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'95 through '98 kx250 power comparison?

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Just curious if anyone has any experience with the '95, '96, '97 and '98

kx250's that could compare the power characteristics between them. Obviously, everyone raves about the '98 being the best, but is the '95 through '97 significantly weaker or lacking in low end etc. compared to the

'98? I'm asking because I am considering trying different ignitions, carbs and pipes on my '02 kx250 to try to get more low end grunt out of it, and don't want to waste my time and effort on a certain year if it was known to be a top end power oriented motor. I have a '96 cylinder at the moment to try, but I can't seem to find much info on what kind of power the '95~'96 kx250 made. Thanks in advance for any help or info.

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I'm going to mess around with one of my 2000's like that. Ed (no1clyde) says the 98 ignition works real good in the 99-02(?) models. If he doesn't reply just shoot him a PM.

I had a brand new 98 and the torque is similar to my 2000. If I miss a shift in a berm or get in some trouble I can just power out of it or dab the clutch real quick. The 98 just seemed to have more horsepower. IIRC, the 97 was close in power to the 98.

I installed a 2002 PC works pipe on my other 250 which moved the power slightly to the top end. I really prefer the stock pipes for both 98 and 2000's.

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Thanks for the info, I have an '02 right now, and my previous bike was a '94, and I have to say that I liked the low end grunt and overall power of my '94 better than my '02. So that (along the info I have learned here on TT) has got me all fired up to start experimenting with cylinders, ignitions, carbs and pipes. I already scored a '96 cylinder cheap on ebay, and there is some '95 ignition parts on there cheap right now, but I never really heard much about how the '95~'96 bikes were power-wise. If it's really worth it, I will hold out and wait for some '97~'98 parts to show up and work with them, but if the '95~'96 motors were good also, I can get started sooner. Thanks again for the help.

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When I approached Ed with the same situation he said you'll get more gains from the ignition swap than anything else. My ultimate plan would be to have a complete 98 motor/ign in my bike, but I may settle for a cylinder/ign combo.

Ed posted alot of info on this forum before.

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Yes, I have most of Ed's posts saved on my computer...lol. His info is great, but he has worked with the '98's to '02's from what I have read. I was hoping someone could share some experience with the '95~'97's. But I might just hold out for '98 stuff, since it seems to be the crowd favorite so its probably the safest route to spend some money and not be disappointed.

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If I remember the reviews '97 and '98 were very similar but '98 had better brakes and sightly differrent suspension set up and ignition/ porting tweaks. The '98 was just one of those bikes where it all came together very close to perfect. If I was doing what you were doing I would hang out for the '98 electrics but acording to Ed the cylinders are all very similar. If you are going to have the porting tweaked that will definitely help you get to the characteristics that you are after. If the chrome is tired on the '96 that may be a good excuse to send it off to get ported and replated at the same time :)

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Thank you for the response. Yes the chrome on the '96 is definitely ready for a re-plate, if I used it I would get that done. The powervalve parts may need replacing also, I haven't tore the cylinder down yet, but the powervalve parts seem very loose and sloppy in the cylinder. When I had my '02 apart to clean the powervalve, everything fit very snug with very little play.

I was always under the impression (and I could be completely wrong here) that porting was almost always for upper rpm power improvements, that removing any material from the ports would likely hurt low end power but improve the top end, an acceptable trade off if you were a fast racer and wanted all the top end power you could get. I want low end grunt, (which my '94 seemed to have a lot of) so I hadn't considered porting as an option.

I probably will wait for the '98 electronics, but I wonder still if the '96 cylinder would be good enough (compared to a '98 cylinder).

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I have a 1995 in my garage right now. It makes all low-midrange power. Its strong like a brute, and does not like to rev high.

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OK the 98 pipe helps with low end too. I know most people like the 98 the best but I have 4 friends with 2 98s and 2 97s, the 98 dosen't rev as high as the 97 so it really is up to you what you want. The carb you have will work fine with other jetting in it. If you use a 98 ignition it would work fine by not pluging the TPS into anything because there is nothing to plug it in to. If you use a 95-97 ignition you don't plug anything in to the carb because there isn't any to plug in but you should put a pluged powerjet jet in the carb and then use the matching jetting. If you leave the powerjet jet unpluged you would need leaner jerring as it would flow fuel all the time and not shut off. Buy stock pipes off oebay of different years to play with 95-02 will interchange.

Yes you can have a cylinder ported for low end by a good tuner. For reeds I use stock cage with carbon fiber reeds of a Boyesen rad valve myself but everyone has there own ideas. Also I have found the 99 ignition a nice split between highend and lowend and om using that on my 300 and my 310 and so far I have left the 02 250 stock and it seems to run well.

