Power delivery of KX verses CR

[KXFARMBOY]

With the KX having a "square" bore and stroke,and the CR 500 having a much more "oversquare" bore does the KX feel a lot stronger than a CR at low rpm's? Also is peak power about the same? Naturally we're talking stock against stock, or piped verses piped.

[stewart]

two stoke theory i have read says  two strokes run best sqaure like same stroke as bore size i think the k 5 is right on

[apple]

I had an 89 CR500, and a buddy had an 87 CR500. I heard that they toned the motors down since the 80`s.
I know mine had a powerband like a 250 and if you weren`t on top of it while on the gas the bike would toss you if you didn`t pay serious attention. My buddy`s 87 was even sicker. That thing made my knuckles hurt from the pulling that thing did, talking about stretched knuckles. Plus those things had lots of headshake. The KX is tons better on the low end, plus top end seems pretty close to the 89 I had.

[gowen]

I've been looking for a mid 86-'87 CR500 for that very reason. I've ridden one and loved it.

[Mick]

The KX does make a hair more power right off the bottom and on top.  But having rebuilt both of mine now I was surprised how much lighter the CR's crank and flywheel are.  The old CR feels a good deal more nimble at any speed then does the KX.
And also the CR isn't as pipey as KX riders would like to believe.  True the KX is the king of broad power, but the CR is the only bike that can run beside it.

[stock500]

I swore that a 500 was just too wild after riding my friends CR500.  It seemed like the second you touched the throttle the ass end was fish tailing out of controll.  However I got sick of riding 4-strokes in the dunes and getting left behind so I got the KX500.  My bike is a 2004, and 100% stock.  The power is smooth as glass as long as you don't stab it.  I love my bike and get a kick out of riding it in the dunes!

[CR480R]

As far as low end goes on my 98 cr500 ( I owned for seven years) and on my buddy Justins 88 and his 01 when you have a paddle on the bike in the sand you have to burn the clutch and push with your feet untill the bike comes up on a plane or It will die....    It could be because the cr500 is a pipey non power valve haveing back flipping piece of s**t.

Sounds to me like something may have been wrong with your bike... The '90 CR500 I had was neither pipey nor a clutch burner with a brand new 10paddle hooker... I havent had the chance to own or ride a KX500 yet, but I do know a properly tuned CR500 is far from being a POS... My only gripe was the headshake at speed, I could see one easily getting away from a smaller rider...

[KXcam22]

My 87 CR500 was very pipey.  It was the only open class bike I ever owned that wouldn't do long controlled wheelies on a gravel road.  Either no wheelie or wheely over backwards.  I had to put a steahly on just to ride it.   In comparison, I put a friend on my K5 who has just started riding, normally an insane thing to do. KX is such a pussycat that he had no trouble riding it without dying. I must admit though, that my 1982 CR480 had about the best powerband going strictly for MX.  Cam.

[Mick]

Anyone that has a remote grasp on what a power valve is and how it works knows It's impossible to have good bottom end and good top end on a two stroke engine without one.

I agree. I wouldn't argue the CR doesn't come on sudden and can't scream like a banshee.  Your explanation of how a KX pulls your arms is also taken right out of my mouth.  I suppose I can't use my current CR for this discussion, but I'll try anyway.  I have a PC exhaust and 39mm carb and it pulls smooth off the bottom and runs similar to a KX on top.  It doesn't match a KX at any point but maybe the midrange...but it's "close".  In sand drags I have matched my '89 KX 50/50 every time.  The KX also has extensive motor work.  In my experience it's the CR's ability to rev quicker that benefits it the most against a KX.

Overall I'm impressed how linear and strong my CR is for not having a power valve.  And I still havn't had any motor work done yet.
I have never ridden a CR I thought was gutless or needed clutch abuse to get moving.  If that's been your experience I have to beleive the Honda's you rode were clapped out.

[don46]

The Honda has a shorter stroke, smaller flywheel, and smaller crank webs, all this equals lighter quicker revving. So, In my opinion the Honda will rev quicker, but doesn't have the Torque of the heavier flywheeled, longer stroke K5 and thats power valve aside. I don't think the CR has any more top end than a KX, IMO on a stock bike it gets ther quicker. I have a modified 250 ignition that I would guarantee you will rev quicker than the Honda, I've had it on twice, now I'm trying to figure out how to tame it a bit right off the bottom, it way to viscious, way more so than the PVL. I'm thinking a programable ignition that I can retard the timing a bit right off the bottom, then advance it through the mid and retard again on top for the over rev.

Honda makes a good bike, they just aren't for me. This is one of things that will never be agreed upon, Honda riders will swear by it and kawi riders will swear at it.

[Mick]

This is what Dirt Rider had to say about the '92 CR500.  (Nov 91, pg. 35)

"No one ever accused the CR500R of having a meek motor, but the new version is very easy to control.  Now it's even smoother than the KX500."

They didn't say "about" or "nearly as smooth".  They said "SMOOTHER" than the KX.  And the CR got wider gears in the year to follow.
All I'm saying is the 500 motors havn't changed much since '92.  And a properly running CR isn't pipey or hard to ride. I have to say something because my primary ride is a CR500AF.  And it's no slouch in the power department, in fact it doesn't give up much to my ported '89 KX500.

