KDXRIDER.NET

I pressed a 95 kdx stem into a 05 kx triple tree which did need knurling. Once I pressed it in however, I noticed that there will be an 1/4 inch gap between the bottom of the bearing and the triple tree. I machined a spacer to take up the gap. Is this necessary? Any one else experience this?

Joe

Yes, that is quite normal. So normal in fact that Ron Black has a special spacer machined just for this conversion.

Actually I believe Ron turns the stem down

Really?

Yes he turns down the stem and the spacer is for the top.

really?

Hmm, totally different than how he did mine but OK.

I think I was thinking of the other end! DOH! I don't remember him saying he did the bottom like that on mine and honestly can't remember if it sits flush or not. I'll have to take a look.

the lower bearing on the stem is not flush.

really??

the bearing must take a lot of force to press if there is nothing below it to keep it from sliding down. The original set up is pressed to the bottom. Is there any reason why I shouldn't use the spacer?

Joe

Any spacer under the bearing will lower the bottom clamp and make it that much harder to get the ride height correct for the new forks.


Really!

so I have clearification from RBD. The bearing is to be pressed down all the way and spaced on top instead of the bottom for two reasons. The stops may not hit if you space the bottom and, all things constant, the tree would be lower and therefore the forks would be a bit lower.

The spacer that RB sells is meant to go under the top triple clamp not near the lower clamp. The KDX triple clamps are thicker / taller than most KX clamps so due to the difference in triple clamp thickness when the stem is pressed into the clamp the raised portion of the stem that fits to the clamp will protrude above the upper portion of the clamp. When the bearing is then pressed down onto the stem it will come up against the shoulder of the slightly larger diameter of the stem that is meant to be in the triple clamp and as a result it will not go "flush" with the top of the lower triple clamp like it did with the correct clamp / stem set up. That is why there is a gap under the bearing after the stem swap. some people have left it like that and had good results. I took the time to remove the stem and turn down the diameter so the bearing will sit all the way down on the lower triple clamp.

The ride height will be affected if the bearing is not down all the way. It is up to you as to how important that is. From what I have been reading on here most people want the forks up as far as they can get them. Mine are about 3/4" above the top triple and I wouldn't mind if they were up a little more but they would hit the bars.

I mocked everything up this evening and see why you need to space the top. I also saw why you need to turn down the top of the stem for the upper bearing. I went to put the upper bearing on the stem and it wouldn't go down as far as I needed. I just hope that when I press the stem back out to turn it it goes back in as nearly as tight.

Joe

Again, the top? There shouldn't be any turning needed at the top of the stem. Machining should be at the bottom to get the lower bearing seated all the way to the lower triple.

Really!

SS109 wrote:Again, the top? There shouldn't be any turning needed at the top of the stem. Machining should be at the bottom to get the lower bearing seated all the way to the lower triple.

Really!

I haven't heard of anyone having to do that before (machining the top that is, as for the bottom one, i haven't and it worked fine), so I'm with ss109 on that one

The top of the stem does not need to be turned down for the upper bearing. The lower part of the stem needs to be turned down so the lower bearing will go all the way down.

rbates9 wrote:The top of the stem does not need to be turned down for the upper bearing. The lower part of the stem needs to be turned down so the lower bearing will go all the way down.

Sometimes