YZ250 and YZ125 Shifters are a good fit on the KX500

[cwtoyota]

Hey fellas, a friend dropped off her 2008 YZ125 last weekend as we plan to do a complete bottom end rebuild here soon.   It's been sitting on the stand in my shop next to my 1990 KX500 and I glanced at her Tusk shifter that I put on maybe five years ago during the last rebuild.

Long story short ("Too Late!")  I have a bunch of YZ's and spare parts, so I grabbed a new shifter off the shelf.   The OEM and Tusk brand shifter for the 2005+ YZ125 and YZ250 is a great match for our later model KX500s.

The YZ shifter works out to about 1/8" longer (about 3 or 4 millimeters) than the stock KX shifter.   The splines are a perfect fit and it times up to where it is level with the top of the OEM KX500 footpeg.    There are a LOT of options out there for the YZ250 and YZ125, so I thought I'd share this info here.

At full up-shift position, the YZ shifter clears the 14 tooth sprocket and wider o-ring chain fine.   A 15 tooth may or may not touch, I don't have one.

[cwtoyota]

Well, I can't seem to attach the photos I have...   It's telling me the attachment folder is full.  Hopefully this imgur link works out instead.

Link:  https://imgur.com/a/98dX8c1

[sandblaster]

Cool.
The kx450f shift levers work great on 94-04 kx500s.
Hammerhead makes levers 5mm, 10mm, 15mm, and 20mm longer than stock.

For older KX500's find a 94-04 shift shaft and install it.

[cwtoyota]

That's good to know too.   Are the shift shafts larger on the later engine?

[sandblaster]

Larger diameter splines.

[cwtoyota]

Thanks!  I'll have a look around and see if anyone has a new old stock shift-shaft on the shelf.

I'd love to get my hands on a couple of older or busted shift shafts to play around with as well.
     I'm a machinist (CNC shop owner) and have a couple neat ideas...

[sandblaster]

Since the shift shafts have been discontinued, I've had the idea to buy kx450 shafts as they are cheap and plentiful and graft the splines onto the kx500 shaft.
Some v-blocks, a couple of clamps, a little tig welding...
Or, it might be easier to simply replace the entire shaft...
I have not compared the total length of both shafts yet..

[cwtoyota]

I like the way you think!  Cutting up new KX450F parts to scavenge the shafts is exactly what I was considering.
I've been thinking about this with the Yamaha 125 and 250 as a durability upgrade; I break shift shafts at about 80 hours on those.

I cut splined shafts all week long here, but these shifters are so small that it is better to roll them than mill or hob them, so the factory 450F shafts may be the best way to go if they're long enough.

The welding fixture has to be splined, or at least include an edge to accurately time the splines.  Of course, a fella could make a custom shaft that was fine tuned half a spline offset from stock if desired.

Making new actuating plates is actually no big deal.   When I get into the engine, or get another shaft in my hands I'll punch a design into CAD and make up a small batch of the plates to try out and figure which year KX450F or YZ450F has the longest shift shaft.

   

[sandblaster]

Sweet!

[zerofear66]

I like the way you think!  Cutting up new KX450F parts to scavenge the shafts is exactly what I was considering.
I've been thinking about this with the Yamaha 125 and 250 as a durability upgrade; I break shift shafts at about 80 hours on those.

I cut splined shafts all week long here, but these shifters are so small that it is better to roll them than mill or hob them, so the factory 450F shafts may be the best way to go if they're long enough.

The welding fixture has to be splined, or at least include an edge to accurately time the splines.  Of course, a fella could make a custom shaft that was fine tuned half a spline offset from stock if desired.

Making new actuating plates is actually no big deal.   When I get into the engine, or get another shaft in my hands I'll punch a design into CAD and make up a small batch of the plates to try out and figure which year KX450F or YZ450F has the longest shift shaft.

   

How about a LONGER clutch arm?

That would BE gold in this forum

[alward25]

Longer clutch arm has been done.

[sandblaster]

And Alward25 can sell you one...

If not, contact Jason Tanner 541-653-5334

[k9Mike]

I think it would be really helpful to create a sticky thread that listed parts that clever folks had replicated to replace parts no longer available from Kawasaki.  As the list from Kawasaki grows, hopefully the list of alternatives will as well.

Also, there's a post on the oem-cycle forum listing discontinued KX parts, but hasn't been updated for a while.  It would be handy to migrate an updated version of that list here as a companion to new aftermarket substitutes. I know it's work to keep such lists updated, but perhaps members could pitch in as well.

Thx!
- Mike

[cwtoyota]

Longer clutch arm has been done.

I'm actually working on one with a unique design.  I'll make a post here when I get one finished.