cruising torquiness I just meant when your going hella slow just cruising through a trail you are gonna be at a low RPM, whihc is where the 4 stroke has more torque than the 2 stroke, yes I made up some BS word to describe it but my point was correct. and for sure the 4 strokes are more efficient and cleaner but 2 strokes are more fun.


Haha 2 strokes don't blow away 4 strokes at higher rpm either and if you acually bother to learn anything about racing you will find that the 450 4 strokes that are against the 450 blow them away. It is true that 2 strokes can make a little more peak power for a displacement but not enough to outway the poor torque curve and all the other 2 stroke disadvantages (short engine life,emissions,premixing,bad fuel economy,noise) I have riden both 4 strokes and lots of 2 strokes and I would have to say the 4 strokes are for more fun anyway day.

For those of you who believe 2 strokes have more torque and are better than 4 strokes, why do cars have 4 stroke engines?? How come if you go to your local drag-strip, you never see 2 stroke muscle cars out there?

Just something to think about. Please don't respond unless you have something inteligent to say!!!

i'll respond on the drag strip case you cant get any power with a two stroke on the drag strip due to weight of the vehicles on the strip now you take a lighter 2 stroke bore it out and then place a four stroke next to it and yeah your gonna smoke it if they are the same (or close to the same) size and lets be real how many two stroke motorcycles out there ten years or older hasnt been bored out due to the fact that two stroke engines wear out pretty quick if you realy ride them hard

so how come in sx the yz450f beat all the 2 strokes and i would put my berger up againt any 2 stroke any day of the week its 600 ways 107kg can accelarate out of 4th from a near stand still no worries and use to do 200kph plus till somthing went wrong with the carby simple get a husaberg....:)

how come i keep fouling spark plugs. i have a cr125 and now it wont start.

Haha 2 strokes don't blow away 4 strokes at higher rpm either and if you acually bother to learn anything about racing you will find that the 450 4 strokes that are against the 450 blow them away. It is true that 2 strokes can make a little more peak power for a displacement but not enough to outway the poor torque curve and all the other 2 stroke disadvantages (short engine life,emissions,premixing,bad fuel economy,noise) I have riden both 4 strokes and lots of 2 strokes and I would have to say the 4 strokes are for more fun anyway day.

ok, but notice the displacements.

put the CRF250X or YFZ250 against thew CR250 and the YZ250. its not fait to compare a 450cc 4 stropke to a 250c 2 stroke and then say 4 stroke is better.

this has nothing to do with bikes but go look at the new etec outboards, they are 2 strokes, and they are cleaner than the 4 strokes. there is now a fuel injector, so no open exhaust port letting out fresh mix, once the exhaust port is closed the injector puts in the fuel so the WHOLE mix is compressed not part of it compressed and part of it escaping and polluting the air so bad. and theres way less parts which is why 2 strokes are alot lighter. I know the cleanliness argument here contradicts my old statement, and they usually are still way more polluting but look at the technology in the evinrudes 2 stroke, clean burning and good power, AND better economy than the 4 strokes.


and about the track scenario, just a dumb comparison. there is no 2 strokes out there because first of all your muscle car came with a gasoline V8 from the factory, how many people can pull their big block and engineer/design a 2 stroke V8 AND machine/assemble it in their garage.

I bet you someday there will be a class for custom built 2 strokes because of newer technology coming out and the power you can get out of them, but I doubt right now youd be allowed to pull up in a custom 2 stroke dragster next to a top fuel, no matter who would win someone would bitch it isnt fair and it just wont happen.

also most 4 stroke bikes (dirt bikes) arent multi valve DOHC water cooled beasts like the MX 4 strokes. there is choiuces of 4 storkes, the 2 stroke you buy, you get the CR250 or nothing, want a 4 stroke you can get a XR400 or the all mighty CRF450

The reason they find it fair to compare and race double displacement 4 strokes against 2 strokes is that the 2 stroke fires on every crank rotation instead of every other. So a 250 2 stroke makes "500cc's worth" of power in the same number of crank rotations as a 450 4 stroke. It's all in how they make the power.

but every time the mix is ignited in the 450, you have 450cc's worth of displacement making its power, even if it does fire half as often. I see your point but I still think its crap.

The reason they find it fair to compare and race double displacement 4 strokes against 2 strokes is that the 2 stroke fires on every crank rotation instead of every other. So a 250 2 stroke makes "500cc's worth" of power in the same number of crank rotations as a 450 4 stroke. It's all in how they make the power.

Different strokes for different folks. Whether you get a 4 or 2 stroke for trail or enduro riding or racing is a matter of personal preference and rider skill.

