43mm '91-'95 KX fork swaps made easier - KLX / KDX250 triples

[Chuck78]

Thanks to all the engine & parts specs on http://oem-cycle.com/BikeIdentification.shtml (great eBay used & new parts seller, btw!), I was able to confirm exact dimensions and swap fitment that others had mentioned here in the past, & realized this could really help KDX fork swappers looking to run 91-95 KX125/250 forks.

The 91 KX125/250 triple clamps will swap to the KDX frames, but 92-95 KX125/250 triples will require a stem swap, although those years stem swap may be the exact same press fit diameter as the KDX stem (most '96+ upgrade forks use a steering stem several thousandths of an inch larger, making the KDX stem no longer a press fit, and requiring knurling to increase the o.d. slightly on the stem, + retaining compound.

Well I have now verified that KLX250/300/650 triples through at least 2007 should all be the same clamping diameters as 91-95 KX125/250/500 forks, and I believe from references on this forum, that 91-94 KDX250 triple clamps share these same dimensions. Most 250's use a lighter aluminum steering stem also, for a minor weight savings

So the KLX or KDX250 triples can mount the 91-95 KX125/250/500 forks as a direct bolt-on, and 94-95 are mid valve forks, a bit more advanced progressive damping that helps for higher speed riding and racing.

You'll of course need the KX front wheel as well, as it has a larger diameter 17mm axle which will give you another advantage over the 43mm KLX forks & the stock KDX/KLX 15mm axle in terms of front end rigidity, as well as the external adjustable rebound and compression of KX forks vs KDX/KLX, + the 94-95 having additional compression stacks on the mid valve, for more progressive high speed damping vs previous years with only base valve compression stacks (perfectly fine for casual woods roding, but mid valves help out in hard fast racing use, desert riding, and motocross).

The KX500 triples these years will be a direct bolt-on to the KDX, but 91-95 / 96 / 97-04 KX500 forks and triples are scarce to come by...

96+ KX125/250 use a 20mm front axle, so wheels must come from 90(?) or 91-95.

I hope this helps someone! No stem swap required when going this route!

[KDXGarage]

1991 offset is different than 1992 - 1995 KX125 / KX250. No mix and match on upper and lower clamps.

[Chuck78]

I also believe that 1996 KX500 triple clamps are completely different, & a quick check on Partzilla shows the KX500 lower triple clamp being unique to that year, so at minimum I'd suspect the offset to be different, making it a 96-only upper & lower compatibility.

OEM-Cycle.com 's specs show clamping diameters of every other year before and after, but not '96 KX500, so I'd be cautious to only use a matching pair of triples and fork if finding a 43mm '96 KX500 front end. I don't see why they'd use a different upper tube on a '96, after all, 500cc open class bikes were no longer a competition sanctioned model, and therefore they no longer were getting the cutting edge development that the 125 & 250 2-stroke were. Still, I cannot yet verify clamping diameters.

If anyone could verify the '91-'94 KDX 250 clamping diameters for certain, that would be excellent.

[Chuck78]

I've got some other more modern fork swap tips and links to share as well, 2011-2016+ Showa Twin Chamber SFF 47mm & 48mm forks, but I'll make a separate topic for this. It's quite spendy, but no machining is required with KX Guru Racing billet triple clamps and steering stem...