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old dirtbikes power vs new

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I got a 1991 kx250 i just rebuilt, rode it for the first time and it blew my mind, it is rediculously fast, I have a 1994 kx500 and a 1986 kx500 and a 2003 xr650r with the hrc kit and this kx250 honestly has more power it feels like, its mid and top end is so pyshco its unreal, my buddies 2001 yz250 feels like a baby bike in comparison it has 0 top rpm power, are the new bikes really faster? I Had a 1989 rm250 and it had psycho power to it rivalved the kx500s In my experience it seems like the late 80s early 90s 250s are alot faster than the new ones? has anyone else noticed this? it seems like the new 250s only pull at extremely low rpms and have no top rpm power and the old 250s are the exact opposite

maybe my buddies with the new 250s are all out of tune or something idk thats why im asking

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two strokes havent really changed all that much. The big difference between a new bike and an older bike is the feel of the bike. Any bike with a lot of hours on it feels really "loose" to me, where as new ones feel really tight and are really predictable...

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I haven't rode too many newer smokers, but my 05 is pretty fricking harsh when it comes to power. My 98 was fast, but smoother. Didn't rip my arms off. Like DMM said and IMO, cockpit feel is the big difference. You can tighten up an old bike by replacing all the steering and suspension bearings, seat foam (biggie), and repair or replace control pivots (levers, pedals, kicker). Nothing like a rattling old kick lever about to fall off any sec.

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It may "feel" faster compared to newer two strokes only because the power isn't smooth and you're not putting it

to the ground.

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My old 91 ran great and I felt it ran better than my 99 when I got it, 99 runs better now though :thumbsup: . I had afew people ask me if I had put t KX 500 in my 91 cuz it was fast.

Ed

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the main diffrence compared to a vintage bike.... im talking like the 70s, and a newer bike 85 and up is the new bikes have power valves... they make a huge diffrence . i have a 79 rm 125 and a 95 kx 250 . the rm dose not have a power valve .... huge diffrnce in were you [have power

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My 1990 Kx 250 Is an amazing bike in the bush, I love it, Seems to have heaps of low down power (for a smoker) and goes off like a hand grenade when you want it to lol! I have just as much fun on it as all my mates with there 13000 dollar 4 strokes

:thumbsup:

Hang on... I have more fun !

Edited by KX25O

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Going back further, I used to ride RM400's (79,80) and they put out about 36-38 HP - I still ride the same trails today and my good running KDX200 actually pulls some of the uphill trails better...it puts out about the same HP but with power valves has a longer flatter torque curve (and one more gear). The RM400's would tend to have to big a gap between the upper gears for some situations - if you couldn't keep it on the pipe you lose. After power valves were pretty much figured out by the manufacturers, I haven't seen much difference in 250 power other than that smoothing-out effect to get more torque over a longer rpm range. One of my favorite bikes, power-wise, was an 89 KX250 I had. Big mid-range with good off-bottom. I had no problems keeping up with anyone while I was still racing it in 2002. The 96 WR250 I have (YZ engine with wide ratio box) feels a lot like that old 89 KX.

Edited by SPUTTER
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Its probably because suspension has came a long way since then. 20mph on an old bike feels like 50mph a newer bike.

You are probablly right that your buddies are out of tune or need top ends. Newer motors produce better more usable hp compared to the old on off switch type 2t's.

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