horsepower of a 250 back in the late 80s?

oldfrt613

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Nope, more like 41-42 hp and no where near the broad power band of today.
 

Rider 007

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Feb 10, 2000
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I remember when the 84 CR250 hit 40 HP. It was hailed as a rocket.

It was also a bit of a grenade.

The biggest improvement has been the breadth of the power... there is much more area under the curve.

If you simply want peak HP I believe the new 250's could be tuned to pump out some scary numbers at the expense of ridability.

:ride:
 

Rider 007

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Maybe a Husky 250. :nener:

I think I heard the 06 KTM 125SX was hitting like 37 off the floor.

That's a big peak number for tiddler.

:ride:
 

CaptainObvious

Formally known as RV6Junkie
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A friend of mine has an '89 YZ250 that he still rides (it's in perfect condition - better than new). The engine has been bored, ported and is always in a proper state of tune. And I hate riding the darn thing!

Not only is the throttle sensitive, but the power comes on suddenly, all within a very narrow power band. It's like riding a bike with a switch for a throttle. Without fail, every time I ride that bike I hand it back to it's owner with one of my body parts hurting or bleeding (or with real bad poison ivy - but that's a ugly story).

Anyway, the owner of this rocket powered sled is always eager to point-out that his 16 year old bike makes just as much horsepower as a new bike, which I'm sure it does. But do not confuse quantity with quality. His YZ is evil and a real handful to ride, unlike a modern bike.
 

oldfrt613

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I thought that sort of thing is why we like 2-strokes ! :laugh:
 

DLHamblin

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May 27, 2005
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Nevada Sixx said:
HI, anyone remember what the HP of a 250 was back around 1988? Was it pushing 45+ like they do today?

thanks.

Well, the 87 YZ-250 I had dyno'ed at 38 which was typical for that period as I recall (I know many mags listed around 40 for 250's then but that must either have been at the crank or advertising hype; I don't recall any stock ones getting 40 or more at the rear wheel on a dyno but I could be wrong...). Don't know what my '89 had.
 

DLHamblin

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May 27, 2005
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CaptainObvious said:
A friend of mine has an '89 YZ250 that he still rides (it's in perfect condition - better than new). The engine has been bored, ported and is always in a proper state of tune. And I hate riding the darn thing!

Not only is the throttle sensitive, but the power comes on suddenly, all within a very narrow power band. It's like riding a bike with a switch for a throttle. Without fail, every time I ride that bike I hand it back to it's owner with one of my body parts hurting or bleeding (or with real bad poison ivy - but that's a ugly story).

Anyway, the owner of this rocket powered sled is always eager to point-out that his 16 year old bike makes just as much horsepower as a new bike, which I'm sure it does. But do not confuse quantity with quality. His YZ is evil and a real handful to ride, unlike a modern bike.

Since I haven't had it since '91 its just my memory; but I don't recall my '89 having near the pull of my '06 YZ-250; and definitely not the width (or "quality") of power spread the '06 has. The '06 pulls from lower much better.
 

Micahdawg

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Feb 2, 2001
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The new 125's are "approaching" the same power level of the early 80's 250cc two strokes. 125's are cranking out 35+ HP now which is probably close to what early 80's machines were making (maybe they were closer to 40).

I had a 89 KX250 that was pretty mild. Stock bore, stroke, 185 psi compression on new rebuild and it ran within a few HP of my 97 RM250. I would guess the KX was under 40HP at the wheels while the RM was just over 40HP at the wheels.

Seems like new 250's can achieve around 43-45 HP at the wheels now with little effort.

The power valve systems started getting more complex throughout the 80's. Early 80's saw more of a simple butterfly in the exhaust port while my 89 KX had the KIPS with 3 ports...its a slick design and the bike ran great.

Micah
 

john3_16

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May 17, 2004
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I have some old mags with dyno charts and the 250's of the mid to late 80's were putting out HP numbers from 35 to 40....

We have 125's that show comparable numbers today but don't get confused by the numbers...The 250's are putting out more torque and are putting these numbers down at a lower rpm...The HP figure doesn't tell the whole story or how powerful a 125 of today would feel by comparison.
 

NO HAND

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I had a chance to try lately a completely restored 1985 cr250 and was surprised at how little power it had compared to recent bikes. Also, the way the geometry is made, it fell like it's not competitive traction wise with what we are used to now. The old bike fell like the little power it had wasn't effectively translated to forward motion. I'm positive, any recent 125 would be faster than this bike stock. It's still a very nice bike and it's fun to see it running today. I would enjoy it in a sand pit, but perhaps not so much on a mx track.
 
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SFO

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my '90 ktm 250 was based on the previous year cr 250.
It made 43 rwhp on a dynojet 150.
It was the ex-c version too.
It was a great woods ripper.
 

uts

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Jan 8, 2004
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Just remember,

Maximum HP output is very dependant on RPM.

For example my IT465 (2 stroke) probably only puts out the same overall HP as a newer 250, However, the 465 probably does it at about 3000 rpm less than the 250 - the bike wasn't made to rev. But it feels way more powerfull in the low revs

If you built a 465 2 stroke to rev out to 10 000 rpm it would waste a 250 in the HP department. It's all about RPM

The new 450 4 strokes wouldn't be so powerfull if they didn't rev to the moon.
 

uts

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4thGearAndPinned said:
Oh yeah? The easy-to-use torque band begs to differ.


I am not argueing with that, but I bet if you look at the max hp output it's at 9000+ rpm. If you compare that to an old say XL500 (old school 4 stroke) you will see the newer ones have much more hp but also put it out at higher rpm.

Obviously it's not just rpm that's involved - these new 450's are race engines. I'm just trying to make the point that max hp doesn't always tell the story of the feel of the power of a bike.
 

76GMC1500

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Oct 19, 2006
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The service manual for my friends 1988 KX 250 says it makes 51 hp. It says the 125 makes around 32 and the 500 is at 62 for the same year.
 

Steve St.Laurent

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My '89 cr250 feels every bit as powerful on top as my '04 cr250 - if not more. But like said above it hits like a light switch. The '04 is FAR easier to ride.
 

2strokerfun

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May 19, 2006
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I am always amazed at how the modern 4strokes hp drops so sharply after about 8k rpm when I look at the dyno charts. I'm not sure the numbers always tell the whole story, though.
I went to an indoor race recently and it seemed like the 450 guys only had to blip their trottle about 5 times to go around an entire lap: "Blip"--jump a double; "blip"--jump another double; "blip" --jump another double; well, you get the picture
 
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2strokerfun

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May 19, 2006
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Nearly all the dyno charts I've seen show they peak at about 8K, give or take 500 or 1,000. Never has made sense to me, but I see it again and again. Kind of off topic of thread now, though.
 

76GMC1500

Uhhh...
Oct 19, 2006
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You must be getting the 2-strokes mixed up with the 4-strokes. The 2-strokes peak at 8000, the 4's peak at 9, but carry on to 11,000. The drop off is not sharp.
 
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