Posts
2397
Joined
3/11/2013
Location
Tacoma, WA, USA
Edited Date/Time
12/23/2025 1:09pm
What is the hot setup for these old bikes?
Most important, what's the sag and fork height setting that makes a good starting point?
I've read old threads, magazines, etc saying that aftermarket linkage dog-bones are a big improvement in cornering. I'm seeing the 132.5mm length everywhere I look, so I plan to try a set of those.
I am building a 1990 model with a set of modern forks.
I'd love to hear your experience if you've owned and raced one of these old green machines.
*edit: December 23, 2025
Here's a build thread from a few years ago for my completed KX500.
https://www.vitalmx.com/forums/Bike-Builds,46/1990-KX500-Classic-Looks-Modern-Handling,1394778
*edit
2014 YZ250F KYB forks.
Emig Racing lower triple clamp with custom Luxon Engineering upper triple clamp.
Emig Racing dog bones.
Frame and subframe gussets added throughout, plus mounts to accept KX450 foot pegs.
2 piece clutch cover mod.
Moto Stuff 280mm front rotor.
Guts Racing +1" firm seat foam.
The list goes on and on...
I ride a lot of sand, prefer the 06-08 KX450 clamp with more offset. I don't go less than +5mm fork height and 120mm on sag.
Enjoy and don't forget to short shift!
OEM for the 500 was 25mm plus a 30mm fork lug offset.
The 48mm KYB Yamaha forks are 32mm offset, so a 23mm clamp would bring you to stock KX500 spec.
I machined my own 7075 clamps for some Yamaha forks with a 22mm offset. That gives me 54mm offset, one millimeter less than stock. Initially I'll be running the same valving as my YZ250 and a 0.49kg/mm spring rate.
I'm planning to make a set of dog-bones to try next week in the 132.5mm length (same as the Emig parts)
Adam43, is the 06-08 a 23mm offset? I believe all those KX-F forks were a 33mm lug offset.
If I'm correct, that gives you 56mm total which is +1mm from the stock KX500 spec. I'll write down 120mm as a starting point for sand.
nytsmaC, Solid advice on the brakes, that OEM Kawi front brake was junk. I will be running a 270mm Galfer rotor on a YZ wheel with a Honda CRF-450R front brake assembly.
The Shop
Free shipping: VITALMX
DeCal Works Huge Plastic Inventory of UFO and Polisport kits.
Luxon 4-Post Bar Mounts
$189.95 - $239.95
I have the bottom end done and I'm working on the top-end tonight.
With any luck I'll get this thing out to a local track called Ward Creek on the 22nd for a little test-n-tune.
A buddy suggested 13:50 or 13:49 gearing.
What are you fellas running for medium terrain tracks and for hard-pack?
The stock gearing was 14:47 for that year, I think maybe he got confused on the front sprocket size.
Can't remember the triple clamp offset, but it was what Emig Racing recommended.
Here’s my old girl.
Eventually I'd like to build a shock with a high speed adjuster. The compression adjuster in these old KYB shocks changes both low and high speed compression at the same time.
Looks like the start of a nice build cwtoyota
Anyone know if any other source is making triple clamp stems to fit ‘19+ KX450 XTrig or Luxon clamps now that Gary Emig passed (RIP) and Emig Racing is permanently closed?
The soft forks springs of the late 80s/90s were what let them turn, I used 23# springs in my 88 (and I think my 92 as well), that's roughly a .41 kg/mm. I think modern, stiffer forks are what’s making the rear dog bones so popular. We didn’t know we were running soft suspension, but we were..
I ran 14-45 gearing for moto and GP races, 15-45 for faster desert stuff. 15-45 is good for 100-105 mph. Taller gearing calms down the torque and lets you hang on longer.
Heavy flywheels can be good.
Don’t short shift too much, let it rev a little and use throttle control to stay alive. Too low RPM/heavy throttle will get massive wheelspin when the tire skips off the ground and the thing will surprise you with the direction change it picks when the madly spinning tire starts hooking up.
Do anything possible to toughen up your hands.
The terror of a head shaking CR500 at speed cannot be overstated.. choppy sweeping turns in the upper gears would send you to the ER, or a Kawasaki dealership, depending on the outcome.
I think the modern steering stabilizer was invented for CR500s. God knows how much they needed one.
I built up this bike and created a thread in the bike builds section a few years ago.
Here's a link if you're interested:
https://www.vitalmx.com/forums/Bike-Builds,46/1990-KX500-Classic-Looks-Modern-Handling,1394778
The forks and clamps pictured above are on the bike and working well with 0.48kg/mm springs.
I kept the standard linkage and initially tested the stock shock with a 5.5kg/mm shock spring, but the valving was way too soft.
A few years ago, I built a shock with a KYB high speed compression adjuster and I firmed up the valving.
That shock is 1.5mm shorter than stock to bring the rear of the bike down a bit.
I added a link to the chain to move the axle to the rear of the adjustment range.
This bike is incredibly neutral and very comfortable to ride.