Here is something that may shed some light on the issue of 4 versus 2
from a leading Guru at Motocross Action Magazine:

Question: "Why didn't four strokes replace the two strokes years ago? It is obvious that four strokes are better."

Answer: "So much for your deductive reasoning Sherlock. In truth, the two strokes are the ultimate motocross racing engine. A two stroke engine weighs less, has fewer moving parts, has a significantly reduced maintenance cost, revs quicker, is cheaper to manufacture and produces
more horsepower per liter than a four stroke."

"If two strokes had been invented yesterday, we would be hailing their arrival as a watershed moment in engine technology. So, why are four strokes dominating now? It is a combination of pending EPA legislation to which the manufacturers must comply, me-tooism on the part of
consumers, and that the fact that four strokes are allowed under AMA rules, considerably larger displacement. Without the extra displacement, no one would be racing a four stroke today."

I 100% agree with everything he said. I was just offering an explanation of why they see fit to give the 4s a displacement advantage.

I'd still take a 4 stroke anyday. I prefer the way they make power. Like you said, different strokes....

I 100% agree with everything he said. I was just offering an explanation of why they see fit to give the 4s a displacement advantage.

I'd still take a 4 stroke anyday. I prefer the way they make power. Like you said, different strokes....

Four strokes are good bikes. I had a Yamaha YZF 426 but the maintenance costs were too high when it came time for re-doing the top end.

The most simple explanation of the 4s displacement advantage is they need it to be competitive. For example: we had a racer that got caught with an overbore kit on his YZF 250 and got bumped up to the 250 cc
class from 125cc class. Needless to say he did not not fair too well on the track against the 250cc two strokes, often getting lapped.

As to the CRF 450s and YZF 450s, they are not stock when competing against two strokes with AMA legal mods such as porting, Pro Circuit or FMF exhaust, V Force Reeds, etc which doesn't cost an arm & leg in dinero.

A box stock Honda CRF 450 or Yamaha YZF 450 cannot beat a modified two stroke 250 on a AMA type track. For proof just check out the Supercross racing results....although they are factory works bikes, the two strokes dominate. When the regular season starts they will switch over to the thumpers because they shine on hilly tracks with long strait aways but the two-strokes always surprise everyone. Lets see how James Stuart will do this year riding a Kawasaki works KX 250 against all the thumpers. Reed and Carmichael will switch over to their works thumpers.

in addition to all that, if your working on your bike at home and truck it up the hills your going to have to second guess carb jetting for altitude, if its a significant difference.... i think a four stroke would be more forgiving in this respect.

i'll respond on the drag strip case you cant get any power with a two stroke on the drag strip due to weight of the vehicles on the strip now you take a lighter 2 stroke bore it out and then place a four stroke next to it and yeah your gonna smoke it if they are the same (or close to the same) size and lets be real how many two stroke motorcycles out there ten years or older hasnt been bored out due to the fact that two stroke engines wear out pretty quick if you realy ride them hard

well, what about drag bikes? they all seem to be 4's ?

The reason they find it fair to compare and race double displacement 4 strokes against 2 strokes is that the 2 stroke fires on every crank rotation instead of every other. So a 250 2 stroke makes "500cc's worth" of power in the same number of crank rotations as a 450 4 stroke. It's all in how they make the power.

not only that but what you gain in rpms you lose in stroke and this would be a fair arguement if rpms were limitless so you realy need to compare hp torque @ redline i'm a fan of both realy, i even think diesels are cool... theres an aircraft 2 stroke diesel motor that makes 350 hp and weighs 350 pounds, (i've heard) It runs on jp1. because of worldwide availibility... i'll try to find a link for this motor... also what about akt bikes? don't they have some crazy ass motor?

ok, check this out...?
http://tec.avl.com/wo/webobsession.servlet.go/encoded/YXBwPWtiYXNlJnBhZ2U9Y29udGVudC1tYW5hZ2VtZW50L3ZpZX cmaWQ9NDAwMDMxMDY3.html
a diesel two stroke motorcycle?

in addition to all that, if your working on your bike at home and truck it up the hills your going to have to second guess carb jetting for altitude, if its a significant difference.... i think a four stroke would be more forgiving in this respect.


Thats true. Two strokes are more sensitive to humidity, temperature and altitude versus four strokes.

It's just something a two stroke owner has to consider and deal with. Doesn't hurt to keep jetting kits handy. I can swap out a needle, pilot or main jet in under 15 minutes and the manufacturer's shop manual has various charts to help you make an educated decision on jetting.