Older bikes as fast as the new bikes ?

john3_16

Member
May 17, 2004
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I've read some posts on here about the older bikes making just as much power as the new ones and it got me curious if that was true or not.... I got out some old MX magazines from the late 80's and looked at some of the dyno charts of a few bikes to see how they compare with the newer ones...

I was surprised at the difference...In MX bike terms the differences are huge..

The 1988 YZ250 made 36.2 hp.

1987 KX250 made 38.9 hp.

1987 CR250 made around 35 hp.

1987 CR125 made 25.2 hp.....125's now are making close to 34 hp (KTM).

250's are making around 46 hp or so...About a 10 hp difference which doesn't sound like much but that's a huge difference on a small bore 2 stroke..Not to mention the bikes today are about 12 lbs lighter...Some 125's are making close to what the 250's made back in the 80's....However, you have to admit that the torque of the 250 makes a big difference evem though peak hp numbers are close...
 

sodflyer

Member
Jun 30, 2004
186
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Well, I can't say that I am any faster when I was riding my 88yz250 about 12 years ago than I am with my 04 yz250..... but I do notice that it does not take much to get the front wheel off of the ground to where I don't remember being able to do that on the 88 even after a fresh top end. Yesterday I thought I was fixing to eat some dirt coming out of a uphill turn off to the left... gave it a little more gas and rode my highest and longest wheelie yet through the turn... but I was sporting a pretty big grin :) it's all fun. Jeff.
 

va_yzrider

Member
Apr 28, 2003
353
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I don't necessarily attribute the hp rating to the term "faster." Even if the hp was exactly the same from the 80's to the current bikes, the much improved suspension and reduced weight of the new bikes will make them "faster." Or maybe it just makes us faster. Either way, IMHO, the new bikes are faster overall.
 

john3_16

Member
May 17, 2004
808
0
Shocknut said:
Find something on the 85 YZ 250 if you can. I recall reading that it busted out like 40-42hp and I think that came from a Dirt Bike Magazine test article.


That's impressive for an old bike....I remember reading about the 86' YZ250 and the 85' model was mentioned in the same test article as being more powerful than the 86'.....However, they didn't give the hp figures....
 

Casper250

Motosapien
Dec 12, 2000
579
1
There's a guy in my racing district that looks like he came from a time warp from the late 80's. His bike, his gear, his truck are all from the late 80's and he has to be in his late 30's early 40's. This guy flat out flys on the track. He came in 3rd in the 250 expert class and was in a bike length or two of second place. The first and second place guys were riding 450's and he was riding an old CR250.

His bike looked stock. Stock seat cover, stock pipe, rear drum brake, and neon blue grips. So I would say that older bikes will always be as competative as rider who rides it.
 

MXP1MP

Member
Nov 14, 2000
1,845
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it only made like 38 max in 85, it just was considered "fast" cause it had a really strong mid range hit. The 86 was actually better :) it had a better broader smoother power band us non pro's apperciated more plus better suspenion and ergo's! You sure that hp figure is right on the '87 CR 250 I thought it was more like 38.5ish that bike was very fast but it's hard to ride a 250 all out it was all mid/top the 86 was easier to ride I liked it's broader motor more. I also really liked the 88 RM 250 (bob hannah model if ya ask me) that was an awesome bike is terms is suspenion motor was average then. I liked the 89 YZ 250 vs the 88 musta been those USD forks (they was trick then) Damn i've ridden alot of bikes. hmmm maybe it's time for a 250 again.
 

Jeff Howe

Member
Apr 19, 2000
456
1
I had the 85 and 87 YZ 250's in my garage at the same time so I was able to directly compare. Owning both bikes made that easy, and the 87 was for all practical purposes the same as the 86 motor....mid/top. The 85 was low/mid and had healthy grunt. I much preferred the 85 motor, but after I had the 87 done up by Pro Circuit and got used ot it that one was much faster.

