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300exlunatic
07-15-2003, 04:28 PM
two stroke or four stroke what are the advantages and disadvatages

Chanman420q
07-15-2003, 04:38 PM
lets say we have a 2-stroke 400cc engine and a 4-stroke 400cc engine. the 4 stroke is going to have more tourge and more power..... but the 2 stroke is going to be faster revving and create a better top end.

so the advantage to 2-strokes is the speed. disadvantages are top ends dont last as long as 4 stroke top ends. and u gotta mix the gas.

4 stroke disadvantages are, that there harder to work on internally, a lot more moving parts. and wont create the top end that a 2 stroke would create.

2 strokes tend to foul plugs a lot easier too

wilkin250r
07-15-2003, 04:49 PM
Since 2 strokes produce power every revolution, while 4 strokes produce power every OTHER revolution, it takes almost two times the dispacement of a four-stroke to equal the power of a two-stroke (i.e. a 250r has slightly more peak power than a 400EX)

Without a cam, valves, timing chain, ect, a two-stroke engine is much lighter than a four-stroke engine. A 250r engine weighs much less than a 400EX engine.


With higher revs, two-strokes require much more maintenance. They also produce more smoke and polution.

RustyShakelferd
07-15-2003, 04:57 PM
So a 500cc 4-stroke is the same as a 250cc 2-stroke? If so why are there not more 500cc motors out there?

300exlunatic
07-15-2003, 05:05 PM
if thats true then my 300ex wouldnt beat a blaster but iv smoked evry blaster i have raced

wilkin250r
07-16-2003, 05:23 AM
Originally posted by RustyShakelferd
So a 500cc 4-stroke is the same as a 250cc 2-stroke? If so why are there not more 500cc motors out there?

It doesn't come down to a simple displacement issue, because there are other factors that affect power. Compression, ignition timing, vavle timing, ect...

I think the main reason there are not more 500cc is because of race regulations. If I'm not mistaken (and somebody feel free to correct me on this) the limit is in the pro 250cc class was 265cc two-stroke, or 426cc four-stroke. However, I think that was recently changed to 450cc four-stroke. If a 500cc is too big to race, then why stop there? Just bump it to 600plus, like the DS650 or the Raptor.

wilkin250r
07-16-2003, 05:25 AM
Originally posted by 300exlunatic
if thats true then my 300ex wouldnt beat a blaster but iv smoked evry blaster i have raced

There are more factors than displacement. The blaster is one step above a mini, it's not quite "high-performance"

However, put $500 into your 300EX, and $500 into the blaster, and that blaster will make you look ridiculous in any drag race.

NTPracing22
07-16-2003, 06:29 AM
yall bout summed that up:D

the displacement regulations (around here at least) is 80 over your stock bore. making a 250r a 265r, and 400ex a 440ex..so on and so forth

Narly R
07-16-2003, 07:02 AM
ALL true, but now theres a new hi-performance 4 stroke, the 450! And with a few little mods it put out around 50 hp, and thats about the sam e as my 350r!:ermm: It depends on the engine too i guess...


I love both, my r hasnt ever ran riht since i got it and im finally almost there, so I cant really say yet, but i think id be a much better rider on a 4-stroke, cause on the trch u can come into a corner a gear too high and still make it just fine. I love the power of both, bt shure get tired of jets, mix, and race gas. But they shure rip WHEN running right!

NTPracing22
07-16-2003, 11:07 AM
when they run is correct. but also consider that your on a 17-13 year old bike

300exlunatic
07-16-2003, 11:34 AM
iv raced a blaster with pipes filter reeds all that and i smoked stock a blaster will never make my 300 look bad

Narly R
07-16-2003, 11:50 AM
Originally posted by NTPracing22
when they run is correct. but also consider that your on a 17-13 year old bike

Ya but 90% of it is within anew old. A two-stroke and a four-stroke are 2 COMPLETEY differnt machines!:ermm: If you have a 4 and 2 stroke of the same amount of cc's the 2 stroke will always win, that is if its running right.

