Triple tree steering shaft threads

javjacob · Post by **javjacob** » 06:54 pm Nov 27 2016

I just realized as I was putting the KX500 triple tree on my KDX that the threads for the upper triple are a bit flattened/smashed. The top 30mm nut will thread on but I don't feel too good about it. Does anyone know the size of the threads and where can I get a die to fix it? No one locally has one that size so I will need to order one online. Kind of a bummer because I was looking forward to getting the front end finished up this weekend.

pumpguy · Post by **pumpguy** » 08:12 pm Nov 27 2016

I can't tell you the exact thread size for your steering stem, but I have some suggestions.

For just a few burrs on the threads, you might try a metric thread file. These are square and have 8 different pitches.

General Tool's # 177-8 metric thread file is an example. Price is like $13.00 and may come in handy whenever you need to clean up metric threads.

A better choice is an adjustable thread restoring tool. These have a thread chaser on the adjustable end and a soft metal (aluminum?) V block on the other end. You snug up the chaser into the threads with the V block on the opposite side for support and rotate the whole tool around the threaded part to clean up the threads. You will need a chaser that has the same pitch as your stem threads.

These are quite pricy but you may be able to rent or borrow one from an automotive machine shop. Nes brand thread restorers are an example.

Before using any of these tools, you will need to determine the pitch of the thread on your steering stem. A thread pitch gauge is the best tool for this job, but if you have some metric bolts lying around, they will serve the purpose. Just find one whose threads mesh with your stem threads. Spark plugs are M1.25 pitch while most of the bolts on your bike are M1 pitch.

javjacob · Post by **javjacob** » 11:03 am Nov 28 2016

The only threading tools I am familiar with are taps and dies. The threads are smashed 3/4 of the way down, only a few threads of the nut are getting solid threads.

javjacob · Post by **javjacob** » 11:26 am Nov 28 2016

I looked up the thread restoring tool but they aren't big enough from the ones I looked up. The thread repair file might work but looks like it would be time consuming which I am fine with if it works.

pumpguy · Post by **pumpguy** » 02:36 pm Nov 28 2016

Another place to look is McMaster Carr. Go to their website and enter THREAD RESTORING TOOLS in the search bar. They show Inch and metric dies as well as other external thread restoring tools.

If you can measure the OD of the threaded area and determine the thread's pitch, you should be able to come up with the required die size.

Kind of pricy either way, but at least they are available, and you may find someone that will lend or rent you the tool you need.

Another source I know of is Tracy Tools in England <www.tracytools.com>. They specialize in these kinds of tools so you might find something there.

doctord23 · Post by **doctord23** » 10:40 pm Nov 28 2016

Get a thread file as was suggested.
These come in handy a lot.

javjacob · Post by **javjacob** » 02:24 am Nov 29 2016

https://www.mcmaster.com/#standard-dies/=158vxi2

Only problem is I have no idea what size I need or how to find out.

https://www.mcmaster.com/#thread-repair-tools/=158wl4u

Would this work?

javjacob · Post by **javjacob** » 02:59 am Nov 29 2016

Here is a pic of the threads...
http://s1253.photobucket.com/user/javja ... sort=1&o=1

Post by **Tyl3r** » 07:59 am Nov 29 2016

To me, it doesn't look like there is enough material there for a thread cutting tool to fix.

pumpguy · Post by **pumpguy** » 10:28 am Nov 29 2016

I agree.

This looks like a machine shop repair is needed. Threaded area would need to be welded over and the threads re-cut, most probably with a single point tool on a lathe.

If going this route, you will need to provide the machine shop with a new nut they can use to determine the thread pitch, and also use as a gauge when cutting the thread. Be sure to ask the shop if they can lathe cut metric threads.

javjacob · Post by **javjacob** » 01:35 pm Nov 29 2016

I was afraid of that. I still have the KDX front end so I have a spare shaft. I don't know if there are any local machine shops that can do it for me or not. I will have to do a search and make some phone calls.

Post by **Tyl3r** » 04:00 pm Nov 29 2016

I would just try replacing the shaft. If you have a press (or a friend with one), it can be changed pretty quickly and easily. Can't be that expensive....

Also, I don't know the likely hood of this with the years you are working with, but maybe you can press out your KDX stem, knurl the portion that gets inserted into the lower clamp, and press it into the KX lower clamp? I know people have done that in the past.

javjacob · Post by **javjacob** » 01:29 pm Nov 30 2016

I talked to the dealership mechanic and he said he should be able to press in the KDX stem. Going to take it to them for them to look at it. I also noticed the Kx500 shaft that is stripped is aluminum, the KDX stem is steel.

javjacob · Post by **javjacob** » 02:55 am Dec 15 2016

Got the Stem replaced with my old KDX stem which is the same as far as I could tell but now I have another problem. There is a gap and I can move the upper triple up and down. Not sure what to do.

Post by **bufftester** » 05:20 am Dec 15 2016

You have to install a spacer underneath the top triple clamp (to account for the differences between the KX and KDX triples). And you will need to shim the upper triple stem hole to account for the KDX stem being slightly smaller in diameter to the KX one. All covered in the Fork Conversions forum on this sight.

Post by **KDXGarage** » 12:56 pm Dec 15 2016

washers

bufftester, KX500 steering stem ID is the same as KDX, so no shimming required.

javjacob · Post by **javjacob** » 01:01 pm Dec 15 2016

Thanks for the info! A washer will be a easy fix. The upper triple went on the shaft nice and tight.

javjacob · Post by **javjacob** » 02:18 pm Dec 15 2016

Ok now I see what you mean. I put my extra nut on as a "washer" and see that the upper triple is no longer snug. Also if I use the other nut as a spacer I will need to mill it down to get the correct height. Is that what the RB spacer fixes? If so I will just buy one from RB.

Post by **KDXGarage** » 07:22 pm Dec 15 2016

RB spacer takes up space below and in the inside of the ID

Post by **bufftester** » 07:32 pm Dec 15 2016

Yeah, if the KDX shaft is the same diameter as the KX500 then you don't want the RB spacer. Search your local hardware store for some large diameter fender washers.

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