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my machinist is worried about breaking the lower casting while pressing out the stem and bearing. any suggestions on how to support the casting outside the bearing, etc.?

I use a piece of tubing 1-3/4" OD with a 3/16" wall thickness (1-3/8" ID) and about 2-1/2" long. I set the lower clamp over the tube and make sure it is centered so the stem can pass through....

You will also need to machine a small amount off the lower part of the KDX stem where it presses through the lower clamp. The KX lower clamp is about 3 mm or so thinner where it presses through. This needs to be done so the bearing will seat all the way down and bottom out on the lower clamp it self.

Ron

Thanks Ron. Forgive my lacking nomenclature, but wouldn't machining the kdx stem like you suggest be the opposite operation of the knurling that others have suggested?

All of the stem swaps that I have done to date have been on 2001 and later KDX's which requires the machining. I have heard of others having to knurl their stems to fit the lower KX T-clamp as they are too small and I think they are earlier KDX models.

I think the earlier models have stems that are the same size as the lower bearing, but the KX and later model KDX have stems that are .006" larger diameter where it is pressed into the T-clamp.

It is this .006" that needs to be machined down to the same size as the bearing area. Because the T-clamp on the KX is not quit as thick as the KDX (about 3 mm), so there is a short amount that sticks through the lower clamp on the KX T-clamp that is too big in diameter to allow the bearing to seat all the way down and sit on the T-clamp it self.

I would think the earlier stems need to be knurled where it presses into the T-clamp, probably about .006" bigger.

Ron

bear with me while I try to recap:

when the kdx stem is pressed into the kx clamp, there will be a gap between the bearing and the clamp, resulting from the lesser thickness (about 3mm) of the new lower clamp. as a result, the seating surface of the stem, below where the bearing used to seat, needs to be machined down to allow the bearing to move down slightly and seat firmly against the clamp. Am I tracking?

This is going to sound ridiculous (probably no more than everything else I say) but which direction does the stem press? We assumed it presses out from the bottom upward.

Also bear in mind that the TT I have is an aftermarket deal, so my thickness might be more or less than what you've dealt with on the stock clamps. Does that sound right to you?

Thanks again for taking the time to talk!

Just ship your clamps and stem to Ron and give him the job, and know that it will 100% be done right without fear of destroying your parts. If you ( a good machinist) have it all in front of you, it should be obvious.

A little heat will help also, my 20 ton press wouldn't press out the stem cold, but a little heat on the lower triple to expand it and help the locktite let go (if there is any in there) made it a lot easier, probably took 10 ton's to get it out, the KX125 stem was much easier to press out of it's lower triple than the kdx was!

I second the send it to Ron - you will need to get the spacer from him anyway for the top triple and if your machinist doesn't know how to support the lower triple to press out the stem, then it doesn't sound like he is the right guy to have working on it.

The stem is pressed out the bottom. This IS a common mistake most machinists make... at least one did for me. This makes your TT useless and dangerous.

Send it to Ron.... He will do it right and not ask you questions about it that you don't know the answers too...

He's already well into the project. has no doubts about machining the spacer, but I had never read anywhere about the stem pressing out the bottom, and couldn't see the circlip.

So the stem pressed about 1/2 inch the wrong direction, taking part of the circlip with it. He was going to press it back the other way then inspect the bore for damage.

The difficulty supporting the lower was due to the bearing still being in place, and two lugs just outside limiting the available space. I read in the sticky recap that the shaft and bearing get pressed out. This was a bit misleading. Once he removed the bearing he had plenty of surface to support against.

Not sure why he didn't start on the KDX clamp though, for the learning curve, since that's the one that can afford to be a paper weight.

Any amount of pressing the wrong way results in damage to the lower tree and makes it unuseable. The aluminum will have stress cracks that are invisable to the naked eye and it will be weakened beond safe use.


I know... this has happened to me and I had to replace the lower tree... fortunately, it was caught before disaster struck.

So the stem pressed about 1/2 inch the wrong direction, taking part of the circlip with it. He was going to press it back the other way then inspect the bore for damage.

Sounds like he has ruined your T-clamp and you should be looking for a new one....

Ron

I'd get a new T clamp too...

well f*$k me. any suggestions for where to shop?

The fantastic eBay!!!!

should I just go with the cheapo stock one, or get something a little nicer? any ideas what year clamps are compatible?

stock is good enough and should be pretty cheap

Not sure how anyone looking at the lower tt could think it pressed from bottom to top? Its just counter-intuitive?