Page 2 of 6
Re: BUILDING A KX500AF with a 2007 KX250F chassis
Posted: Sun Jun 24, 2012 2:02 am
by Sandblaster
You can make your own frame rails but I ordered a set from JFABMOTORSPORTS
2880 Jackson Rd
Wentzville, MO 63385
U.S.A.
jerrysfab@centurytel.net
Jerry requests you contact him Via Phone at the shop to discuss any services 636-673-7102
If you are going to use these frame rails from JFABMOTORSPORTS order them sooner rather than later as Jerry is very busy.
To tune up the rail guides and the rails I used a small hand file.:
With just a few minutes of filing all the edges were cleaned up nicely.

Re: BUILDING A KX500AF with a 2007 KX250F chassis
Posted: Sun Jun 24, 2012 2:06 am
by Sandblaster
Since I had to cut some of the length off the new frame rails I used the scrap piece to test fit the new rails.
To make it fit smooth and clean I filed two of the four corners from the test piece so that it would fit the radius of the frame guide:
Once I filed a small bit from the two corners I was able slip the test piece in easily.
Once I tuned up both frame rail guides I set the frame straight up to look at how well the new frame rails would fit.
Then I noticed that the frame rail guides are actually pigeon toed inward.
I took a look at the original carriage and sure enough the frame rails were bent to compensate for this.
It's hard to see but if you look close you will see the original rails are bent out.
Since the replacement rails are straight, they will not make full contact all the way back.
However, this is not a problem as there is plenty of weld surface.
Re: BUILDING A KX500AF with a 2007 KX250F chassis
Posted: Sun Jun 24, 2012 2:08 am
by Sandblaster
So, you remember this guy?
Well after a visit with Mr, Sawzall and the grinder, it looks like this:

Re: BUILDING A KX500AF with a 2007 KX250F chassis
Posted: Sun Jun 24, 2012 2:10 am
by Sandblaster
This gives you a really nice purchase point for the frame rails:

Re: BUILDING A KX500AF with a 2007 KX250F chassis
Posted: Sun Jul 01, 2012 3:29 am
by Sandblaster
The current plan is to have the frame temporarily tig welded in a few places to hold everything together.
Once I make sure it is exactly how I want it then I will take it in and have it professionally welded.
I should have the temp job done sometime around 7-3-12
I'll post pics..
Re: BUILDING A KX500AF with a 2007 KX250F chassis
Posted: Sat Jul 07, 2012 3:50 am
by Sandblaster
The frame carriage has been tacked into place.
I will need to drop this off at the aluminum welder sometime next week.... 7-15-12
Re: BUILDING A KX500AF with a 2007 KX250F chassis
Posted: Thu Aug 02, 2012 6:43 am
by Sandblaster
I just got the frame back from the welder tonight.
I'll post pics tomorrow.
Re: BUILDING A KX500AF with a 2007 KX250F chassis
Posted: Fri Aug 03, 2012 9:32 pm
by Sandblaster
Finally.
Here is some pics of the frame after ouR first trip to the weld shop.
We are having it welded in 3 steps so we can get things a little more dialed in rather then trying to weld it all at once.
It was Mig welded using 5356 filler.
The frame rails are made from 6063 aluminum.

Re: BUILDING A KX500AF with a 2007 KX250F chassis
Posted: Sat Aug 04, 2012 6:48 am
by Sandblaster
So, next on the list is engine mounts, CDI mount, Coil mount, radiator mounts, modify the fuel tank, and modify a left side radiator.
After that, bolt it together and see how I like it.
Re: BUILDING A KX500AF with a 2007 KX250F chassis
Posted: Tue Aug 14, 2012 6:46 pm
by Sandblaster
I ordered a head stay from:
JFABMOTORSPORTS
jerrysfab@centurytel.net
2880 Jackson Rd.
Wentzville, Mo 63385
USA
Here is what they look like:
I'm thinking about doing away with the stock head stay that is molded into the head.
More on this later.