On any given motor I try every reed and pipe combo I have laying around. I will also play with ignitions but it is mostly the 99 or the 98 setup. Ebay has been good to me, I know some have had bad luck but mine has been good. Really look at the pictures and ask for cylinder casting #s to know what you are bidding on. Powervalve needs to match the cylinders too as there were some changes thru the years.

Good luck

Ed

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02YZ426, that is the same kind of power I remember my '94 making, and I liked it. My '02 that I have now seems much weaker (electric-like) down low but with a strong mid-range and decent top end. I liked the '94 better. Thanks for the info.

Ed, I have a non-power jet carb that I can use if I go with a pre-'98 ignition, that way I can skip dealing with the power jet all together. I got the carb off ebay, it was advertised as a '95 kx250 carb but I think it was actually a '94 because it doesn't have the quad vents. It's still a Keihin pwk38 so it will be fine if I use it and jet it right. I'm not sold on that the powerjet really helps anything, and same goes for the TPS. All this fancy evolution in carb/ignition trickery and I can't tell the new stuff works even as good as the non powerjet/tps bikes did..lol.

When you say your friends '97 revs higher than the '98, is that at the expense of some low end power, or do you think the '97 is as good as the '98 on the low end and just revs a little higher? If thats the case then I can use a '97 ignition if I come across one on ebay. (I noticed kawasaki advertises the '97 ignition specs as 14* BTDC @ 6530rpm, while the '98 and '99 is 11* BTDC @ 7000rpm, so they are definitely different.)

Thanks again for all the information, it is definitely appreciated.

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Most of my friends like the 97 more that the 98 but most people feel the other way. I like them both. The 97 has an ignition much more like your 94 than the 98 does. The stator is alot different, I think it was changed in 98 to run the powerjet. If you can get it cheap you would most likely like the 94-97 set fine. I have ran the 98 ignition on my 310 that is a 02 based motor and it worked great but now I have the 99 on it so it will rev better. On that note the 98 and the 99 use the very same cylinder but the ignition, pipe and jetting changes make them run quite abit different, the 99 revs and the 98 torques.

Ed

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not to rob this thread but i have a 96 kx 250 that i have been trying to tame down,it has hot rod, wiesco piston,fmf gnarly,v force 2 reeds,11oz fly wheel weight,13 47 gearing,bike goes good,to good.is there a ignition that would smooth the power out that i could get.and i have a boysen rad,would this be a better reed cage for my bike.im just trying to calm the bike down. tired of fighting this beast.im trying to lighten the 2 stroke snap that it has.thanks :):D

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Well one thing you can do to tame the power is jet it a little rich. If you really want to tame it unhook the powervalve so that it never opens. The Rad valve may be better for you, try it.

Ed

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Kawie, what kind of power does the '96 make, is it more of a low-end grunt torque motor or is it mid range to upper rpm power that you are trying to tame. I have a '96 cylinder that I am trying to decide whether to use or not. I want low end power but I don't know what the '96 was ported/designed for. Thanks for any info.

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I was always under the impression (and I could be completely wrong here) that porting was almost always for upper rpm power improvements, that removing any material from the ports would likely hurt low end power but improve the top end, an acceptable trade off if you were a fast racer and wanted all the top end power you could get. I want low end grunt, (which my '94 seemed to have a lot of) so I hadn't considered porting as an option.

I probably will wait for the '98 electronics, but I wonder still if the '96 cylinder would be good enough (compared to a '98 cylinder).

A good engine builder can port to suit either low end or top end power band. To modify a MX ported engine for off road a tuner will typically remove material from the base of the cylinder which effectively lowers the ports. Mods need to be made to the cylinderhead to accomodate this.

Combination of porting, Vforce reeds, ignition and a flywheel weight will have you a very 'enduro' orientated machine.

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rbreak,im not sure still too new to this stuff.if what u mean is in each gear it doesnt do much untill the power valve opens.it just kind of goes then all heel breaks loose then i have to shift,stock gearing is to close together though.seems like u shift then u have to shift again.

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I have a 1995 in my garage right now. It makes all low-midrange power. Its strong like a brute, and does not like to rev high.

mine is all on top. nothing at low and mid.

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Kawie, thanks for the info. That "all hell breaks loose" is kind of what I'm trying to get out of my bike, or at least some of it. My '02 is electric smooth down low (not a good electric smooth, more like a not enough low end power smooth), then it has a decent mid range bark, but nothing to get too excited about, then a sort of flat top end pull. My previous bike was a '94 kx250, it had much better low end power, and the mid and top where at least as good as my '02. I'm trying to find a way to get some of that low end power my '94 had out of my '02. I have a '96 cylinder that I'm going to try, along with an earlier pipe, ignition and carb and see what I can come up with.

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mine is all on top. nothing at low and mid.

If I line up next to 39 riders like you this weekend, I'll be in good shape. :)

Try to hold a steady throttle on your starts, not "blip...blip...blip." Use second gear to start out with. And get your right foot on the peg! That's why the ass end is all over the place.

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