It turns in intuitively and rolls through a corner the way modern bikes like my 2024 KX450 and my 2023 MC350F do.
Weight is within one pound of both my YZ250 and MC350F, but you do feel that huge crankshaft, piston and cylinder the way you do on a 450F.
You just ride it in a calm way and the lap times are essentially the same as my other, more modern bikes.
I'm running 14:49 sprockets.
I'm 165lbs and the bike does equally well on dirt or grate starts when I've raced it at Washougal.
Pit Row
I don't know of anyone making those stems, but it's not out of the realm of possibility that I'd make a handful of them for the summer.
Shortly after I built my KX500, a buddy tore down his dad's old bike and did all of the same chassis mods I've done to mine including my foot-peg mounts, shorter shock with HSC and a KYB 48mm AOS swap. He's a machinist too, so I gave him some measurements and he machined his own stem from 6061-T6 solid round bar. He has KX250F clamps with YZ450F forks and his bike handles similar to mine.
I still have the programs for the KX500 stem nuts and I could create some programs to make conversion stems on the turning center pretty quickly.
I've also considered making up a batch of the peg mounts for guys who want to do some welding.
I remember that thread, you did a great job on that KX!
Along with that larger front disc, get some Galfer R rated brake pads if they make ones that will fit the caliper model you plan to use.
I prefer the OEM Honda pads. I have been running the same setup on a few other bikes for about ten years.
CWtoyota, I just measured the stock triple clamp offset on 2 different sets of KX500 triple clamps, one set was from a 1998, the other from a 2003. Both measured 22mm offset. Did you measure yours to get 25mm?
I measured everything carefully and spent a lot of time making sure my parts would work as intended.
You have to consider the total offset from stem to axle. That includes the fork lugs, too.
The forks changed from my 1990 model (first year of inverted forks, 41mm) a few times until the last few years were on 46mm KYBs.
Stock 1990 KX500 forks have a 30mm lug offset. The Yamaha forks I installed have 32mm lug offset.
My total offset is 54mm while the stock setup was 55mm on my 1990 model.
I have not measured the offset on a set of Kawasaki KYB 46mm forks from those later KX500 years. I assume it is 33mm.
I am pretty sure all the later model KX stuff with 48mm KYB has 33mm lug offset, so I'd imagine the 46mm forks are the same.
With a 33mm lug, your 22mm clamps would yield a 55mm total offset, the same as my stock 1990 configuration.
I've been playing hell trying to find a set of billet triple clamps for this 2004 kx500 build I dubbed the nickname "the terrifier". It's one of my personal bike builds and actually building it in memory and honor of Cameron Niemela (prymemx).
Anyways I'm wanting to run 2012 kx450f forks, basically the same as the popular kyb sss forks on the yz.
I heard Gary emig passed away who made custom stems to press into modern clamps, same with applied racing the owner also made custom stems but passed away.
Mcs moto in Australia was supposedly running a batch of kx500 clamps but haven't heard much from them, as well as a buddy of mine who has a kx500 build and asked about their batch of kx500 clamps. I tried contacting Jonathan Bell (KXP) and hes out of clamps, kx guru racing team no one wants to get off a set of clamps.
So basically I'm trying to find a set of billet kx500 clamps for this special build of mine, where I can run the more modern forks. Any suggestions or thoughts to making this happen?
When I decided to do a front-end swap I never really shopped around for clamps or a stem. From the start, I knew I wanted to design and mahcine my own parts. It sounds like you know more about the available products and the market for KX500 parts than I do. Since my KX500 was a personal project that I wasn't in a rush to complete, I fit the custom work into my production schedule between customer jobs.
Currently, I'm too busy to set up and manufacture triple clamps and it's unrealistic to think I'll be able to do them in 2026.
It takes time to create production-worthy fixtures and necessary changes to setups and programs.
It's not out of the question for the future, but currently I have some big plans for 2026, so I don't want to make any promises.
I have considered doing a production run of steering stems that are compatible with late model KX-F / KX and YZ-F / YZ triple clamps.
I have a proven design that a local-pro machinist friend is running in his bike with KX250F clamps and Yamaha forks.
That's a product that I can manufacture from material I keep in stock for other products. Also, a stem doesn't require special tooling or special fixtures, so I wouldn't mind making up a handful of them and selling them through my suspension components business.
https://dialedmfg.com
I have some larger wholesale orders in the shop for non-moto related customers right now...
When I have some free machine time coming up, I'll keep the KX500 stems and stem nuts in mind for spring or summer of 2026.
I just used 2019 crf450r clamps to install a 2016 yz450f set of forks onto my 91 kx500 today. Used the conversion bearings all balls racing sells and the crf stem and its uncanny how well it all fit. I'll get some pics Friday when I get back to work
Only part thats honda is the clamps, steering stop will need attention but its gonna be pretty easy to deal with there it looks like. Wheel, spacers, brakes,axle all 2016 yz450f.
That's a slick way to get it done.
Are the Honda clamp bores on the same center distance as the Yamaha stuff?
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