KX Guru Racing

That's right folks, 26T - FITS 86-04 KX500 - 59051-1150 is no longer avalable



If your KX500 is 10-15 years old it's likely that the bronze bushing is worn out....
Almost every KX500 Jason and I have rebuilt over the last 5 years needed a new gear and we use to simply order a new one.

What to do....
If you look closely you can see that this bushing is split.
So, I am looking for a trans gear of the same dimensions ID and OD... The width can be a little wider with no issues...
Just means a little grinding after the bushing is pressed in.

We are also working on a upgrade

OK, we also found a needle bearing that may work but that is for a later project.

In the mean time Jason and I were talking about how to solve this issue and Jason said that he wondered if one of the trans gears had the same size bushing...
Turns out that yes, first gear has a bushing ID and OD that is exactly the same.
The bushing is a little wider but that is no big deal.

Since I have a bad first gear I measured the ID and guess what? It is right on spec for a new bushing for the Idler gear.
So, I pressed out the bushing.

Next, I pressed in the new bushing from the trans into the idler gear.


As you can see, it's a bit wide but a quick trip to the grinder and sander fixes it up nice.
Also, the bushing is now just a little wider then the stock bushing.

After grinding I measured the ID...
It's perfect.

I wondered why the idler gear wears out so much faster then first gear.
Jason and I discussed it and figured there has to be three reasons.
1. The idler gear is narrower and has an even narrower bushing.
2. The idler gear has a lot of side load on it where the trans has a very even load on it.
3. Potentially there is a lack of oil getting to it.

So, I was thinking about this..


Maybe... Maybe not