NTPracing22
07-16-2003, 01:29 PM
as much as i love 4strokes, i'll always be a 2stroke guy. the snap you get when you hit the throttle is great. and now with my powervalve, it pulls bottom end like a 4stroke (for the most part).

BigThumper33
07-16-2003, 03:39 PM
A CR250 and CRF450 make almost exact hp numbers. I think they are within 2-3 of eachother in the 46hp range. The cc factor with a 4 stroke taking twice as much cc's as a 2 stroke stands pretty firm in that comparision.. It is only a 50cc difference from a 450 to a 500 so, the simple mathmatical equation stands pretty firm. Also the cr/crf comparison is much better because both bikes come from the factory modding very similar for racing applications. Not like a blaster....

300exlunatic
07-16-2003, 04:35 PM
i still think four stroke are better not that i care to much but they dont really pollute as much nad sound better

sleestack68
07-16-2003, 07:12 PM
Correct me if I'm wrong but the CRF requires quite a bit of maintenance and frequent rebuilds to maintain that kind of power.

If that is the case, I would much rather tear down a 2 stroke than have to rebuild a 4 stroke topend.

skemp
07-16-2003, 08:13 PM
You guys all made some very good points, and basically took the words right out of my mouth. I will add that I love 2 strokes for the power. There is so much more bang for the buck existing in a 2 stroke than in a 4 stroke. The only thing that keeps me from owning one in a quad is the reliability factor. I have much better things to do than spend time and money on rebuilds, so I just put the extra dough into my 4 stroke to make it perform, and can just ride it without worrying about when it is going to need a rebuild.

07-17-2003, 05:48 AM
I dont see any real advantages of a 4 stroke ...
as a matter fact ...more moving parts means more costly rebuilds ...but its definitely up to each rider ..to decide

nacs400ex
07-17-2003, 06:01 AM
Trust me, rebuilding a 4-stroke isnt very fun, it cost BIG money, especially when you decide to make it MX ready. 250r is like half the price, because it has half the parts. Thats why I am prolly gunna be selling the ol'400 and getting an R.

07-17-2003, 06:03 AM
yupper ..& rebuilding 2 strokes can be alot of fun ...especially the results :D

sleestack68
07-17-2003, 06:13 AM
The last time I rebuilt my R I was eating dinner, I walked into the garage and decided to loosen the head bolts between bites. One thing led to another and 7 minutes later I had the piston in my hand.

When I rebuilt my wife's atc 125m, I basically had to take a day off from work.

CrazyEX
07-17-2003, 06:21 AM
Originally posted by 300exlunatic
if thats true then my 300ex wouldnt beat a blaster but iv smoked evry blaster i have raced


1 Reason why you one.......10% machine, 90% rider. You were probably a better rider than he was...........So don't talk $hit about BLasters, there good machines.

wilkin250r
07-17-2003, 06:32 AM
Originally posted by "2-R's Rider"
I dont see any real advantages of a 4 stroke ...
as a matter fact ...more moving parts means more costly rebuilds ...but its definitely up to each rider ..to decide


There are definitely advantages to a 4 stroke. With more low-end torque, you don't have to feather the clutch out of the corners. They are definitely more reliable and don't require quite as much maintenance. You can argue emmissions and environmental factors. Along those lines, let's face it, the two-stroke is disappearing. The future of sport ATV's is most assuredly 4-stroke.

07-17-2003, 06:35 AM
Originally posted by wilkin250r
There are definitely advantages to a 4 stroke. With more low-end torque, you don't have to feather the clutch out of the corners. They are definitely more reliable and don't require quite as much maintenance. You can argue emmissions and environmental factors. Along those lines, let's face it, the two-stroke is disappearing. The future of sport ATV's is most assuredly 4-stroke. ...yeah yeah ...I was thinking of the EPA BS also ...but my 2STROKE aint going no where ...except maybe to a bigger trailer :D:eek:

300exlunatic
07-17-2003, 09:35 AM
my 300 is a way better bike than a blaster more bottom and top end and better hadling plus its a HONDA:)

