KLX300 Chassis Swap

[Jpease]

Well I have a 1997 KLX300R Here in Ca they are no something most people want so this leaves me to make it a bike that I would like!

So far I have put the 05 front and rear fenders from a 450 number plate and fork guards.

I want to race again and well this bike wont cut it frame wise as the head stay will bend and or break off OUCH not willing to do that. Since times are tough I feel as if I'm stuck with this bike as I cant seem to sell it to replace it so Im thinking of doing a kxf frame swap! What do you guys think?

I have a line on a 05 kxf frame that I think will work with little to no modification.

Anyways here pics in its current form.
Also want to say thanks to OEM-Cycle for all their help!!!

[Tardboy]

Whoa!
I'd love to see how this turns out.
Please keep me posted

[Sandblaster]

Hey Jpease.
Thanks for the post.
Putting a KLX300R engine in a KX250F Chassis.
This is a very interesting build.
I believe this build has some real potential.
I don't have a pair of klx300 engine cases to check fitment but I do have the frame and one case which should give us some sort of idea.
I'll post my findings tomorrow.

[Sandblaster]

Ok, here is a pic of the KLX300R left engine case sitting in the 05 KX250F steel frame and attached by the swing arm pivot pin:



Here is another showing the back area of the case:



As you can see, the engine mounts will have to be completely redone.
That's not a big deal.
However, the area that is shown as the back of the left engine case has a frame brace that I believe will be in the way so it will have to be removed and re-located.
Still not a big deal if you can weld and cut tubing.

Here is a pic of the area where the cylinder and head will fit:



With the engine tilted up in front it's hard to say how much trimming and fitting will be required to make room for the head and head cover.
As a minimum I believe the head stay mount will need to be removed and re-located.
Again, not a big deal if you can weld.

Here is a pic showing the over all frame with the case in it:



Some of the things that aren't as obvious that I ran into with another conversion I am working on is the swing arm pivot pin bolt size is larger on the KX250F then the KLX300R engine. No biggie, you will need to drill the cases out a little larger.
The other thing that I can't check because I don't have the other engine side case is the swing arm width as respects to how wide the area is for the engine to sit inside of.
If you measure how wide the engine is where the swing arm goes, I will check the KX250F swing arm to see how wide it is.
I'm betting it is fairly close.
I had to grind a few thousands off my bushings on my project bike to make it work but it was very easy to do.
Another thing to look at is the air box boot, cdi mount, coil mount, radiator hose configuration, how the header will wrap around the frame, how to attach the exhaust arrestor or muffler, and kick start location to insure that it can clear all the frame components.
I'm probably missing a few other things but those are the ones that hit me on top of the head.
Generally speaking I think this is a viable conversion.
For those of you who ask why would you do this, not everyone want's the power and torque curve of a 250F or 450F engine.
Some people enjoy the torque of the 300R engine but want modern suspension so they can beat on the bike without worrying about the head tube which holds the triple clamps from popping off or bending their forks
Let us know what you come up with.
SB

[Jpease]

Thank you soo much SB.

Ill be calling you latter today. I need to put some Major thought into this.

[Jpease]

Well after lots of consideration I'm done with this project. Bike is currently FOR SALE Will make one hell of a deal and will meet half way for sale or trade. SB Thanks for all your help on this bike its much appreciated you have earned a customer for life.

[Sandblaster]

No problem.
If we can help on future projects, feel free to hit us up.
Thanks!
SB