KX Guru Racing

It has been said by some Pro level riders that the stock KX500 rear brakes are marginal and fade quickly.
They always seemed fine to me until I started riding my KX500 on the street....
Now I know what they are talking about
As usual I am stealing someone else idea and making it better...

More to come

I ordered a set of 1994 CBR600 F2 front brake calipers for 30.00 including shipping and they were advertised as Used and usable.
When I got them I quickly discovered that the seller has no idea what a good set of calipers is suppose to function like.
The pistons were severely stuck.
After some serious cleaning, 150lbs of air, more scrubbing, and some general maintenance, I finally have a caliper that is worth the effort.
I'm certain a less stubborn person would not have recovered this caliper
Much better..

At this point I'm not doing a full rebuild.
I'm just testing to see if this is possible and how well it works..

As you can see, the caliper guard mounting hole is in the way.... So off it goes..
Once that was out of the way it became apparent that I needed to trim a bit more off the mount here and there for clearance of the caliper and the pads.
No biggie, that's what a Sawsall is for

So here we are.
The mount and caliper are together and this appears to be a viable conversion.

Keep in mind that everything is rough cut at this point so this is not a finished piece until I say it is

Here is the rear wheel adapters that you need to convert the KX450f Rear wheel to fit on a 20mm rear axle.
I picked them up through Warp9 Racing.
I think they retail for about 35 delivered.
Here is what happens if you try to mount everything up without extending the mount.
I cut the mount so that I could add the spacer.
The band saw I used removed about 1.5mm of material.

Here is the KX450F rear wheel mounted on the swingarm with the lower brake mount in place.
Here is a mock up of the set up to determine the spacing I needed for the mount.
Here is a pic of the spacer before I cleaned it up..
The total thickness of the spacer was 16.5mm

So there you are for now.
I need to get it machined and welded.
Then we can plumb it in and take it for a ride and see how it performs...

Thanks Travis for a one day turn around on welding.... U Da Man!!!

Almost ready for a test run..

Ok... I just wasn't happy with the way the pads lined up on the rotor.
Sure, I could have tested it just to see where we were at on it but I couldn't justify it.
So, I removed a wedge to give it better alignment.
Ok Ok... It's a prototype......
But this might end up on someone else bike so I might as well make it a bit better..
On the original attempt I didn't allow for the angle of the mount vs the radius of the rotor.
But this should fix it up nicely.
I didn't get a pic of it but I did mount it up on the bike and it looks much better.
So off it goes to Travis for some lick n stick action

More to come

Ok.. all welded up and ready for another try.
I bled the brake and was all excited... pumped the brake lever... nothing... Pump Pump Pump... Still nothing
Then I notice a puddle of brake fluid on the floor.... Busted SS brake hose....

So here is what we ended up with so far.
KX450F rear wheel
KX450F to KX500 rear axle adapters from Warp 9.
A used 94 CRB600 f2 Right front brake caliper.
KX500 01 rear brake caliper mount.
KX500 93 rear brake hose.
Nothing has been rebuilt.
All I did was disassemble the caliper, clean it, and reassemble it.
Modded the mount to make correct clearance and removed some unnecessary material, then bled and adjusted it.
That's it.
To do this right I should completely rebuild the master cylinder, the caliper, installed new pads (I used the pads that came on the used caliper), installed a new SS brake line, and installed a new rotor.

However, even with all this old used junk the performance is remarkably better..

But how much of the increased braking is from the larger rotor diameter and how much is from the dual piston caliper?
We will have to test it and find out...

I believe this is the final version for the CBR600 caliper..
This is as the bike was tested..