300exlunatic
07-17-2003, 09:35 AM
my 300 is a way better bike than a blaster more bottom and top end and better hadling plus its a HONDA:)

curtissparks400
07-17-2003, 11:05 AM
Originally posted by 300exlunatic
my 300 is a way better bike than a blaster more bottom and top end and better hadling plus its a HONDA:)

sorry to break it to u, but u can do all the work in the world to your 300 and it would never touch a slightly modded blaster. im all about honda too, but my buddy has alot of work done to his blaster and no 300ex would ever touch it :D

300exlunatic
07-17-2003, 05:18 PM
what mods does your buddys blaster have i bet anything that if i get a 330 kit itl be in the dust if not already

310Rduner
07-17-2003, 05:52 PM
people use the whole rebuild costing money way too much. in all honesty, i replace a piston probably every 6-7 months, riding it HARD every time, but i ride every weekend if not then at least every other.. for several long hours at a time..

The pistons honestly arent that much, i believe the cost for wiseco is like 99 for the kit, some places 75...

spending 100 bucks every like 6 months is almost inconsequential..you could save up a dollar a day maybe, and probably afford it without even trying..

have fun spending tons of cash when the 4 stroke top ends go out..:eek:

two strokes are the best for power, the 250R will out handle ANYTHING... you can set them up for mad top end or very strong low end.. if you like the feeling of just hitting the gas.. and kinda cruising evenly up to speed. stick with your 4 strokes. If you like to actualy feel that you are picking up mad speed and have that feeling never end.. be smart and get a 2 stroke.

Riding in the dunes you can experience the power alot easier.. go to Any hill almost.. park with your tires ON the hill and take off after popping the clutch and shifting to third.. all of this is easy to do on a two stroke.. when i do it, raptors will try and line up right next to me.. and guess what?? they DONT have the power to make it!! they almost always end up turning down halfway up the hill or getting stuck..

Tomorrow and saturday i wil see how well this new yamaha can start up the hills from a dead stop at the bottom.. i think he MIGHT be able to do it..;)

300exlunatic
07-17-2003, 06:44 PM
if you want to get stuck in the mud go with 2stroke ifyou want real low end go 4 stroke

BigThumper33
07-17-2003, 08:07 PM
There are obviously some advantages to 4 strokes, otherwise why would so many top pros be running 4 strokes?

I don't see where a 4 stroke top end rebuild costs so much more than a 2 stroke. If all your doing is a basic rebuild, then the only thing more on a 4 stroke you may want to do is some new valve seals and maybe a valve job. You guys act like all top end rebuilds are gernaded motors!

My father has an R and I have an ex. Granted when riding the R it does feel faster, with its light switch power band, however when actually put head to head, my ex will beat it everytime. Granted his motor doesn't have much work, but all I'm saying is a lot of 2 stroke riders feel a lot faster than what they actually are.

I myself perfer a smooth powerband that doesn't tire you would nearly as fast and is more predictable. Argue all you want, but obviously a lot of pro's think the same way :blah:

310Rduner
07-17-2003, 08:19 PM
Originally posted by BigThumper33
There are obviously some advantages to 4 strokes, otherwise why would so many top pros be running 4 strokes?

I don't see where a 4 stroke top end rebuild costs so much more than a 2 stroke. If all your doing is a basic rebuild, then the only thing more on a 4 stroke you may want to do is some new valve seals and maybe a valve job. You guys act like all top end rebuilds are gernaded motors!

My father has an R and I have an ex. Granted when riding the R it does feel faster, with its light switch power band, however when actually put head to head, my ex will beat it everytime. Granted his motor doesn't have much work, but all I'm saying is a lot of 2 stroke riders feel a lot faster than what they actually are.

I myself perfer a smooth powerband that doesn't tire you would nearly as fast and is more predictable. Argue all you want, but obviously a lot of pro's think the same way :blah:

funny.. i know Exactly how my bike is going to react. no guessing done here??:confused:

BigThumper33
07-17-2003, 08:39 PM
thats funny, I generally see more two strokes get out of shape in whoop and rythmn sections....but maybe its just all rider?...or maybe not.

