Swing arm mod, old to new idea for feedback

So my machinist is stuck cause his machine is down so my swing arm isn't done. I was thinking of this idea. Could you not cut the pivot tube of a the z swing arm. Weld up the gap from cutting it. Then insert into the new swing arm tube and either let it float on the bearings (if wide enough) or make a couple simple spacers, may be even weld it in?

Thoughts?

That went right over my head! :woohoo:
Can you explain that a little slower? :laugh:

1. take the z swing arm and cut the pivot tube off the rest of it.
2. Weld a block plate on the tube to fill the gap left by cutting the tube portion off.
3. Take tube and insert into the modern swing arm tube by one of the following;
3a. Might get lucky and the z tube will float on the modern swing arm pivot bearings.
3b. Buy bearings that fit on the modern swingarm from a ID diameter to pivot tube OD.
3c. Make a fixed spacer (large washer type) to do the same as 3b but might as well weld it in too.

The reason for exploring this idea is that you can maintain the z pivot bolt and bearings and while it sounds complicated its actually pretty easy.

Anyone have a old swing arm tube to sell to me?

pm kz1006

I've cut the head tube out of old arms and used them to build off of, much easier, cheaper, and better to just build all new. When you weld the old head tube in it warps and won't be the same. My bearing bores are machined only after all the welding is done to insure they are in line.

Les

les holt wrote: I've cut the head tube out of old arms and used them to build off of, much easier, cheaper, and better to just build all new. When you weld the old head tube in it warps and won't be the same. My bearing bores are machined only after all the welding is done to insure they are in line.

Les

Ah ok. But it did get me thinking. Instead of your mushroom cap idea why don't I just get bearing with the ID of the modern pivot tube with ID of the z1 pivot bolt? Then all I need machined is the length of the modern pivot tube.

How about just having bushings with an O.D that fit the I.D of whatever swingarm pivot youre using,then ream the I.D of the bushings to fit the stock kaw pivot bolt sleeve?

wireman wrote: How about just having bushings with an O.D that fit the I.D of whatever swingarm pivot youre using,then ream the I.D of the bushings to fit the stock kaw pivot bolt sleeve?

That's what I said. lol. :woohoo:

Im talking about using bronze bushings in place of needle bearings in swingarm like they used back in the day with the existing pivot tube in whatever swing arm you use though,no need to cut up a swingarm that way.
Bushings got a bad wrap back in the day mostly because nobody ever greased them,its easy enough to have bushings made up the same length as double needle bearing cages would be

Something like these but in whatever O.D and length you need to fit new swingarm

Oh I gotcha. Well I will look at that option if I cant just buy the right bearing.

Thanks man your posts did get me thinking so we ended up doing this which was super easy... Highlights from what's posted in my project thread.