Did a little damage to my right fork lower tube (KYB A-Kit, Black DLC) on my '23 YZ250. It's usable for now, but I'm curious as to what parts I would need and what I'm in for when swapping it out for new one.
A new lower tube is easy to source, simple enough... But, what about removing the lug and swapping it over? Torque specs? What other parts should I have on hand? Links to said parts?
As far as my mechanical ability, I've literally done everything else on this bike or my last YZ, except learn how to lace a wheel. Not that a YZ250 is difficult to work on, but I'm not afraid to tackle a job as long as I know I can get the parts fairly easily.
Edit: Did a little research and took a glance at the lug. The set screw actually looks completely clean (hex is clearly visible). Probably a "perk" of it not being an OEM fork. So, probably just going to go ahead and tackle this thing with heat and care when the time comes. Also thinking I need an oil seal that goes into the bottom between the lug and the tube? Thoughts?
It's just 2 o-rings on the bottoming cone. One seals the cone to the lower tube and another on the bottom sealing the cone to the lug.
My biggest take away from doing a fork lug swap was to make sure the threads are cleaned up where the set screw made contact. After I pulled the set screw out I used a small lollipop burr to remove the damaged threads on the tube (small area ~.125" dia). After that apply heat and unscrew.
You need to remove the set screw and clean up the threads before unthreading the tube. A mill works well for this, but you can also just drill through the tube using the set screw hole as a guide since you're replacing the tube anyways. If you don't do this, you risk ruining the lug threads when you remove the old tube.
Once that's done, heat everything up to about 250F, then unscrew the tube. It should come out pretty easily. Let it cool down, clean it all up, install the new tube and bottoming cone with new o-rings and high-strength Loctite (272, 263, etc.). It doesn't need to be crazy tight, just well seated. Then re-install the set screw. Let it all cure and you're done.
Solid info! Thanks.
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