With the smooth power delivery of a 4 stroke, I don't see how it can't be more predictable than a 2. I own and ride both, generally I find to actually be consistant and predictable on my 2 strokes (R and when I had a 125) it was basically wide open throttle on take offs. On my thumper I feel I have more control, but thats just me.

310Rduner
07-17-2003, 09:34 PM
Originally posted by BigThumper33
thats funny, I generally see more two strokes get out of shape in whoop and rythmn sections....but maybe its just all rider?...or maybe not.

With the smooth power delivery of a 4 stroke, I don't see how it can't be more predictable than a 2. I own and ride both, generally I find to actually be consistant and predictable on my 2 strokes (R and when I had a 125) it was basically wide open throttle on take offs. On my thumper I feel I have more control, but thats just me.

as long as you always keep room in your garage for the r and other 2 strokes.. you will be allowed to keep your 4 strokes.. ;)

long as its still the put put bike.. :macho

its all good tho.. just preference.. even the R will still always be the best regardless of any considerations for preference...

cant argue with facts..:muscle:

twisted threads
07-17-2003, 11:55 PM
well I think its all up to were your are riding. If im riding around on the trails I would rather have my Ex. Its a lot easyer to handle that my R on the trails. But in the dunes...2 strokes Rule!! I think they both have there advantages but all in all I would half to say I like my R the best even though my Ex RIPS!! the R is a rush to ride.

BigThumper33
07-18-2003, 07:41 PM
No doubt its about what you feel better on. R's will always be awesome machines. For what I do 4 strokes are where its at for me, if I lived in the sand, I would definately have a 2 stroke.

Unfortunately the tree huggers are trying to do some damage....

CrazyEX
07-19-2003, 12:25 PM
Originally posted by 300exlunatic
if you want to get stuck in the mud go with 2stroke ifyou want real low end go 4 stroke

4 stroke or 2 stroke has nothing to do with getting stuck in the Mud......Same with low end. Actually 2 strokes make it through easier because they have the higher revs.

jwisniew
07-19-2003, 01:37 PM
this article explains it all, http://www.deepscience.com/articles/engines.html

curtissparks400
07-19-2003, 07:05 PM
Originally posted by CrazyEX
4 stroke or 2 stroke has nothing to do with getting stuck in the Mud......Same with low end. Actually 2 strokes make it through easier because they have the higher revs.

thats bs, 2 strokes do get stuck easier cause they spin crazy, a 4 has low end torque and hooks up. the thumpers rule!!!!!! has anyone riden a yz250f or 450f. those bikes are amazing. once u ride them u will never go back do a ring dinger.

sleestack68
07-19-2003, 08:43 PM
I rode em, not impressed. I'll go back to my ring dinger.

BigThumper33
07-19-2003, 10:22 PM
Why do all the 2 stroke owners seem to think their quads rev to the moon? There are a lot of 4 stroke engines out that rev as high or higher than a 2 stroke.

I don't believe my 125 has a 13.5k redline like the yz250f.....;)

310Rduner
07-19-2003, 11:31 PM
Originally posted by jwisniew
this article explains it all, http://www.deepscience.com/articles/engines.html

that link was a Pos read.. i want my few mins back..:grr:

the whole part at the bottom from jonnes page.. really sounds like that guy knows his stuff:rolleyes: :rolleyes:

07-20-2003, 03:10 AM
when ya build a 4 stroke all you got is a heavier & more expensive POS :blah:

07-20-2003, 03:23 AM
why does everyone keep saying how fast 250r's are and how much power the 2 stokes have? :confused: I thought they were about 3 mph faster then an ex? I guess cuz you are trying to compare your power of a 300, 265, powervalved, piped R's to a stock 400ex.