No contest...85 had the best motor and 87 had the best chassis. I should have stuck the 85 motor in the 87 chassis instead of spending money on the 87 motor.
 

john3_16

Member
May 17, 2004
808
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MXP1MP said:
it only made like 38 max in 85, it just was considered "fast" cause it had a really strong mid range hit. The 86 was actually better :) it had a better broader smoother power band us non pro's apperciated more plus better suspenion and ergo's! You sure that hp figure is right on the '87 CR 250 I thought it was more like 38.5ish that bike was very fast but it's hard to ride a 250 all out it was all mid/top the 86 was easier to ride I liked it's broader motor more. I also really liked the 88 RM 250 (bob hannah model if ya ask me) that was an awesome bike is terms is suspenion motor was average then. I liked the 89 YZ 250 vs the 88 musta been those USD forks (they was trick then) Damn i've ridden alot of bikes. hmmm maybe it's time for a 250 again.

Well, if it only made 38 in 85' then that's 2 hp more than the 88' YZ250...


I'm pretty sure that the number for the 87 is correct because in the test for the 87' KX250 they said that the KX made about 3 HP more than the CR they tested...So with the KX making 38 that would put the CR about 35....
 

john3_16

Member
May 17, 2004
808
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Casper250 said:
There's a guy in my racing district that looks like he came from a time warp from the late 80's. His bike, his gear, his truck are all from the late 80's and he has to be in his late 30's early 40's. This guy flat out flys on the track. He came in 3rd in the 250 expert class and was in a bike length or two of second place. The first and second place guys were riding 450's and he was riding an old CR250.

His bike looked stock. Stock seat cover, stock pipe, rear drum brake, and neon blue grips. So I would say that older bikes will always be as competative as rider who rides it.


That's cool to see...If that guy could do that well on an old bike I'm sure he would've done even better on a new one..But it just goes to show that in the right hands these older bikes can still be competitive :yeehaw:
 

kx134

Member
May 4, 2004
58
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my old 86 kx 250 was 100 percent as fast as my buddy's 02 cr 250 with some engine work...as long as we didn't turn or anything lol
 

pace

Member
Nov 21, 2003
479
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I need one of those 42HP 125s! You realize that some 250s are struggling to break 45HP... :ride:

Most 125s in fact dyno in the low 30s. Maybe mid 30s if it's made in Austria. ;)

-Pace
 

2smoke

Member
Sep 21, 2001
570
0
Thats the key. Japs measure at the crank. Euro's generally measure at the gearbox with a roughly 7% loss between the two readings. But 42 HP would definietly be at the crank.....not the rear wheel.
 

JasonWho

Member
Apr 10, 2002
2,109
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Casper, thanks for the pic! It looks like an '87 to me. It has a rear disc. I think the '86 had drum brakes, but I don't know for sure.

jon316- why do you say he has an 80's style? I am purely trying to learn here, not making any jokes at all. Thanks.
 

Rider 007

Member
Feb 10, 2000
224
0
JasonWho said:
Casper, thanks for the pic! It looks like an '87 to me. It has a rear disc. I think the '86 had drum brakes, but I don't know for sure.

Yes, that's an 87.

You are correct in that the 86 had a rear drum. The 88 was blood red and had the first "low boy" pipe.

:ride:
 

john3_16

Member
May 17, 2004
808
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jon316- why do you say he has an 80's style? I am purely trying to learn here, not making any jokes at all. Thanks


If you ever have a chance to look at some old magazines you'll see some similarities...Ususally handling of the bike will affect the riding style(unless a guy is what they call a squid and he's riding new bike and he's hanging off the bike like they did in the 70's)...Over time, bikes have gotten better and riding styles have changed to make the most of the way the bike handles.....Today that faster riders tend to appear more neutral and arched on the bike...By contrast in the 70's you would see the top riders using the rear of the bike more and they would be hanging off the back...This is because that style worked best on those bikes...
 

blackoutyz125

Member
Aug 7, 2004
45
0
I had my 89 yz125 dynoed just after i rebuilt the motor, it made about 29 hp. The bike is pretty much stock except for procurcuit pipe and silencer. I was fairly impressed, but when riding the newer bike i can definatly feel the extra power they have.
 
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