Consolidated KX500 Suspension upgrades

[Sandblaster]

There is nothing you can do that is more important to you going faster then upgrading your suspension.
Guys buy a new bike and they get a fancy reed, pipe, muffler, and handle bar tassels.
Sure, they look cool and offer marginal performance gains.
Should I say it again???

There is nothing you can do that is more important to you going faster then upgrading your suspension.

What suspension can I put on my KX500.
In this article I will only concentrate on 88-04 KX500.
The easiest upgrade is to get the correct springs and valving for your weight.
Who do I recommend?
Pro Action
Ohlins
Race Tech.
I'm sure there are others but the reason that I put Pro Action first is bang for the buck.
The valve kits are awesome...
Just ask Sean Collier.

Sean Collier racking up some air miles on Groot.jpg (35.88 KiB) Viewed 18939 times

After comparing to Race Tech to the Pro Action, the Pro Action are just as good for about $200 less.

[Sandblaster]

So what can I put on my KX500?

You can use 06-16 KX450F front forks if you use the 97-04 KX500 triple tree..
You can bolt them right up from at least 1988-04 KX500 frames.
I have not tried the front wheel or front brake yet to see what is usable...
A customer of mine did try the front wheel and brake from his KX500 and says it all works but that you need some different spacer lengths.

KX250F forks
You can also use 04-05 and 13-16 KX250F Forks.
Again, you can bolt them right up from at least 1988-04 KX500 frames.
Some guys are using 06-12 KX250F forks but the tubes are about 1mm smaller in diameter then the KX450F forks.
Most guys just tighten the clamps and call it good.
I recommend that you get some .5mm shim stock and use it between the fork tube and the triples.

Another triple clamp that you can use is the KX450F triples.
However, you will need a Custom Steering stem from Emig Racing.
Motorrad did this and everything bolts up fine but he did complain about the offset of the triples causing steering issues.

Rear shock.
There is nothing you can bolt up except for a Ohlins..
You can unbolt the clevis from a KX500 shock and bolt it right to the 450F or 250F shock.
The issue is, the reservoir tank is in the way and it will hit the exhaust.
After inspecting the KX450F vs KX500 internals there is little difference.
Same bore, same stroke.
If you decide to remove the reservoir from the 450F shock and relocate it, even if you valve it you won't see any real gains over the KX500 Shock.
Sean Collier and Motocross Action Magazine tested our KX500 shock and love it.

[Sandblaster]

Other forks

I have a customer we built a engine for and he is running a 2013 YZ450F fork.
Here is his comment:
For those who have ridden with that SSS fork....its unbelievable when set up right! P L U S H!!
He said the tube went right into the 97-04 KX500 triples.
He is using a YZ wheel and brake.

Generally speaking, the Chrome diameter follows the outside clamping diameters.
IF that is true, the seals for the chrome tube 17D-23145-00-00 fit 2010-2016 YZ250F and YZ450F so it stands to reason that 10-16 would all bolt right up.
However, the only year I have actually measured is the 2013's and... the 2006 YZ450F.
What you need is something close to the following: UPPER 53.8MM - LOWER 58.9MM
The 2006 UPPER 55.82MM - LOWER 59.06
Or, .080" difference between the upper KX500 and the 06 YZ450F forks
The lower is .006" difference.

Here is some info from another YZ fork guy.
Just some info...SSS forks and clamps
All have 59mm lower clamping surface
'06-'09 450f 56mm top
'10- current 450f 54mm top
'06-'12 250f 56mm top
'13-current 250f 54mm top
two strokes 56mm top
Hope this helps anyone planning a fork swap.
I'm installing new '09 450f forks on a '01 500. Needed to machine out the stock KX top clamp to 56mm to fit these forks.
The fork spacing of the KX clamps is slightly narrower than the YZ clamps, so I'll have to fiddle with the wheel spacers a bit. Otherwise it should be a clean set up.
I own a 2016 YZ450FX, so did some measuring and research before I even bought a 500 and learned that the Yamaha stuff is real close. I used a caliper to measure the diameter of both sets of forks, but since it is just a cheap Harbor Freight caliper, I doubt it is exact, but I figure the difference in measurements between the two forks should be pretty close. The top clamping area was on a difference of 0.01 mm, while the lower was 0.3 mm difference. Just used the stock KX triple clamps, and the YZ stuff slid right in, also used the front wheel and brake from the YZ

Rear Shock (He used a KX500 94-04 are the same)
The shock was leaking, so I sent it off to MX Tech for a rebuild. When it came back, I added a Yamaha TI spring and aluminum collars. Curious to get it out and see how it works/feels.

[Sandblaster]

Triple Trees

I bet we all know by now, 97-04 KX500 triples are great.
But what else can you use?

BRP makes a nice after market set.

DH1 also makes some very nice clamps.
In fact, that is what Sean Collier is running on his bike.

Then of course we discussed using a 450F triple with a custom stem from Emig racing.

There is a ugly rumor that you can use some Yamaha triples.... I will be confirming that later
NOPE... YAMAHA TRIPLE CLAMPS WILL NOT FIT

[Sandblaster]

Here is a note regarding the 97-04 KX500 Triple clamps.
This is wrote by Alex Ward KX Guru Racing Member..

The Newer KX 500 clamps do not fit well with the 450 forks. Close but too tight. you could bore the K5 clamps a bit to the specs I have listed or hit Alan Cameron up for a really sweet upgrade to your bike.

Triple clamp mounting hole dimensions
Stock kx 500- 2.128/2.318
Kx 450F- 2.122/2.330
DH1 conversion 2.125/2.331

21369288_10214465992669490_7949503615498072830_n.jpg (61.58 KiB) Viewed 18538 times

[Sandblaster]

12-15-17 update.
I had a forum member send me the following:

"Just built a 2001 Kx500 using a 2008 Yamaha front end.
I used the kx stem and bearings with the yzf clamps. Easy fit."

So, I will be experimenting at some point in the future to verify this combo..

[kyser777]

what is the ohlins rear shock model compatible, In France I saw many kx500 with ohlins shock!
but what is the model, any idea?



thanks

[Sandblaster]

They were specific to the KX500.
They are more prevalent in Europe than in the USA.
They are hard to find.

[Sandblaster]

Here is a nice upgrade to your conversion.

conversion.jpg (129.95 KiB) Viewed 14637 times

Also, Pile-O-K5 posted a link to Allballs conversion bearing and race kits for the triples.
I figured that some of you might like to check it out.


https://www.allballsracing.com/forkconversion