BigThumper33
07-20-2003, 05:56 AM
Last night my little pos 4 stroke pulled on several 250rs, and I finished 4th in quad pro right behind a powervalved 265r...:huh must have been just coincidence right? :scary:

Bean
07-20-2003, 08:03 AM
did you ever think that maybe you are a better rider?



stock for stock, the R is a few MPH's faster than a 400, but any modding done, the R will be quite a bit faster, unless you get a full out motor'd 400 vs a piped stock R, then the R may lose, but equal modding, the R is faster

curtissparks400
07-20-2003, 09:01 AM
if you ever rode the yz250f dirtbikes or even the yz450f, those bikes are cleaning up every 2-smoke there is at the track. the engines are amazing. soon thats what everyone will be riding!!
the power is unbelievable:eek2:

BigThumper33
07-20-2003, 12:28 PM
Considering all us guys in quad pro have been racing together I have gotten to know them pretty well, and I can surely say I'm definately not better than most of them. We are all a fairly closely skilled group.

How much skill is involved for the holeshot? I know timing and such is important, but there isn't a whole lot of skill involved, and yet my "piece of junk" lightly modified 416 ex, pulls on R's, and I can say none of them had just a pipe! They ranged from stock with port work, to a actual cr250 cylinder, to a 310, to a powervalved 265.

While they are spinning, my "pos" is putting power to the ground...:blah:

310Rduner
07-20-2003, 04:31 PM
Originally posted by BigThumper33
Considering all us guys in quad pro have been racing together I have gotten to know them pretty well, and I can surely say I'm definately not better than most of them. We are all a fairly closely skilled group.

How much skill is involved for the holeshot? I know timing and such is important, but there isn't a whole lot of skill involved, and yet my "piece of junk" lightly modified 416 ex, pulls on R's, and I can say none of them had just a pipe! They ranged from stock with port work, to a actual cr250 cylinder, to a 310, to a powervalved 265.

While they are spinning, my "pos" is putting power to the ground...:blah:

i think part of what you said was fun to read and truthfull.. i deffinately think it was the last part :p

R-Crazy
07-20-2003, 04:33 PM
i have an R, love it, but the powerband is on or off, and it is a blast, but i would imagine a smooth powerband would be easier, but the rush just aint there, but o well, thats why there are powervalves:blah:

dave

Chef
07-20-2003, 05:01 PM
My 4 Stroke pulled on a ESR 330 PV. I know he wasnt spinning cause he runs a -3 swingarm and wheelies outta every corner...But there isnt a four stroke anywhere to stay in my R's dust. :D

BigThumper33
07-20-2003, 08:44 PM
What can I say, I try my best! :devil:

CrazyEX
07-22-2003, 06:27 AM
Originally posted by curtissparks400
if you ever rode the yz250f dirtbikes or even the yz450f, those bikes are cleaning up every 2-smoke there is at the track. the engines are amazing. soon thats what everyone will be riding!!
the power is unbelievable:eek2:


THat's on the track......10% Machine 90% Rider.......Top speed, there is no way a YZ250F or 450F will touch a CR or YZ250 2 stroke!

Fast250EX
07-22-2003, 07:32 AM
I am one of the few who likes both. I have never owned a 2-stroke but helped rebuild one and it is mighty easy. Really builds self confidence. I had an old Honda 250 utility 4 stroke ATV and after 17 years without nothing more than an oil change here and there, it still runs great. I sold it and the person that got it is still happy with it.

That is why I like four strokes, as well as the fact that nothing sounds better than a big bore thumper.

I have actually thought of getting a 250R or something at one time but I don't think I would do that as my main machine. It is nice to have a nice reliable 4 stroke to ride on and with all this high tech BS today to get the last bit of horsepower out of 4 strokes, 2 strokes are becoming obsolete little by little.

If lived by the dunes, I would have an R in a heartbeat but with all the trails out here, I need a thumper.

However, it will be a sad day when the MX and XC Pro classes are full of 4-strokes.:p

nacs400ex
07-22-2003, 02:57 PM
lol crf450's arent that reliable. You have to rebuild it faster than your average 4-stroke. Also money ends up cheaper with a 2-stroke- not as many parts, easier to fix stuff, cheaper to mod. I have priced it all out, and thats why I am getting an R.:D

hondafox440
07-22-2003, 03:21 PM
Listen to wilkin, he knows what he is talking about.

