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what are the improvements in the last 20 years? how are new two strokes better?

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Just wondering. I still own the KX250 I bought in 1988 and hare scrambled for six or seven years. Along the way it got a big bore (300) kit, a heavy flywheel and a revalved suspension. It did quite well back in the day. It is a tractor and will idle up any hill in any gear pretty much. Awesome for tight BC bush riding.

I am now restoring it after it sat in the back of my shop for the last 20 years. So other than a wider ratio transmission and maybe better ergonomics how is it different from a new say KTM 300XC? I see an electric start and a six speed transmission. What else is different. The four strokes have obviously come a long way but I'm not seeing how a new two stroke is better than my old beater. What am I missing? Way more power? I see it weighs the same. It's a serious question. I have been out of the game for a long time and I really was surprised to see that two stroke development seems to have stopped pretty much.

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Main improvements would be :

Suspension ( although you have revalved so....)

I think the KTMs have adjustable powervalves

Weight reductions

18" rear wheel

I'm guessing a dedicated 300 for offroad would be better than a bored out MXer but I wouldn't be sure as I haven't ridden either

They might be a few more, but the KTM 300xc is generally the go-to bike for off road.

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Better powervalve design.

 

Better suspension

 

Better carbs (Keihin PWK for example)

 

Good oils (I suppose been around for a while)

 

Electric start

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Suspension and gear ratios mainly. Of course if its been bored to 300, you can pull taller gearing, which spreads them a bit. And as said above, suspension can be modded or swapped. Better carb is an easy swap, too. KTM's adjustable powervalve is useful, but not even close to necessary. "Red valve, screw flush" seems to be the same setting most people use, except on mud races. Sending the cylinder off to be ported and swapping to a PWK36 may make up most of the engine differrence. But if its already a tractor, its more than enough for harescrambles.

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I doubt the ergonomics on a new KTM are better. I would have no issues rocking an '88. Plus people hate getting passed by it. And I can pretend to have bike problems when I lose.

 

Disagree.

 

I put a shortass seat on my KTM and it feels like a honda 2t.

 

Oh, and I've ridden an '02 KX250, you DONT want to compare how they steer (if you're a KX rider).

Edited by BushPig

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So really no development of note then. While I was riding I saw front disc, then rear disc, water cooling, single shock rear suspension, perimeter frames, aluminum frames, seats that climbed up the fuel tank.....but really other than graphics it seems like the two stroke motocross type bike was kind of perfected years ago. Graphics and plastic design is way better now, and electric start is a big one, but I don't see much else. four strokes on the other hand were really not very good back then. Heavy unreliable pigs with play suspension. I guess that is where all the development dollars went. 

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i'd say the biggest diff is that a new ktm will work fine right out of the box instead of having to revalve it and do all kinds of motorwork and customization like you have done. MX bikes may not be hugely different, but now you can get a real offroad bike without having to build it yourself from an mx bike.

 

I don't know much about ancient bikes. I had a 2007 kx and I found the motor to be very durable and reliable. it would have benefitted from an overbore kit to give it more torque like an xcw. If you can get 150-200 hrs between top ends on your old beater, then keep riding it.

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88 to 89 model year kx250 is the basis for the 91 to 94 kdx250 motor. Source one of these kdx250 transmissions and drop it into your motor. Now you have a kx250xcw :thumbsup:

I had a husky wr300 model year 2014 but switched back to an "aged" 99 kx250 and have no regrets.

Edited by shrubitup
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Bike tech made tremendous progress up to about the early 2000's.  After that I would say the improvements range from incremental to none at all.  Stewart and Carmichael kicked a lot of ass on the L series KX.  McGrath did very well on the late 90's Yamaha.  Thats the level you can ride at on these machines.  It may be a little easier to go fast on a brand new air fork four stroke but thats not to say you can't do it on an older bike. 

 

I have been on an 03 KX since 2002 and I see no need for a newer platform.  I don't like four strokes, fuel injection or aluminum frames.  If I were going to pick up a newer bike it would have to be a KTM but for all of the bizarre failures I've seen on them over the years I don't think I would feel confident on the orange bike.  I've never seen a Japanese bike break in half at the steering stem and there are a lot more of them out there than KTM's. 

Edited by turbo dan

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  I've never seen a Japanese bike break in half at the steering stem and there are a lot more of them out there than KTM's. 

 

yamaha_zps635d806f.jpg

 

Now you have. Hope that helps.

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I've seen aluminum frame Yamaha's break frame spars.  Thats not uncommon.  Notice that in that picture the steering stem is intact.  I was rather specific on that point.

Edited by turbo dan

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I've seen aluminum frame Yamaha's break frame spars.  Thats not uncommon.  Notice that in that picture the steering stem is intact.  I was rather specific on that point.

so you're saying that there's a big difference in just exactly which part of the frame breaks when a bike breaks in half? 

 

lulz.

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I've never broke a frame or blew up a motor. Am I doing it wrong?

I've never killed a dirt bike yet... can't say the same about snowmobiles though. :smirk:

 

If my insurance company knew half the shit I do... :lol:

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