I like both motors.  If my KX motor was dressed in aluminum I might ride it more *shrug*  But as it sits the KX has a paddle tire that hasn't come off in 4-5 years.  But the CR gets ridden weekly on track and trail.

[gowen]

The Honda has a shorter stroke, smaller flywheel, and smaller crank webs, all this equals lighter quicker revving. So, In my opinion the Honda will rev quicker, but doesn't have the Torque of the heavier flywheeled, longer stroke K5 and thats power valve aside. I don't think the CR has any more top end than a KX, IMO on a stock bike it gets ther quicker. I have a modified 250 ignition that I would guarantee you will rev quicker than the Honda, I've had it on twice, now I'm trying to figure out how to tame it a bit right off the bottom, it way to viscious, way more so than the PVL. I'm thinking a programable ignition that I can retard the timing a bit right off the bottom, then advance it through the mid and retard again on top for the over rev.

Honda makes a good bike, they just aren't for me. This is one of things that will never be agreed upon, Honda riders will swear by it and kawi riders will swear at it.

Do share? I don't see how you can get quicker than a PVL, when the flywheel basicly weighs less than my old '98 kx125s flywheel..

[CR480R]

This Is a good example of what Im talking about this is a cr500 under heavy load listen to the engine and how it labors when Its not on the pipe. watch the vid a couple of times and pay attention to how the engine goes on and off the pipe and  how abruptly the power comes on. Now imagine ridding that bike with a stock wheel base on steep mountain trails with rocks and shale Like where I live and you may understand why I do not miss that bike.
   
                              http://www.youtube.com/watch?v=NHmBMSMXbUM

This video is a horrible example... Just because the guy fanned the clutch and got bucked off doesnt mean the bike is too pipey... I have seen many hillclimb vids of KX riders getting tossed like that too... To me it looks like the guy was either in the wrong gear or had too much tire... not to mention his riding sucks... And its hard telling what has been done to the bike...

What Dirt rider failed to mention was they detuned the cr500 because a lot of people got hurt on the earlier bikes and people were scared to ride or buy it and sales of the bike were dismal to the point they almost quit procucing the bike. Magazines will seldom strait up bash a manufacturers bike do to the fact companies like honda give them a lot of money to push their products. Smooth power delivery is a nice way of saying they took a bunch of compession out of the bike to soften the hit but that was a trade off that made the bike hard to start but I'm sure yours starts first kick every time though right.

From my experience the "Detuned" bikes start even better than the older ones... a stock '01 CR is a proven one kick wonder... My '90 had the compression bumped(190psi vs. 150psi) and it still didnt have any kind of rider ejecting "hit"... I dont doubt that the KX has a nicer powerband, but I think you are foolish to assume all CR's have the same problems yours did...

[Mick]

BDI I'm not arguing that the KX doesn't run stronger.  I'm just saying you obviously had a bad experience that anybody else would be hard pressed to share.  Your CR sounds like it needed a fresh piston...

Roger Decoster on the '95 CR500R (Dirt Bike '95 pg. 60)
"Right up front, I have to say this is my favorite motor...you can put it in a tall gear and let the revs drop to a point you can hear each power pulse...CR has gotten mellow over the years...on top the revs are choked off by chicanes in the silencer...most appealing aspect of the Honda motor is how civil it is...Honda was able to make the power delivery smooth without using excessive flywheel weight, which makes the bike feel surprisingly nimble."

Decoster on the KX, "comes on more aggressively than the Honda at first...in stock form, the KX should be able to outpull the CR on top...clumsy feel and slow throttle response...jetting the Kawasaki is a little rough...engine runs raspy off the bottom...shifting and clutch pull are good on the KX, but not as smooth as the Honda's."

I'm not biased towards one bike or the other.  I own and ride both.  But everybody should know the CR has got a darn good motor.

And yes my CR starts one kick    Doesn't your KX?

[don46]

The Honda has a shorter stroke, smaller flywheel, and smaller crank webs, all this equals lighter quicker revving. So, In my opinion the Honda will rev quicker, but doesn't have the Torque of the heavier flywheeled, longer stroke K5 and thats power valve aside. I don't think the CR has any more top end than a KX, IMO on a stock bike it gets ther quicker. I have a modified 250 ignition that I would guarantee you will rev quicker than the Honda, I've had it on twice, now I'm trying to figure out how to tame it a bit right off the bottom, it way to viscious, way more so than the PVL. I'm thinking a programable ignition that I can retard the timing a bit right off the bottom, then advance it through the mid and retard again on top for the over rev.

Honda makes a good bike, they just aren't for me. This is one of things that will never be agreed upon, Honda riders will swear by it and kawi riders will swear at it.

Do share? I don't see how you can get quicker than a PVL, when the flywheel basicly weighs less than my old '98 kx125s flywheel..

The PVL rotor is lighter than the 250 flywheel, but the 250 ignition is way quicker than the PVL, the only thing that makes sense to me, the 250 is digital and changes based on rpm and throttle position ( I use the 250 carb) the PVL is analog. I use the PVL on a nitrous bike, the compression is closer to stock, when I tried it on a bike with High compression I couldn't get it started, don't think I could spin it fast enough to generate the juice needed. Any way this is a work in progress because its way to nasty in it's current state.

Since this is the KX forum maybe we should just ignore the KX vs. CR thing while everybody is still happy