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Which KX 250 for bottom end power?

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So I am wondering what years of the KX 250 cater to more bottom end power for a more broad power band. I know KX's are known for a hard hitting mid range. I had an 01 a few years ago and a 94 a long time ago that just felt more tractorable where I could lug it up to a double and crack the throttle and clear the jump unlike my 01 where it felt weak in the bottom end. I am a Kawi fan but have been considering an RM or YZ because they are supposed to have that more friendly power band that would suit my motocross riding style. Or could any year KX 250 be tweaked for bottom end by changing gears and tuning of the carb?

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You can bump the rear sprocket up a tooth or 2 get more acceleration, but you will sacrifice top speed. You can get a woods pipe which will move the meat if the powerband to low-mid, but will sacrifice top end power. IMO any 250 2t can be lugged then cracked wfo before most jumps and make it.

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Thanks Gas. That's what I was kind of thinking but I felt my 01 didn't have the grunt my 94 did but then again the 94 could have been setup for a woods bike from the previous owner. I have been reading the motocross action shoutouts and most results from 01 to 07 say that they lack a bottom end and are basically a more true race engine, especially the 06-07. I only ride motocross but would like to have the lazy mans powerband for when I don't feel like having a handful of throttle all the time lol.

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The 01 was not a low end motor.  The 98-99 would be more to your liking.  Great all around motors.  Not as much top end as the 05-07 but much more low-mid.

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Ive talked to guys on here and at the track that have ran a woods pipe for mx and lug it a gear higher. For them it seems to work but its not quite as lazy as a 450

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8 hours ago, GasMixer44 said:

Ive talked to guys on here and at the track that have ran a woods pipe for mx and lug it a gear higher. For them it seems to work but its not quite as lazy as a 450

I have never owned but I rode a 450 once and that is the ultimate lazy man's bike, I am actually considering selling my 250f for a 450. That woods pipe might be the way to go when I pick up another 250. I would rather have the bottom end vs top end.

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9 hours ago, turbo dan said:

The 01 was not a low end motor.  The 98-99 would be more to your liking.  Great all around motors.  Not as much top end as the 05-07 but much more low-mid.

My other concern was the chassis and suspension. I like that the late model KX's are slimmer and I would assume the suspension was better than my 01. But I have never sat on a KX newer than my 01 so I couldn't tell if the difference was that big or not. But I have always heard that the 98 seems the be the grand daddy of them all. 

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the 03 motor has pretty good punch off the bottom, even more so with a gnarly.

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the 03 motor has pretty good punch off the bottom, even more so with a gnarly.

I know the 03 and up are on the newer frames. Have you rode an older kx to compare with your 03 frame wise? I also did hear the 03 had decent bottom end power and maybe the 05 if read correctly.

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2 hours ago, IraqvetUSMC said:


I know the 03 and up are on the newer frames. Have you rode an older kx to compare with your 03 frame wise? I also did hear the 03 had decent bottom end power and maybe the 05 if read correctly.

I haven't.  Think the cockpit is maybe a little tighter on the 03 but I'm 6ft and it's not at all

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99 is going to give you a tranny with two second gears and no first, but that can fixed to be better than any other with a KDX trans.

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The 98 is the same motor as the 99 with a much lower first gear.  Best combo in my opinion is the 94-98 first gear, 94-99 2-3-4 and an 02-04 fifth gear.  I've never run the KDX trans but I did run the 94-98 first with an 03 fifth in my 99 motor.  Was a technical but straightforward install with no fabrication.  Everything drops right in place.  The KDX stuff is rare, more costly and an believe it requires fabrication.

Back in the day at one point I was on a 1998 KX125.  Replaced that with a brand new 2001 KX125.  Replaced two years later with a brand new 2003 KX125.  All of them are good platforms.  I had my best race results on the 01 but I always liked the feel of the 03.  Many years later I picked up an 03 250 and it never felt as good as the 125.  Didn't turn as well.  The M series chassis is slim and easy to move around on, and the plastic isn't as prone to snagging as the L series bikes. 

Best chassis of the bunch has been the 05 with a little bit of work.  I would not recommend it for bottom end power but it is the only KX250 I've ever been on that handles like a 125.  Add a set of 22mm offset triple clamps and it is a very good chassis, regardless of what the candyassed crybabies at MXA said about it.

