Topic: Question on Kibblewhite bronze swing arm bushes - '76 750F - Too tight ID

[jmardy]

My swing arm collar is in surprising good shape I guess.
Measures exactly .8435"  (21.43mm) on both ends, in several spots.
Kibblewhite bushings are .8425 - .8430.

Should I:
Turn down the collar?
Turn down the inside of the bushings?

I was planning to use HondaMan's directions to cut some spiral grease grooves into [edit] the collar.
Thanks.

[HondaMan]

My swing arm collar is in surprising good shape I guess.
Measures exactly .8435"  (21.43mm) on both ends, in several spots.
Kibblewhite bushings are .8425 - .8430.

Should I:
Turn down the collar?
Turn down the inside of the bushings?

I was planning to use HondaMan's directions to cut some spiral grease grooves into them.
Thanks.

Hone the ID of those bushings. You can do it pretty well with a new 2-stone brake cylinder hone (because the stones will be straight) until you can slide the collar thru it, just barely. (Ideal clearance is 0.0004"-0.0008", less than 1 thousandth inch).

Don't cut the grooves into the bushings: cut the grooves into the swingarm collar as a grease-spreading device, mimicking the older ones from the early 750 and 500/550 bikes..
If your swingarm bolt lacks the grease fittings, the easiest way to "fix" that is to get a used one (eBay) with the fittings, then drill & tap the ends to use SAE fittings (so the grease gun can latch onto it and actually force grease inside it). Then, if your collar is the type with a single circumferential groove thru each of the bearing areas, drill a 1/8" hole thru both sides of the collar in those grooves (and clean the burr inside the collar that rises) so the grease can go from the [new or modified] bolt into the bearing areas.

The issue with the swingarms that have just one grease fitting in the center of the arm is: once the grease dries out inside, it never greases the bearings again until all it pulled apart and [re]cleaned again. And even then, only the inner 1/2 of the collar bearing site gets grease (in the OEM setup) because the clearance on the outer halves of those collars is zero (that's why they are so hard to assemble/disassemble!).

[jmardy]

Great advice !!! Thank you.
I have your book so I know what to do with the collar.
Yes, mine has the single groove and swing arm has the center grease nipple.

I've ordered one of these:


Much appreciated!

[HondaMan]

That'

Great advice !!! Thank you.
I have your book so I know what to do with the collar.
Yes, mine has the single groove and swing arm has the center grease nipple.

I've ordered one of these:


Much appreciated!

That's the one that will work! Long ago I used those (before I got my lathe) to try to "recover" from using aftermarket-made bronze bushings, because they never fit right, out of their package. It's not so much the maker's fault as it is the lack of information about the differences in the bikes: those bushings you have would likely have worked OK if the bike in question was a 1969-1972 CB750 or the CB500K1/2, but almost none of the later ones. Once the collar changed from the excellent design Honda started with to the cost-cutting version found in the later bikes (i.e. 1 grease zerk in the center of the swingarm pivot is the "marker" of these) the bushings changed, but Honda hid that info. Only those of us with micrometers, calipers and machine tools seemed to know about it? In essence, it was a way for the Honda "Kaizen" (change) system to still function, because if you needed to change the bushings in an older bike, the new parts would FIT the older bike if you bought ALL the parts (bushings, collar, seals, and modified the swingarm to have 2 grease zerk in the middle of it), although you'd play the Devil to get them back together again.

[MRieck]

All Kibblewhie parts need honing... bushings, guides etc Honing....NOT reaming.

[jmardy]

Wow! That took a lot of time. I spent a couple of hours, honing the bushings and polishing the collar with 400 grip wet/dry.
Finally, they fit is perfect.
Thanks for the support!

[HondaMan]

Wow! That took a lot of time. I spent a couple of hours, honing the bushings and polishing the collar with 400 grip wet/dry.
Finally, they fit is perfect.
Thanks for the support!

Yes, it does when done right, good job!