Upper shock mount post threads bad. What to do?

On my KZ1000 B2, looks like the PO forced a nut with the wrong thread count onto the post. Buggered up the post threads pretty good. I can force the nut back on, but I'm nervous about it coming off at some point.

I was hoping I could replace the post, but it looks like it is welded into a hole in the frame and is not removable.

What would you do?

I guess I'd lay some weld onto the threads and try to recut them with a die.

KZCSI

KZCSI wrote:

I guess I'd lay some weld onto the threads and try to recut them with a die.

KZCSI

Interesting idea. I don't have the skills or equipment to attempt that. Since the post won't come off the bike, do you think this could be done while still mounted to the frame? Wouldn't you need to lathe it back down to "round" before attempting to recut it? Is there another way to do it while still on the frame?

Maybe I can ride down to Bend and you can show me how that's done.

There are 2 ways I would attempt to repair the stud.
1) Purchase the correct thread chasing die, and thread it on backwards (so that the die will cut when you unthread it) then JB weld the end of the stud. Make sure you completely fill in between the thread crests all the way around the stud. When the JB weld has hardened, file down the excess until the thread crests (major diameter) are slightly exposed. Put some thread cutting oil on the stud and then work the thread die back off the stud. The die should cut a near perfect thread as it comes off the stud.
2) Same as 1) except weld the stud end.
There's my 2 cents worth.

Grantl wrote:

There are 2 ways I would attempt to repair the stud.
1) Purchase the correct thread chasing die, and thread it on backwards (so that the die will cut when you unthread it) then JB weld the end of the stud. Make sure you completely fill in between the thread crests all the way around the stud. When the JB weld has hardened, file down the excess until the thread crests (major diameter) are slightly exposed. Put some thread cutting oil on the stud and then work the thread die back off the stud. The die should cut a near perfect thread as it comes off the stud.

Very cool. Now THAT sounds like something I can do. Thanks.

The 750 that I have has the same problem. The PO thought that a car lug nut would make the perfect nut for the upper shock mount. And it did hold the shock on but it was also the wrong thread pitch.

Your most likely going to have to get a die from Snap-On, Mac Tools, or Matco. Sears, Harbor Freight, Autozone, Advanced Auto doesn't carry the right thread pitch. You'll need a 12mm x 1.0mm pitch.

OR I was suggested using a thread file as long as the threads are too boogered up.

Good luck!

Later, Doug

Looks like a good excuse to do a monoshock setupB)

One more method using my highly specialized southern engineering techniques:
Cut the end of the stud off flush to the width of your shock eye bushing. Drill and tap said stud to say, 1/4-20 size, and use a short stainless allen head bolt with a stainless fender washer and some red Loktite to hold it all together.
You could actually drill and tap it to a smaller size than 1/4-20 so as to maintain more wall thickness on the shock stud. All of the load right there is sheer load, so you'd want the wall of the hollowed out stud to be as thick as possible. But it would be crucial for the hole to be drilled absolutely straight for this to work.

I really like the JB-Weld idea. I looked it up and from the specs and their website it does seem to be strong as steel and they say you can tap it etc so it does seem like a good way to repair threads.

It's also gasoline and waterproof so.. if they ever get their clear version done we could coat our tanks with it ;o) (or if you'd like a dark gray flat finish could use the original right now...)

Grantl, Have you ever actually used JB Weld and recut thread on a shock stud? I wouldn't think JB Weld would be strong enough but I could be wrong. If you have done this, it would be a good idea... why not run a die over the stud after applying the JB Weld?

StreetfighterKz: are you sure the pitch is 1.0 on the 12mm die? My memory tells me it is 1.25 pitch... I could well be wrong. I have a die specifically for this purpose and it is up in the shop. You can buy these dies from Maryland Metrics... it IS the correct size/pitch its just that my memory tells me it is 1.25 pitch. I will check and correct if I am wrong which is entirely possible.

Wired you're right, it is 1.25mm. All I know is most of the dies I found are 1.5mm pitch and too course. My bad. :pinch:

Later, Doug

It is indeed 1.25 pitch. I have a thread gauge that I checked it with.

I ordered a M12 x 1.25 die from Snap-on's website. $3.30 INCLUDING UPS GROUND SHIPPING. :blink:

Wow. What a deal. It would cost me more in gas just to drive to the store to buy it. :laugh:

I'm on the road this week, so I have time to wait for it to ship to me. When I get back, I'll give the JB Weld a try and report back.

Riverroad, I actually thought the same idea you had. And I ain't even Southern! I might try that if the JB Weld doesn't work.

Thanks all for your input!