KX5TM Conversion

[Afterthought]

Well Guys very happy to have found this forum. I currently ride a KTM 300XC street legaled. Love two strokes. Always been fascinated with the idea of the KX500 engine in a newer frame that feels like my KTM. I see alot of CR500AF builds but honestly Im not big on the aluminum frame or the cr500 engine. many discussion support the CR5 but I don't think the KX gets the respect it deserves.

Purchased a 2000 KX500 from a guy who's wife told him he needed to sell it, he had gone for a wild ride on it and had some real bad bruises. He said hoped I knew was I was getting into. I am already well aware that I am an idiot, so I proceeded with the sale. I initially purchased this bike just to use the engine out of but then later decided the bike was too good as is.  I'd hate to tear it apart. I love the way those older bikes look. So, I decided I would have to source a different engine for the build. So at this time I have finally found a second engine and have that on the way.

So starting a thread here to track my progress the list will change as time goes on.

Plans may change but here is what I have to use for starters.

Parts from 2012.5 KTM "Factory Edition" 450SXF
-Frame
-Triple Clamps
-Fork
-Shock
-Linkage
-Swingarm
-Airbox
-Front brake handle, caliper, MC and line
-Rear brake caliper and MC (no line)
-both radiators
-New plastics
-Subframe (this is from a 450 XC not sx)

Now from a 2000 KX I have
-Engine
-Coil
-Carburetor
-FMF Gnarly pipe x2
-Stock Pipe x1
-FMF Silencer
-Extra frame if needed for Mock-up or to make a template (not to be cut up plan is to use to powdercoat restore the 2000)
-One extra airbox
-Misc set of extra bolts

So still have some odds and ends to pick up.
wheels
handlebars
Misc brake components
Bolts here and there


Still have alot to figure out
May add decompression head
Convert clutch (would like to do a hydraulic actuator on that)
Will 450 airbox work, maybe use stock 500 air boot in that box?
Will the 450 XC subframe work
Will 450 radiators work

Going to start reading through threads not and figure out what the hell is going on. I kind of have the cart before the horse here but I'm determined to get this done. Any advice is appreciated!

[reklessj]

Welcome Afterthought!  Sounds like a bitchin project, there are all sorts of conversions on here and lots of very knowledgeable members.

[umberto]

Welcome to the site Afterthought.  FMF did this conversion a year or so ago, and they featured it in MXA.  MXA really loved the way the big motor worked in the KTM frame. 

Being a steel framed, carburated two stroke bike, you should only have to mess with motor mounts and pipe fitment.  I used a CR gnarly pipe on mine, combined with the flange from the K5 gnarly I had for my motor.  Be sure and post pics as you go!

[Afterthought]

Welcome to the site Afterthought.  FMF did this conversion a year or so ago, and they featured it in MXA.  MXA really loved the way the big motor worked in the KTM frame. 

Being a steel framed, carburated two stroke bike, you should only have to mess with motor mounts and pipe fitment.  I used a CR gnarly pipe on mine, combined with the flange from the K5 gnarly I had for my motor.  Be sure and post pics as you go!

I did see the swap they did. Here is a link to the article if anyone is curious. http://motocrossactionmag.com/bike-tests/we-ride-donny-emlers-kx500ktm-250sx-hybrid-two-stroke-project-bike
I am not sure if I am going to have to purchase a CR500AF designed pipe or maybe be able to make something happen with the pipe I have.

[mikectanker]

I risked $400 on the kx500af pipe that service honda sells. I worked well.
Look at my RM250  build on here. It may be of help to you.

[Afterthought]

I risked $400 on the kx500af pipe that service honda sells. I worked well.
Look at my RM250  build on here. It may be of help to you.

I think I am going to do the same. I don't want to cut my 89-04 500 FMF pipes all up those cones can be very tricky to make and I'm not an engineer, likely would never perform well.

[Afterthought]

Some pics of the progress.

For those who are curious, This is how the stock mounts compare on my '12.5 450 frame. (With the pivot bolt through the case)



Getting chain spacing lined up. This is just to get it in the ballpark, then later had to come up with a more accurate system using the straight edge of the flat bar



Making new mounts






Engine removed from donor bike

[Foxx4Beaver]

For those who are curious.

that should never even be a concern!...I'm thinkin everyone on here is always curious about everyone's build...good ways to pick up on some possible new tricks and ideas.

lookin good.

[Afterthought]

For those who are curious.

that should never even be a concern!...I'm thinkin everyone on here is always curious about everyone's build...good ways to pick up on some possible new tricks and ideas.

lookin good.

I have built some cars in the past and it gets tricky remembering what you used and why, especially spacers and things, thicknesses, fitment, So I am going to try and track that stuff here so I have a place to refer back to if i need to remember something. hence the measurements on the case!

[KTX]

That is a very cool project.  I have a 2007 KTM 450SXF with a TMR 99 KX500 engine.  Its almost to much fun to be legal.
If you have any questions I will try to answer anything I can to help you.  

My Ride:

http://www.kxriders.com/forums/index.php/topic,16230.0.html

[Anchefonk]

Hello!

How did you solve the issue with the air boot being to long?

Regards.