C series hp

Discussion specific to the various air-cooled KDX models sold in the USA
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dsmitty
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C series hp

Post by dsmitty »

Hey guys, hoping for a little info. I have an '88 200 that I could not be more happy with. I am just curious as to what others think (or know) what the stock and modded hp numbers are for these. Crank and wheel. I have a handful of bikes, xr 500 down to a kx 100. My kdx is my favorite. I've seen that the H series were advertised at 37 and I'm willing to bet the air cooled are a bit lower. When mine was stock it felt to me like around 30ish. I know I know these numbers don't mean anything but without opening a can of worms, just wondering what others think. I did the 240 kit, reeds air cleaner pipe etc. etc. and I just love this bike. thanks for any input. Go green!
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Re: C series hp

Post by s10gto »

I would say your about right at 30hp. I know the aircooled non powervalve 250's were 33hp. That baby must rip with that 240 kit. :supz:
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Re: C series hp

Post by dsmitty »

It is so cool. Not a whole lot more up top but man it's got low end like a built 4 stroke with the 2 stroke snap. I love lugging around with my xr500 but it's just so dang heavy. Kinda why I bought a kx100 (I'm a little guy, 5'6, 165) and a yz250. But I gotta be on the pipe. Not good with trees rocks and roots. I haven't ridden my other bikes since the rebuild. Probly will in the spring when I take the kids to some tracks but for messin round in the woods my old kdx is PERFECT. Even when I did the basic mods before the bore kit it really made a difference. Is it nuts to think that with basic mods these old bikes put out mid 30's or close to 40 HP?
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Re: C series hp

Post by KDXGarage »

A stock 1986 - 1988 KDX200 is probably around 25 or 26, with an E or H being around 28. Dirt Rider had the 1986 I think, on the Kerker dyno, 24.6.

Someone on another site had the standard mods and got 30 or 32, something like that, out of an H model.
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Re: C series hp

Post by dsmitty »

Thanks Jason. I'm curious about the 240 kit too. It really feels like most of the gains were in torque. My yz 250 has gobs more power (of course) and speed but for my 49 year old azz I'm WAY happier on the kdx. Lighter, lower and GOBS more low end. Ya HP numbers are for conversation sake and curiosity. Based on that dyno test, I get to thinking mine (before bore kit) felt like 30ish is because it had 12\50 sprockets! (Came that way). I've since put the stock 13\48's on and the 240 pulls them easily down low.
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Re: C series hp

Post by KDXGarage »

I guarantee you my KDX was making about 40 HP with the Pro Circuit pipe and silencer on it. More info below the pic...

<img src>http:kdxgarage.com/dynorun2-12-18-14.jpg>








































my KDX250 that is. :busted: :lol: :mrgreen: :supz: :partyman: :bravo:
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Re: C series hp

Post by fuzzy »

Hard to tell with a 240. It may be the same HP, but the torque curve is where the major difference will be.
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dsmitty
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Re: C series hp

Post by dsmitty »

40 HP is amazing. I've read and always thought it is possible. You must have more mods than the PC pipe and silencer. :) like you said, some one else got 30 32 with standard mods. Just curious cause i'm gonna buy a couple more. (Liquid cooled newer ones). After my kids (23 and 17 yrs old) rode my "custom" aircooled, (240, lowered, slightly shaved seat), they want one for themselves. But a "cool lookin newer one". That is suspended and liquid cooled cause they want to do more than just " putt around all day" like the old man. Gotta luv it. :) What does it take to get 40 HP, and any reliability or heat issues?
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Re: C series hp

Post by KDXGarage »

Re-read the bottom of my post, it was a joke, as I put not just "KDX", but "KDX250". :grin:
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Re: C series hp

Post by linny »

Has anyone seen significant improvement with a flatslide carb?
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C series hp

Post by kdx87 »

My brother uncovered an old motorcycle magazine the other day from 1984, they claimed the 1984 kdx 200 put out 30hp, not sure how accurate but my 1986 kdx that I use as a daily commuter isn't far off from my mates drz400e in regards to power. That is stock other than a tingate racing muffler, never heard of them either.
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Re: C series hp

Post by KDXGarage »

NOT possible as far as at the rear wheel. At the crank maybe. Generally, "we" are talking about at the rear wheel.
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C series hp

Post by kdx87 »

Yeah, sounds about right. One of my mates had a klx250 and my 86 could easily take it no problem, I guess the green machines have a huge weight advantage in their favour.
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C series hp

Post by kdx87 »

a piped aircooled could be putting 33 at the crank? the pipe is a huge change
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Re: C series hp

Post by fuzzy »

Linny, I think many have swapped the mikini out for a PWK.
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