Topic: Rear shock bottom cushion/bushing/bearing not correct fit to swing arm

[DanishZebra]

Hi all,

I purchased replacement rear shock bottom cushions/bushings (40548-268-000) for my K2 swing arm.
The diameter of the bushings is 22mm but my hole diameter measures at ~19.7mm.


Assuming I have a standard swing arm as it matches the CMSL website diagrams.

Is there a special sized bushing that i was supposed to purchase instead? Am I going mad?

Thanks.

[bryanj]

Are you sure the outer steel sleeve has not delaminated from the rubber and stayed in the hole as it looks like bits of rubber are in the hole

[DanishZebra]

Na its completely cleaned out, the black bits are residual powdercoat. They did not tape off the inside of the hole so I have had to file it out (clearly I have to do a better job for when I install the cushion)

[MauiK3]

I recall mine went in pretty hard on my K3. Maybe you still have some powdercoat in there.
Dremel tool with a flap disc?

[pekingduck]

It is an interference fit, meaning you'll need to put it in a press or use a vice with a bushing (or similar).

But 2.3mm is A LOT of difference.  Just to confirm, as bryanj previously asked, when the old bushing was pressed out, the outer sleeve came out with it, right?

The ideal way to enlarge the hole to fit the bushing is with an adjustable hand reamer.  There is another way, but you wouldn't like it.

[CycleRanger]

It is a tight, interference fit and iirc the holes and bushings are tapered slightly so the bushing goes in one way.

[pekingduck]

I don't think the swingarm holes are tapered.  There may be a slight chamfer at best.  You might be thinking of the upper mounts on a shock that have a double-taper to accommodate the hourglass-shaped rubber bushing.

[DanishZebra]

After closer inspection it looks likely that the outer sleeve is still in there, thanks BryanJ for asking the question! I have measured the inside diameter of the outer bushing sleeve and it is a match to the current inside diameter of the hole in the swing arm, so it makes sense.

Tonight I will carefully remove some of the surrounding powdercoat and then remove the sleeve. fingers crossed it goes alright!

Dane

[pekingduck]

Dane, when the sleeves are pressed out, can you verify the inside diameter on the swingarm on both inside and outside.  I searched for any mention of a taper in the forum, but didn't find any. 
Those bushings had been used on almost all Honda swingarms with clevis shocks, and I don't recall them being tapered or the swingarm.

[Alan F.]

Press them out toward the inside, and back in from the inside. The holes are tapered 0.0004" narrower toward the outside. 

That's 1/10th of a millimeter.

http://forums.sohc4.net/index.php/topic,64520.msg2052726.html#msg2052726

[bryanj]

Nope 100th of a mm

[Alan F.]

Yes  .01mm I just can't speak, or type.

[Don R]

 On a similar note, I had to drill my rear footpeg holes because the standard bolts would not go back in. Who knows what happens to these bikes sometimes?

[pekingduck]

So the swingarm is welded together from separate pieces, and the ring in question is simply a piece of cut tubing.  After welding, heat distortion means it likely isn't even round anymore.  The bushing is automatically pressed in on an assembly line with a jig to align it, so no need for any taper.
But  0.0004", or 0.01mm?  Really?   That's 1/7th the thickness of a normal human hair.  Well within any manufacturing tolerances. This is not high-precision aircraft tolerance.

[Gamma]

I didn’t notice a taper. I pressed mine in from the outside

[HondaMan]

I didn’t notice a taper. I pressed mine in from the outside

That's the right direction: they are tapered slightly with the smaller side toward the middle of the swingarm. The SOHC4 arms are all like this: when I press the old ones out, it helps to press them toward the inside because it shears away the old rust and helps to clean up the loes.

...but then, I have a 20-ton press for this task...

[pekingduck]

Of course you would press it in from the outside - how else could you press it in?

[CycleRanger]

Of course you would press it in from the outside - how else could you press it in?

One could use a vice. 

[Medyo Bastos]

Or a c clamp


Sent from my iPhone using Tapatalk

[Don R]

 You could use a quality fine thread bolt, nut and thick washers.

[pekingduck]

All great ways to do it, with no difference if from the inside or outside.  But if you are using a hydraulic press, the obvious way is to push towards the inside when removing or installing.

Kind of like putting your left foot up on a stool to tie your right shoelace.

[DanishZebra]

Hi all,

Update on this. knocked out the outer collar of the original swing arm bushings. New ones went in with a fat mallet.  Swing arm and shocks now installed.

[bryanj]

There is a dance that goes with the i told you so song