Engine tech is very complicated if you really want to get into it. 2 strokes rely on back pressure and vaccum effects to inhale and discharge the fuel/air mixture into the cylinder. In effect, the pipe (named expansion chamber for obvious reasons) acts like a supercharger, and at the point where it is working most efficiently (powerband), the volume of exhaust exiting the cylinder expands enough to create enough back pressure to force all unburned fuel back into the cylinder before the exhaust port closes. If the engine is revving too slow, not enough backpressure is created. Too fast, and the exhuast port is closed before the mixture returns. That is why changing the pipe, thus changing the point of reflection (where backpressure is initiated) can change where in the RPM range the powerband is. Powevalves work in conjunction with the pipe to keep the exhuast ports open enough to allow any escaped mixture back in, but prevents the large amounts of unburned fuel from entereing the pipe at low RPMs like a non PV engine does.

4 strokes have cams and ports, which is a whole nother theory all in itself. The idea of intake ports is to get the maximum amount of port area, to allow the most fuel/air possible into the cylinder. The more fuel you allow to enter, the more the engine can breathe and the more top end power it makes. So why dont engine builders just have one huge intake and one huge exhuast port? The problem is, you need to make the actual size of the port small. This, due to the venturi effect (thanks Archemedes) causes the fuel to enter at a high velocity. The faster the fuel enters, the better bottom end the engine has. Here's where multiple intake ports come into play. By making 2 medium size intake ports, you get the best of both worlds. More top end, yet you dont sacrifice low end. This idea is the basis of Yamaha's 5 valve design. By incorporating 3 intake ports, port size can be reduced further, but overall port area remains the same, thus more low end. Though in theory it works, only Audi and Yamaha can find beneficial effects to the 3rd intake ports.

Then comes the cam train. Many engines are SOHC, so its a single cam going down the middle of the head, with rocker arms activated by the lobes on the cam. The rocker arms activae the valves. Advantages to this design is it is simple, and works well. It's lighter than a DOHC engine also. The DOHC principal invoves running one cam over each the intake ports and the exhuast ports. In this design, valves are actuated by the lobe on the cam istelf, thus eliminating rocker arms. This means less reciprocating and revolving mass, which allows the engine to rev higher. Thats why your YZF redlines around 14K, and your CRF around 11K.

I could go on and on, but I've bored you enough. :D

jwisniew
07-22-2003, 04:13 PM
nice post

MojaveKing
07-22-2003, 04:59 PM
thanks for the great info guys

hondafox440
07-22-2003, 07:31 PM
Yea, np..

Just bumping this because I didn't type all that for 2 views, lol.. :D

twisted threads
07-22-2003, 11:45 PM
Originally posted by hondafox440
Yea, np..

Just bumping this because I didn't type all that for 2 views, lol.. :D

lol I don't blame you! Great INFO.:cool:

wilkin250r
07-23-2003, 05:56 AM
Excellent info hondafox440. I'll just add a little to your explanation of two-stroke pipes.

Just as he said, two-strokes rely on pressure and vacuum effects to inhale and discharge the fuel/air mixture. I highly recommend looking at Two Stroke Motor Explanation (http://www.exriders.com/techarticles/twostroke.html) in the tech section.

When the exhaust port opens, the rush of exhaust creates a positive-pressure pulse. Several of such pulses creates a sound wave at exactly the same frequency as the engine RPM. It is this sound wave vibrating through the expansion chamber that creates this pressure and vacuum effect to allow the engine to run at optimum efficiency.

The first section that comes out of the cylinder is called the headpipe. Early pipes were simply a straight pipe. It was found that the sound wave generated at the resonant frequency of the pipe would create a negative pressure wave that would pull exhaust gasses out of the cylinder. However, there is only one resonant frequency of a straight pipe, which results in a very narrow powerband.

