KX Guru Racing

KX500 WR (Wide Range) or overdrive transmission, is it possible?
Yes it is.
Just think how nice it would be to have a lower 1st and a longer 5th.
With top speeds approaching 120mph that should make just about all hard core mxer's happy.
As the saying goes, "Speed is only a question of money"
Here is an article from kxriders that goes into some detail.
It has comments from the guy that built the kx500 with the current land speed record.
http://www.kxriders.com/forums/index.ph ... 842.0.html

From the members at KXriders I have found that the gears are not available.
You can beg all you want but few members have them and they aren't selling.
Having a set made would be very expensive.
There was some talk of the KLX C and R models and possibly the KLR650's having a higher ratio that might work.
Well, I intend to see what the real deal is and let you know conclusively.

Basically I'm after a higher 5th gear ratio and possibly Lower 1st gear ratio.
I decided to start with the KLR650 and try and put this issue to rest once and for all with a definitive answer.
So far, it's a definite maybe
I started this by using a 90-04 KX500 Transmission and a 87-95 KLR650 Transmission.
The first step I took was to measure the center line distance between both input and output shafts for the KX500 and the KLR650.
They were only .01MM (0.0004") difference which was probably due to my poor measuring so were good to go on that.
The next thing I did was count the teeth on each gear.
As you can see, there is no 5th gear overdrive, only a change of first and second

K5 90-04 KLR 87-95 KLX650C KLX650R
Input shaft 16T 15T 15T 15T
Input 2nd 18T 17T 17T 17T
Input 3rd 22T 22T 22T 22T
Input 4th 22T 22T 22T 22T
Input 5th 24T 24T 24T 24T
Output 1st 32T 34T 34T 34T
Output 2nd 26T 26T 26T 26T
Output 3rd 26T 26T 26T 26T
Output 4th 21T 21T 21T 21T
Output 5th 19T 19T 19T 19T

Here's the deal, the KLR650 gears do slip right on the KX500 shafts.
The only real difference was the dog ears on the gears.
The KX500 uses squared off ears whereas the KLR uses rounded ears.
No problem you could use all the gears from the KLR650 except for first.
I'll get some measurements tomorrow.
I will also install all the KLR gears on the K5 shafts and then attempt to put them into a set of K5 cases and see what happens...

Ok, here's the answer you have all been waiting for.
NO WAY!!!!!
The output 1st on the KLR is larger then the output 1st on the K5 by 2.5mm.
That would mean that you would have to use the KLR shaft which won't work
Sure you could use some of the other gears but you won't gain anything.
Not all is lost.
We have some info on another WRK5 transmission and will be posting our findings as soon as we have more definite information.

***UPDATE***
We are trying several different combinations of gears from KX, KLX, KDX, and KLR.
We may have stumbled on some combos that will work but we are waiting for more info to develop the best choices.
This is a long a tedious process so please be patient

****NEWEST UPDATE ****
We finally received the last piece of the puzzle (3 more transmissions).
We will be working this week to get some usable information so stay tuned

Mike , read this & see what you think. Might give you some ideas.

http://www.thumpertalk.com/topic/902713 ... o-a-01-kx/

I'm having the brain fart of , does the 94 or so kx250 clutch cover fit the k5 case? Does the 250 crank gear fit the K5 crank end. Could we get the upraded/newer clutch & removable clutch cover in one swoop. Thanks to Dave making me a deal on a bike I'm back in on goin forward with this. I'm 90% sure I have the 12% deeper first gear, but if it could go further ...

That was the article I have been looking for forever.
Somehow I lost the address and could not find it.
I'll look into this tomorrow but if I remember right the clutch covers are too small for the K5.
More tomorrow...

Uuuhhhh yeah I'm we todd did. I just checked the K5 clutch cover against my friends 1994 kx250 & it doesnt line up around the powervalve. Most of the bolt holes look like they line up but...

Maybe the article will help some anyway. It looks like the bigger shaft size under the clutch has some potential to up grade to the newer baskets if the ring gear on the basket can be changed to the K5 gear. If I remember right you pulled a shaft from the later klx that has that bigger shaft on the clutch input.

The 93 KLX650R dirt version is still my plan for the 12% 1st though , I gotta get my jug welded some & adjust my port timing before I pull down the bottom end down though.

Bump , I'm playing with my shaft

I'm really close

I'd post pics but I left my Ipod at work

99% sure I'm gonna get there

12.5% on 1st only but hey its some.

Well, if you need some help with parts, let me know as I have some to donate to the cause...
If the shaft work is done correctly you'll have nothing to be embarrassed about

Got bench shifting fingers crossed, tomorrow

Messed up a bearing & got held up with a "lot" of lathe time. Results forthwith even if I chunk cases