Anybody ever convert an 05 or o6 KX250 2stroker

[Rd]

Has anybody her converted an 05 or 06 KX250 two stroke. It is probably similar to all the other kx250 builds, but I saw no threads.
Currently there is an 05 and a 06 KX250 for sale locally and the sellers are having a hard time getting rid of these fine machines.

[sandblaster]

I haven't seen that conversion but I bet it would be a lot easier then using a 4T frame.

[motopunk]

what a question..

look here:  http://www.servicehonda.com/kx250af.html 

 

converting the 125,250 are the same steps as the 500af , but i also say, its way easier, because you can use the stock exhaust or buy all kind of aftermarket pipes. for the kx500af is it always a modified honda cr500 exhaust.

[81cr450]

kx500af is it always a modified honda cr500 exhaust.

You say that like its a bad thing, 15 years since a k5 pipe has been designed. How bout something from this century, maybe even this decade.

http://cpiracing.com/shop/index.php?route=product/product&path=63&product_id=238

Built for that 200 degree duration

[motopunk]

kx500af is it always a modified honda cr500 exhaust.

You say that like its a bad thing, 15 years since a k5 pipe has been designed. How bout something from this century, maybe even this decade.

http://cpiracing.com/shop/index.php?route=product/product&path=63&product_id=238

Built for that 200 degree duration

where do you read in my post that its bad?    ...  the k5 engine runs well with this cr500 pipes...  but you cant istall it without the welding-mods to fit to the kx500 engine and the used conversion frame... thats the point..  

[jBernard]

73hp.....seriously?

8.5hp MORE than another brand. i have seen their dune pipe before and obviously they are gutless down low and screamed up top. but i wish they had better data of lower 2-5k rpms on those dyno charts, looks like it was skipping or something on the dyno, since graph isnt smooth.

[The Flyin Hawaiian]

The 05-07 KX250 2t chassis swap should be very similar to the 03-04 swap. I built one using a 04 chassis. I also have a 07 KX250 and have eyed up the frames and it looks pretty straight forward. The 05-07 frames are narrower at the footpegs than the 03-04 frame but I dont think that will cause an issue. 

[81cr450]

73hp.....seriously?

8.5hp MORE than another brand. i have seen their dune pipe before and obviously they are gutless down low and screamed up top. but i wish they had better data of lower 2-5k rpms on those dyno charts, looks like it was skipping or something on the dyno, since graph isnt smooth.

They do runny s**tty down low but come on really quick. Just seem pig rich on the pilot & then clean right up as rpms just start to climb 

[Rd]

Thanks guys.
 Flying Hawaiian or anyone do you think there is any real advantage to using the 05 thru 07 bikes over the early ones
say 98 to 04 ?   Seems 99 and 00 are available at good prices fairly often.

[The Flyin Hawaiian]

I have a 03, 04 and a 07 KX250. The best handling bike of the bunch is the 04. When Kawasaki revamped the 250 in 05 they gave it a new frame, engine etc. It was a pretty good handling bike. They messed it up in 06. They brought the steering head angle in a bit and screwed up the handling. There is a thread here in the 250 section that addresses this issue. I just couldnt trust the front end to stick. Im hoping to fix my 07 this winter (thought I was going to do it last winter) by having the steering head cut and change the steering head angle. I would go for a 03-05 over a 06-07. My 04 250/500 handles great! Its strictly a tight woods bike and handles so much better than the old 500 chassis. I cant comment on previous year KX250s since I have not owned the 94-02s.

[KXDINO]

05-08 share the same frame part number 32160-0104-458 .I had both they share the same traits.

[motopunk]

i have used an old 93 kx250-frame for my conversion...
  on the frames 1990-2002 you have to made a front-headstay , cut off the back-headstay on the kx500-engine and work with a heatgun at the tank, for fitting with enough clearance over the bigger engine.
 
the 03- 08 kx250 frames have the headstay in the back, like the kx500 , which is also better for the 500 conversion .
 for the 94-03 frames you must also use the stock kx500 swingarm.(drill the bearing holes up to 28mm and use the 93 bearings and bushings and spacers between swing arm and engine.  
for the case to use the stock 250 swingarms you have to modify with welding and mashining.  

[KXDINO]

On my k5 in 2001 frame I used the 250 swingarm just drill the back of the engine and carefully grind the inside of swingarm to fit engine there plenty of info somewhere about measurements ,no big deal.

[The Flyin Hawaiian]

05-08 share the same frame part number 32160-0104-458 .I had both they share the same traits.

Good to know that! I have a few data sheets somewhere stating that there was a change in steering head angle from the 05 to 06. I almost bought a 05 frame for my 07!
 Also to the original poster. When using a 03/04 frame you need to use a 05 to 07 oversize fuel tank, if needed. I also shortened the headstay down on the head and redrilled the mount hole. I also cut the headstay mount off of the frame and centered it to the head mount for more tank (oversize) clearance.

[Rd]

Great info Thanks to everyone. You guys on this site are a wealth of knowledge.