By adding a divergence section, like a megaphone, to the end of a straight pipe, the returning negative pressure wave can be changed based on the rate of divergence. A small taper gives a longer wave, while a sharp taper acts more like a straight pipe. The returning negative pressure wave is not as strong, but it is longer, effectively broadening the powerband. It is also strong enough to pull in a fresh fuel/air mixture. Unfortunately, it can also pull the fresh fuel/air mixture OUT of the cylinder before the exhaust port closes.

By adding another, reversed megaphone, you can you can reflect back some of the positive pressure. This is obviously the big bulb in the middle of the pipe. Where it starts to bulge out is the first megaphone that alters the negative pressure wave, and where is starts to constrict is the reverse megaphone that reflects the positive pressure wave. If timed properly, the negative pressure will pull the exhaust out, and just as it begins to pull the fresh fuel/air mixture out as well, the returning positive pressure wave will force it back into the cylinder. This is why you get an amazing increase in power at a certain RPM, all these factors come together to create the powerband. By altering the lengths and divergence rates of the different sections, you can alter the powerband.

Too technical?

hondafox440
07-23-2003, 01:41 PM
I always thought the exhaust (pressure) wave was not a sound wave, but just a pressure wave moving at the speed of sound..

400extracc
07-23-2003, 02:09 PM
reading bout the 300ex and blaster, i just have to give my two cents. i have 400ex and i love it. its is perfect for the type for riding i do.
my bro went out and got himself a blaster. man can this little thing go!!! its got a few mods, and it will kick any 300ex's *****.
man, its like one second, your not moving, then the other your trying to hold on.

the ony think i would change is a better set of shocks.

other than that, i thinks it smokes....

thasts' just me!!!!

Fast250EX
07-23-2003, 03:44 PM
Yeah, I always razz on the little 2 stroke machine but with certain mods, you can make a blaster kick some serious tail, with a very small amount of dough. I've heard of 240 kits beating 400EX's easily.;)

ESR250R
07-23-2003, 06:13 PM
Originally posted by BigThumper33
Considering all us guys in quad pro have been racing together I have gotten to know them pretty well, and I can surely say I'm definately not better than most of them. We are all a fairly closely skilled group.

How much skill is involved for the holeshot? I know timing and such is important, but there isn't a whole lot of skill involved, and yet my "piece of junk" lightly modified 416 ex, pulls on R's, and I can say none of them had just a pipe! They ranged from stock with port work, to a actual cr250 cylinder, to a 310, to a powervalved 265.

While they are spinning, my "pos" is putting power to the ground...:blah:



there is actually alot of skill involved in holeshoting. tire choice, gear choice (2nd for me), shifting style, weight distributing (alot more work when i got a shorter swingarm), clutch work on take off, reaction time, etc. one of my buddies just got a 250r and on that last holeshot him and i were even to 5th gear beating a cannondale moto w/ hmf pipe and a yzf426 quad. i have a 260 cc ported lrd top end with a 38mm carb and a esr pipe. so skill level has alot to do with holeshoting. i have yet to see a 416 beat me on a holeshot and the only 400ex that comes close is a is a ct racing 440ex, and i can still beat him if i get off the line decently. i am the only person in the top 10 in my district point that races a 250r and now all in two weeks i've seen 4 other people switch to the 250r. two coming from cannondale motos, one coming from a 416 ex, and one coming from a worked cannondale canniable.

wilkin250r
07-23-2003, 06:30 PM
Originally posted by hondafox440
I always thought the exhaust (pressure) wave was not a sound wave, but just a pressure wave moving at the speed of sound..

I guess it depends on how you want to look at it. Technically, it is just a pressure wave, but then again, a sound wave is just a sequence of pressure waves.

Six of one and a half dozen of the other...:ermm:

rooster300ex
09-12-2006, 09:25 AM
Originally posted by R-Crazy
i have an R, love it, but the powerband is on or off, and it is a blast, but i would imagine a smooth powerband would be easier, but the rush just aint there, but o well, thats why there are powervalves:blah:

dave


Thats what I like about them.

bwamos
09-12-2006, 10:13 AM
Originally posted by wilkin250r
I guess it depends on how you want to look at it. Technically, it is just a pressure wave, but then again, a sound wave is just a sequence of pressure waves.

