KDXRIDER.NET

Yeah. Hard to believe...but I have a question for you KX fork guys.

Regarding fit of the KDX stem into the KX bottom clamp...

I know the term 'knurling' has been used..that it is sometimes required to get a good fit. But...what is the fit to start with?

My KDX stem slips all the way (to the clip stop) easily. I measure about .002" difference between the two...the clamp being the larger of the two.

This is 'normal'? Who else has had the opportunity to fit their KDX stem into the KX clamp? I think most of you guys had the stem pressed out of one and put into the other without being able to check that part?

Ski: I recall you mentioning something said by a mechanical engineer (some kind of injuneer) regarding the fit of these two pieces..that it isn't necessary to have them squeezed together by the force of God..that the circlip on the bottom and the nut on top (under the top clamp) is what is goig to hold things together?

I'm concerned that with the fit as sloppy as it's starting out (.002") it's never going to fit real good. Certainly not with the 20-some thousand pounds of force I've read it takes to get the stem out.

So..what do you folks think? Much ado about nothing? I'm pretty good at that.

Still, some reassurance that I'm not starting this press-fit plan with some under-spec parts would be nice.

Thanks.

Well CC.... mine did not take near that force to get out... he (the machinist) said it popped right out...hardly no force. So, I think that depends on what it takes for yours. The knurling and industrial Loc-Tite should work just fine for yours as it did mine.

The knurling you had done was on the clamp..right? Not the stem.

I don't know how tight the stem I have was in its clamp. I got just the stem from FRP...no clamp attached.

Your reference to 'Industrial Strength' Loctite IS a reference to 'green' Locttie, right?

Thanks summore. Much appreciated.

Yeah...the clamp... The machinist knows what to use... it's their job!
They don't like to be told how to do it and what to use it seems... and every machinist I knows likes to brag about their work... I think you will be in good hands if you get an old pro.

Indeed.....I think that goes w/ any specific trade involving skilled craftsman. Now what I hate is the $6.00/hr guy at the parts store that thinks he knows whats up

"Why do you want xxx jet. You should be running xxx??? Oh, we don't have it in stock anyway..."

"If you don't use belt dressing you'll ruin that new belt..."

My KDX stem fit my KX clamp with out any effort, it dropped right in. I think .002 was about right, maybe tighter, but the stem could spin freely in the clamp. My engineer, (mechanical at a nuclear power plant) said that, with the ring clip on the bottom, the stem to clamp fit was fine as is. The stem's ring clip can easily hold it all together. With the nut on top providing the clampling action against the pressed lower bearing, the stem will not pull through the clamp, no way he said. Besides, the lower bearing is pressed on. Now the lower clamp is sandwiched between the ring clip and the bottom of the lower bearing. It isn't going anywhere. One more thing; the lower stem is connected to the two forks and the forks are also connected to the upper clamp. So, the forks are keeping the spacing for the clamps just as much as the stem is now, maybe more considering the diameter of the fork legs compared to the stem diameter. To prove this, assemble the triple clamps with the stem fitted as you now have it, without a tight fit, and with the lower bearing pressed on to the stem, to the forks and see if you think a pressed stem to lower clamp fit is truely needed here. The stem's strengh is in it's ability not to bend along it's axis, not in it's ability to keep the two clamps seperated a specific distance. That's done with the pressed on lower bearing, not the lower clamp.

I have to believe that because on my Kawasaki voyager, that's what holds my fork caps on and the springs in. The top cap on those forks are not threaded, theres a dimple on the top you push down on with a large phillips type screwdriver until the little ring clip is exposed, then using a dental type tool, pick the clip out of it's groove that it is held into via spring loading, and let up on the screw driver. This ring clip is about half the diameter of the ring clip used on the stem/clamp for the KX setup.

I had my stem knurled anyway. When I took it in to the machinist, he looked at me funny and asked me why. I explained that the stock stem to clamp fit was pressed and I wanted this one to be as well. He shrugged and said o.k. 10 minutes later, and 15 dollars lighter, l left his business. I've ridden my bike probably a thousand miles without any problems.
Knowing what I know now, I would just drill and roll pin the two parts together and be done with it. (Maybe not. 15 bucks was cheap no matter how you look at it.)

I posted in another thread but will repeat here. On "American Chopper" I note that they use a thread joint between the stem and lower clamp. Now that makes sense; just thread on and off the stem from the clamp!!! Any posibility of getting a large helicoil for the clamp and having the stem threaded to match?

From what I understand (which mightn't be much) is that the knurling process (depending on the knurling tool used) can raise the materials surface up to and beyond 0.5mm. The knurling tool rearranges the material making high points and low points. It's the high points that are 0.5mm bigger and are along with Loctite what holds it all snug. I'm sorry if this is vague but I'm tired and can't find the pictures to show what I'm "trying" to say.

From thread... http://kdx.woodsrider.net/viewtopic.php?t=146

That be it... Cheers Vince...

Soooooooooo,,,,, Do you think I should just get the KX clamp drilled for a roll pin ??? And before you laugh at me for mentioning r r rroll pins I don't need to go back to the stock KDX setup nor can I.
Would the knurling be cheap peace of mind ??? I think so... Ideas peeps ??

Thanks for the input. Ski, thanks for the (re)write on the nuculear guy's point of view.

I understand knurling just fine..know what it is and how it's done and such. I didn't expect a .002" gap between the two pieces, though.

BTW...my calipers say there is an approximately .060" diff between the top KX clamp and the KDX stem. That's a bit large.

Inda: re: if you get an old pro

I might not say that to his face (You're OLD!), but the machinist I've taken stuff like this to in the past has been around a good while. It will be interesting to hear his point of view on the parts.

Thanks folks!

Old machinists are the best. They aren't afraid to try stuff because they have the know how and experiance. The old machinist I took my stuff to offered to turn a new stem!!! I can't remember now but it was about $25 or $50 for a new stem.
I still think a threaded stem to clamp is the best way and someday, I might call the machinist up and have him carve one out for me.