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The 98 is the same motor as the 99 with a much lower first gear.  Best combo in my opinion is the 94-98 first gear, 94-99 2-3-4 and an 02-04 fifth gear.  I've never run the KDX trans but I did run the 94-98 first with an 03 fifth in my 99 motor.  Was a technical but straightforward install with no fabrication.  Everything drops right in place.  The KDX stuff is rare, more costly and an believe it requires fabrication.
Back in the day at one point I was on a 1998 KX125.  Replaced that with a brand new 2001 KX125.  Replaced two years later with a brand new 2003 KX125.  All of them are good platforms.  I had my best race results on the 01 but I always liked the feel of the 03.  Many years later I picked up an 03 250 and it never felt as good as the 125.  Didn't turn as well.  The M series chassis is slim and easy to move around on, and the plastic isn't as prone to snagging as the L series bikes. 
Best chassis of the bunch has been the 05 with a little bit of work.  I would not recommend it for bottom end power but it is the only KX250 I've ever been on that handles like a 125.  Add a set of 22mm offset triple clamps and it is a very good chassis, regardless of what the candyassed crybabies at MXA said about it.


So is there any difference as far as the chassis and suspension from a 94-98 vs the 99-02 L series or is it all the same just different plastics? My 94 had more bottom end grunt, maybe the gearing is what did it but overall the I don't see really physically much difference between the frames and swing arm between the 94-98 and 99-02. The suspension I wouldn't know.

Also would I be better trying to tweak the engine on an 03 and up with the new chassis style for a more modern suspension and slimmer bike or do you not feel a big enough difference to justify giving up the good 94-99 engines for the 03 and up chassis?

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37 minutes ago, IraqvetUSMC said:

 


So is there any difference as far as the chassis and suspension from a 94-98 vs the 99-02 L series or is it all the same just different plastics? My 94 had more bottom end grunt, maybe the gearing is what did it but overall the I don't see really physically much difference between the frames and swing arm between the 94-98 and 99-02. The suspension I wouldn't know.

Also would I be better trying to tweak the engine on an 03 and up with the new chassis style for a more modern suspension and slimmer bike or do you not feel a big enough difference to justify giving up the good 94-99 engines for the 03 and up chassis?

The differences from the K series to the L series are not tremendous.  Suspension wise anything from 96 to 01 comes with a 46mm KYB shock and 46mm KYB open cartridge forks.  Valving varied year to year but its pretty much all the same stuff.  In 02 they went to the 48mm KYB OC forks which are more of the same stuff.  Late 90's bikes came with progressive springs which you may or may not like.  Easy fix in any case.  The 01 and 02 forks were not valved very well, the 03 was better but really they all benefit from a good revalve. 

It comes down to condition really.  Whichever one is cleanest is the best candidate.  You could even work with an 01.  Cylinders interchange from 94-04, some require a few other things be swapped in conjunction while others will bolt right on and work.  A 98-99 cylinder, 94-98 first gear and a suitable pipe would be all you need. 

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I was thinking about finding a 94 for nostalgic purposes as that was my bike as a kid. Is there anything wrong with the suspension of that year? Would I be better trying to find a 98 or newer bike?  The gear changes sound pretty straight forward so I could work with that. Sounds like as for suspension it would be best off to go through the suspension on any older bike. I am not sure what a progressive spring is though. I did do the fork seals on my 01 and that was pretty easy. I would probably have my rear shock sent out though. My thoughts are stick with Kawi as I like the looks of the green scheme but I have also heard the 02-08 RM's and YZ's were the bikes to have for that era and I am half tempted to try a RM as I see lots of YZ's at tracks and pretty much have not had anything other than a Kawi. Another issue is if I am going to spend 3K or more it's going to be on a 450f fuel injected. I think the cost of the newer YZ's and KTM's 250t's are over priced since the YZ is basically the same bike as the 06. So ideally I would like to stay under $2,500 for a nice bike.

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Parts for the older bikes are going extinct.  Powervalves come to mind.  Cant get them.  Older bike is more likely to need them too.

94 has the early style cartridge with the check plate mid valve.  Does not work as well as the later forks. 

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Parts for the older bikes are going extinct.  Powervalves come to mind.  Cant get them.  Older bike is more likely to need them too.
94 has the early style cartridge with the check plate mid valve.  Does not work as well as the later forks. 

By older are you talking 90s only or even into the 2,000s? And thanks for the fork info

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Late 90's and early 2000's seem to be pretty good on original parts availability.  Early and mid 90's parts have been depleted and discontinued.  Of course this only gets worse and with the more recent bikes its only a matter of time before they're hard to fix too.

Find a nice one and work with the best possible starting point.

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So maybe doing a 94 might not be the best route to go especially if you've got money invested into it only to find you can't ride cuse of a power valve that you can't get or what not. So would you try to stay late model kx then or maybe consider another brand?

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