Topic: Swing arm collar - what am I looking at?

[Jonm99]

Hi guys,

Trying to service my swing arm with new bushings... However, I don't understand what I am looking at. On the 1977 k7 I expected to find a dust cap, then bushing then collar. What I see is dust cap then collar that crosses the entire distance of the swing arm with no bushings. Am I looking at this correctly? See attached please. And if it is one long collar, can I simply bang it out with a socket from one side to the other?

Thanks
J

[BenelliSEI]

Jon...... the centre sleeve (#9), goes right across and should be free to rotate in plastic bushings (7) shaped like open ended top hats. The metal end caps (#10) should have rubber lip seals inside. In theory, when you tighten the through bolt, (9) becomes fixed in place and the swing arms and bushings (7) rotate slightly. Not the best of a few different designs Honda used in this space!

The cross tube (9) will push out. A press works better that a hammer, our even a long piece of threaded rod. A washer and nut at one end, deep socket spacer at the other? Turn the nut and see if it moves....... once it’s out you’ll likely need to replace the bushings (7). Any looseness here results in lots more at the back of the swing arm. They will shatter so I often go in with a hack saw blade and carefully cut through them a few times so they chip out easily. When finished, pack the space with grease and replace the grease nipple of needed. I usually make my own bushing (7)replacements, check around EBay and the usual suppliers. Parts are specific to K7/8.

[bryanj]

And the shaft usually wears more than the bushes

[BenelliSEI]

Bryan...... good point. They can be cleaned up, and then make adjustments with busing ID (if you make your own)......

[BenelliSEI]

Jon....... spotted the bushings you need on Vintagecb750.com
Check under “new products”.

[Jonm99]

Thanks for the detailed explanation. I used the threaded rod method you suggested and was able, so far, to nudge the collar and bushing a few mm out from the swing arm. I ran out of time but will continue at it with this method until it's out. As per the new bushings, I've actually already ordered a new paîr from Kenosha_kid (ebay), recommended on this forum.

Thanks again!
Jon

[BenelliSEI]

Well done. They can be very frustrating!

[HondaMan]

The clearances and spec you need for making your own bushings are:
Length 1.75"
Inset from outside edge to inner face of bushings when installed: 0.210"
Clearance between inner (steel) collar and bronze bushings: 0.0004"-0.0008" max. after installation (bronze shrinks a bit during install).
Interference fit of bronze bushings to swingarm: 0.0002"-0.0006" max. Any more than this will collapse the bronze during install, making you hone (and hone and hone and hone...) them to let the collar fit afterward.

Use the end caps and felt seals from the K0-K6 bikes to finish the installation.

Also, drill the long center bolt from each end to the center of the installed bushings with a 1/8" drill (I taper this hole using 1/8" at the inner end for 1", then 5/32" to about 1" from the outer ends, then use a #2 drill for the outer 3/4"-1" hole, and thread that 1/4-28 for grease zerks. Then also cross-drill a hole from the inner end of the holes, to let grease out into the inside of the collar. Install SAE-style grease zerks then into the new end holes. In your collar, right in the middle of the groove in the bearing areas, drill a 1/8" hole thru both sides at the least. These combinations of passages will let you create the original K0-K3 style greasing system that actually worked, unlike the one you have now that doesn't. This latter version came into being on the K4 as a cost-cutting measure, and was cheapened further in the F0 and later arms, like yours.

[Jonm99]

Thanks everyone. Got everything out in the end, and while I thought the collar was a pita, those bushings were a nightmare! I ended up chipping away the lip of the bushings and driving it inwards(!) with a pipe until I was able to push both out from the opposite side.

Hondaman - thanks for the detailed tip on the collar upgrade :-)