KX500 WR or overdrive transmission, is it possible?

[Sandblaster]

Oops!
12.5% on 1st.
That's a big deal for the woods bike I want to build...

[81cr450]

15 t in 34 t out VS stock 16 in 32 out . 12.5% deeper from what he said

[Sandblaster]

First gear on the kx500 was just too tall for the kind of woods riding I do.
Yes, it was ride-able but wasn't fun.
The low range first is gonna kick butt..
A after market clutch would be a bonus..

[81cr450]

Okay here goes if I'm not clear on anything please get me straightened out as this has taken me quite some time to do & I might be a shade fuzzy on how it all went

These are the parts you'll need from a 1993 klx650r ; inputshaft, 1st gear output gear, 1st gear selector, clutch hub nut ,not pictured. You'll also need all the klx650r gear spacing washers, which arent pictured either.



Then you have to shorten the klx shaft to the k5 length, a little off each end. The bearing surface on the clutch arm end is where you shorten on this side



Just a couple threads off on the other



To where they're the same length like here

[81cr450]

Effing crashing POS

The input shaft requires different bearings with custom carriers to fit it. I cant find my pic with the measurements & honestly if your this deep you really need to calculate it yourself. The clutch side bearing is a TMB205. You can see the carrier here, notice the retainer.



Dont use the stock style washers to retain like this, it does not work.



The clutch arm end uses a hk2012b bearing. I didnt click a pic of the finished product but heres a pic of the trial carrier installed



The other side of the clutch bearing carrier needs to be cup shape as the factory tangs wont catch the smaller tmb205 bearing, so it must be shimmed I used valve spring shims to regain the +1mm, I say +1mm because my carrier is .010 wider than necessary to load it tight against the bearing retainer on the other side. When installing these shims Load everything in the case & check shiftfork allignment, I had to teardown because I didnt check

[81cr450]

With the shift forks & drum all in place loaded in the clutch side case looking at the gear dogs is where the centering takes place. I've got a .015 & a .030 shim in there which ='s the +1mm. One you've installed the shims & gotten the gears centered in neutral, you have your spacer figured, so you can load the spacers, tmb205, clutch hub bearing carrier with washers to see how much you need to thin the hub.



You need exposed thead for the lockwasher engagement with all ^^ that on it



I took even amounts of both sides of the hub





I didnt want to take any more than necessary here for strength obviously. When I final assembled I had to be careful not to push the shaft in or the lock washer would fall off the engagement threads. You also may need to shorten you clutch pushrod or add more washer to the pushrod hub bearing guide. They already have one washer you could order more if needed.

[81cr450]

The 2nd to the last circlip groove , on the clutch arm side, is a snap rings width off of where it should be.



So the gear needed to be cut in a snap ring & 1/2 width so the dogs would engage fully, de-burr with a dremel & fine stone so it slides on the shaft smoothly



Then you take all the washers from the KLX-R trans, which = 1 snap rings width, to push the outer gear where it needs to be



The first gear output & engagement gear are drop in items, nothing special, it does give you 6 shift dogs for 1st instead of 3 like the KX.

[Sandblaster]

Wow 81cr450!!
That is excellent information....
Nobody I know of has done that much work to pull this off.
It is clear and concise..... Great job!
Thanks for posting.

[81cr450]

I rode it today without issue finally. I ended up climbing up through some really rocky uphill stuff & the deeper crawl factor made it less of a fight, more of just a lug it & steer situation. If anybody improves on some of this or can find bearings that dont require carriers please share, I'd like to see this done as an open ended thing that could be improved on from my first run at it

[Sandblaster]

Dutch-K5 Fan

I may have a idea for 5th gear in, only it's for the K5 transmission

kx500 over drive transmission oem-cycle.com 100.png (488.41 KiB) Viewed 12630 times

Here you see 3rd output(26t) laying on top of 5th input(24t) with 5th input gear next to it

kx500 over drive transmission oem-cycle.com 100.png (488.41 KiB) Viewed 12630 times

Side by side, Only third is 64.5mm and 5th is 66.6mm

kx500 over drive transmission oem-cycle.com 102.png (504.78 KiB) Viewed 12630 times

So in stead of having 19/24, you having 19/26. Not the famous Overdrive of 18/26, but it's a start.