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Can I do this?

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A question to all the kx250 experts out there.  First my bike is a 99 kx250.  I'm currently in process of a complete rebuild on the engine.  I have the bottom end rebuilt with the 98 transmission upgrade.  I'm waiting on an inner clutch cover because apparently the first owner had an o chit moment and cracked the cover.  It looks like its been welded but it didn't hold.  I'm waiting for a replacement from rocky mountain atv at the cost of 200 big ones.  Now here is my question.  I picked up a spare kx250 last year which is a 2002.  I've had the bottom end apart to look at it and I think with some change over I could use the cover for my 99.  Whats the possibility of this?  I think I would have to change to the outer drive gear on the crank and use the power valve actuator and the water pump from the 2002 in order to use the inner clutch cover.  Any body know if this is correct?  Thanks for your time and help on this guys!

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I'm sure in 2002 the kick starter shaft was increased in size. Seen you had no problems swapping over covers, Maybe your 2002 isn't a 02.  One of my KX250 I've used the 02 Gears and clutch and the ratios are way better than my 99. Good luck with your 99, great bikes 

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I had to use the kick start off the 2002 when doing this so you are correct and the kick start lever.  I believe if I wan't too I could change the primary gears (3:1) as well but I'll run the 99s (2.7:1ish) for now.

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Yes you can run the 02 trans in the 99 with either primary gearing you want.

Ed

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Actually with the 98 first they work out to be almost the same. The 02 is a higher geared trans with a lower primary ratio and the 98 was a lower geared trans with a higher primary ratio, IMO not worth changing. I have gone to the 91-94 KDX trans in all of mine now.

Ed

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HSV434 so can you run the 02 transmission in the 99 and just change the primary gears?

Short answer yes but will need the PV governor gear off the 02~.  Your water pump spur gear is the same as all 92~04 models (59051-1248). 

If you have the 02 shift forks that helps take care of one other issue with the 02 gear swap. the 99 model 5 gear wheel fork hits the 1st gear when shifting into low. I just grind a little :ride: bit of clearance into mine  

IMHO the 02 have a better spread of ratios, Same as Honda CR's but not as low as just 98 1st swap which you have done.

Enjoy your new setup you will be happy with that. :thumbsup:  

I've been inspired by Ed's 91~94 KDX that I've done that swap to a third KX project that's is to be completed soon. ;)

Edited by hsv434

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I've been inspired by Ed's 91~94 KDX that I've done that swap to a third KX project that's is to be completed soon. ;)

 

hsv434 I am glad to hear the KDX swap has worked out for you :thumbsup:

 

Ed

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Biggin69camaro Where are you at in Utah, I live in Elko Nv.

Ed

I live in Vernal, Utah.  

 

Thanks again for all the feedback guys.  I would like to try the kdx tranny swap in the future as well.  Its been fun trying some of this stuff out and seeing the benefits.  I'm still waiting for my cylinder to get back in order to try it all out..

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I live in Vernal, Utah.  

 

Thanks again for all the feedback guys.  I would like to try the kdx tranny swap in the future as well.  Its been fun trying some of this stuff out and seeing the benefits.  I'm still waiting for my cylinder to get back in order to try it all out..

 

Well Biggin I don't go to Utah much but back in 2010 did go and ride 5 miles of hell and some of Moab on my KX of coarse. If we get a chance we should get together for a ride. I do good rides in Idaho every summer if you would like I will guide you on a good ride up there. Here is a thread I did on a ride up there if you haven't seen it http://www.thumpertalk.com/topic/571177-idaho-ride/. And here is the KDX trans swap thread to for you to check out http://www.thumpertalk.com/topic/902713-91-94-kdx-trans-into-a-01-kx/.

 

Let me know if you think about coming this way or up to Idaho for a ride, it usually doesn't take much to get me to go if I have the time. If we do happen to get together ever you can test ride a KDX transmission :ride:

 

Ed

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That would be awesome!  I'll be honest with you I just started riding last September so I'm still very novice, but I'll hit you up if I'm ever that way.  Thanks again for all the help.

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