Six of one and a half dozen of the other...:ermm:
What he said.

Pressure differentiations is what creates the "wave" in a sound wave. That's why you're ear drum moves, things will vibrate when a deep base note is hit on the radio, and why sound will not travel in space. ;)

Amplitude is the amount of pressure.
Frequency is the rate of high/low pressure changes.
The more pressure changes per second the higher the note.. the less the lower. Increased pressure makes it louder.

krt400ex
09-12-2006, 11:02 AM
Originally posted by Chanman420q
lets say we have a 2-stroke 400cc engine and a 4-stroke 400cc engine. the 4 stroke is going to have more tourge and more power..... but the 2 stroke is going to be faster revving and create a better top end.

so the advantage to 2-strokes is the speed. disadvantages are top ends dont last as long as 4 stroke top ends. and u gotta mix the gas.

4 stroke disadvantages are, that there harder to work on internally, a lot more moving parts. and wont create the top end that a 2 stroke would create.

2 strokes tend to foul plugs a lot easier too


the 2-strokes have 2x the power per cc. they have a power stroke on every upstroke. a 400cc 2-stroke is going to be alot more powerful than a 400cc 4-stroke. the 4 banger may feel faster but that is only because thay produce more torque. there is no competition. a 2stroke is more powerful. however, they r not always better for ur application. thay r lighter, and teand to handle batter in the air because of their light weight, but 4strokes r better for most all applications because u have more options as to how u want to ride for certain applications.

F-16Guy
09-12-2006, 12:19 PM
Originally posted by BigThumper33
...There are obviously some advantages to 4 strokes, otherwise why would so many top pros be running 4 strokes?...

The Pro Production rule keeps them from riding 250R's, so they really don't have a choice. If you're Honda or Yamaha and you want to promote your new 4-stroke quad, how do you do it? You force the pro riders to race them by changine the rules. The 250R is still extremely hard to beat on the track, especially with a power valve cylinder.

krt400ex
09-12-2006, 12:32 PM
Originally posted by F-16Guy
The Pro Production rule keeps them from riding 250R's, so they really don't have a choice. If you're Honda or Yamaha and you want to promote your new 4-stroke quad, how do you do it? You force the pro riders to race them by changine the rules. The 250R is still extremely hard to beat on the track, especially with a power valve cylinder.


x2, i would like to see what it is like with 2 and 4 strokes on the track in the hands of the pros. it might be pretty neat to see

Xater
09-12-2006, 07:01 PM
theres nothing like the sound of a 2 stroke.... as for for 300ex guys rambling about how they own blasters, my freind has a 300ex and he doesnt touch me i usually have to wait up for him :p and 2 stroke are alot easyer to mod!! throw a pipe on and your going twice as fast and hitting high rpms when you touch the throttle :blah:

ThrowinRoost89
09-13-2006, 10:02 AM
2 strokes are the best and easiest/cheapest to mod. it takes alot more money to get 75-80hp out of a 4 stroke than it will be to get out of a banshee or a zilla.

calds650
09-13-2006, 11:56 AM
I love the sound of a 2 stroke but sad to say they are history thanks too the EPA :(

7 speed
09-13-2006, 12:15 PM
2 stroke= Sand
4 stroke = everything else

Lets keep it simple;)

Toadz400
09-13-2006, 05:57 PM
Originally posted by 7 speed
2 stroke= Sand
4 stroke = everything else

Lets keep it simple;)

2 stroke = Everything
4 stroke = For Pansies:blah:

Why did someone bring up a 3 year old thread?:D

†2005 400ex†
09-13-2006, 07:43 PM
I personally love anything involving internal combustion, be it two or four stroke, and maybe a deisel added in there :D

krt400ex
09-14-2006, 11:57 AM
Originally posted by Toadz400


Why did someone bring up a 3 year old thread?:D


i don't know why someone did that.


four stroke/ two stroke= anything. make it ur choice. ;)