U-Joint Grease Fitting

[98valk]

Thanks Gordon, could not find that thread where I asked the same question.

[gordonv]

I think it was attempted, either install or replace the U with a different one that did have it.

This all happened back in 2012' or so, when the u-joint was unavailable. But it's sold as a unit, the u-joint is stacked into the yoke, and is not replaceable.

Check this thread, might have what you want.
http://www.valkyrieforum.com/bbs/index.php/topic,30570.0.html

[pancho]

Ok, so today I received a precision 392 u-joint to take a look at the rebuild-able u_joint trick. I have a manual mill, so I can open up the yokes as required. I pressed out the caps for one side of a Valk u-joint (not an easy job as they were never meant to come apart and you can't just push one side in until the opposite cap comes out, no clearance for that).



What I found is that the caps for the 392 are not an interference fit in our yokes. The caps are .0002 or so smaller than the openings so you can just push them in and out. I seem to remember someone else discovering this and reporting on it. Unless I can figure a way to knurl the inside of the openings, I see no reason to complete this process. There is always bearing grade lock-tite....  any ideas on this?


Couldn't find anything wrong with the Valk u-joint, caps full of grease and seems tight enough, but it did fix a vibration when I replaced it several years ago.

[Avanti]

Can the yokes be bored out and sleeved back to the needed press fit size?

[The emperor has no clothes]

Can the yokes be bored out and sleeved back to the needed press fit size?

If I remember correctly that was done by some back in the day, and they failed pretty quickly.

[3W-lonerider]

Can the yokes be bored out and sleeved back to the needed press fit size?

If I remember correctly that was done by some back in the day, and they failed pretty quickly.

yes. i was one that bought one of those rebuildable u-joints. it failed within 1000 miles.
the wife and i were in oc maryland. bout 250 miles from home when i started feeling a vibration. we made it home but the closer we got to home the worse the vibration got.
once home i jacked up the back and tore everything apart to find that 2 of the u-joint bearing caps had come out of the yokes. after seeing that i never bought another one even though other people were trying to produce them

[pancho]

Hey lonerider, when you found that the "rebuildable" u-joint had come apart, did you notice what method the person who built it had used to secure the caps? Did he machine the inner yokes and use the inner circlips which came off, or did he do something different?

Doing some measurement this morning I found that while there is a couple ten thou difference between the 392 caps and the bores in the yokes (with the caps being smaller), I found the 392 caps were over .002 smaller than the Valkyrie caps... thats a bunch.  Also, the bores in the yokes are somewhat tapered (maybe used a smaller boring bar and head to finish the bores) which might give you a sense that the 392 caps were fit "good enough" when fully seated... they are not and can wobble under load.

Still thinking about this.

[Avanti]

So the u-joint did not fail, the improper method of installation did.

[3W-lonerider]

Hey lonerider, when you found that the "rebuildable" u-joint had come apart, did you notice what method the person who built it had used to secure the caps? Did he machine the inner yokes and use the inner circlips which came off, or did he do something different?

Doing some measurement this morning I found that while there is a couple ten thou difference between the 392 caps and the bores in the yokes (with the caps being smaller), I found the 392 caps were over .002 smaller than the Valkyrie caps... thats a bunch.  Also, the bores in the yokes are somewhat tapered (maybe used a smaller boring bar and head to finish the bores) which might give you a sense that the 392 caps were fit "good enough" when fully seated... they are not and can wobble under load.

Still thinking about this.

the u-joint caps were held in using the circlips. before installing the joint i put it in the vice and used a pipe wrench to check for looseness and couldn't detect any. but apparently there was enough to make it fly apart.