Upper Shock mount question

[Mikep328]

Today, when replacing the shocks, I found that on my bike, the right shock upper mount had a washer on the inside (between the shock and fender area); the left side had a rubber Oring (?) on the inside.  I assumed the washer was correct and the Oring was not but per the Honda parts book, there is no washer (or Oring) shown on the inside that I can see.  Is it correct that there is no washer between the shock and fender on the upper mount or did I miss it in the parts diagram?

To try to be clear, the upper right assembly was, from inside - out: Washer, Shock absorber, washer, nut.  The left was: Oring, shock absorber, washer, nut.

[McCabe-Thiele (Ted)]

I believe that if you have the original rear dampers that the damper rubbers sit against the frame with a washer & domed nut on top to secure them in place.

If you Aftermarket ones you may well have a different arrangement to allow for a different width of top mount bracket. Mine were aftermarket ones I also have the grab/lift  rail on the right side.

When you say replaced did you mean re-fitted what you had?

[Mikep328]

I installed new shocks.

It had aftermarket shocks - don't know what brand - couldn't find any markings - chrome springs, black body, aluminum adjuster of totally different shape/design compared to OEM, 315mm.  Replacement shocks are all chrome, look exactly like OEM, 315mm.  The upper mounting portion of both sets of shocks is the same width but, of course, I have no idea of the width of that part of the original shocks. 

[Oddjob]

A lot of these shocks Mike are made to be fitted to a variety of bikes, those for instance could fit all 4 of the Japanese manufacturers, so they are made to fit the most models, not your specific model. I've found a number that are too narrow on the upper mount, to counter that you need to space it away from the frame, hence the washer and the oring, clearly they didn't have 2 washers the same size.

If someone could measure the width of the original rubber mounts for your model you'll most likely find yours are a lot thinner.

[Trigger]

The original shocks were 22mm. what i have found over the years is the aftermarket rubber bush is not as wide as the original.  You can use washers to pack it out or replace the rubber with an original fitment .


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[Trigger]

I changed a set a couple of weeks ago. OEM Honda on the left, aftermarket on the right 



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[Mikep328]

Wow, quite a difference in the rubber bush length...Great info, thanks guys!  I'll measure the top mount thickness and go from there re any spacers necessary!

[Trigger]

When spacing out aftermarket shocks with washers, make sure that the bottom of the shock is lined up with the swinging arm mount and not forced to the side. This results in leaking shocks very soon. 
If fitting replacement OEM rubbers they just central themselves as the rubber gives .

[Mikep328]

I measured the bushing width on the new shocks - 25mm - so pretty close to the OEM bushing in the photo.  Not sure whether to bother with any spacers at all...

[McCabe-Thiele (Ted)]

As Graham has said might be worth checking the vertical alignment anyway.

I did this by having both  dampers disconnected at the bottom. I fitted the top of the damper & tightened it up then checked if the buttom bracket aligned closely with the swing arm. If it is a long way out you can see the dampers are out of alignment by eye. Getting it right will prevent premature wear or leaks from the dampers as Graham has said.

[Mikep328]

I'll do that, thanks!

[Trigger]

I measured the bushing width on the new shocks - 25mm - so pretty close to the OEM bushing in the photo.  Not sure whether to bother with any spacers at all...

Once the OEM ones are squeezed in they are 40mm. At 25mm the top of the shock will float horizontally 

[Mikep328]

As a follow up, my right side upper mount needed no washer with the new shock to align with the swingarm.  The left side needed an M16 3mm washer on the inside to align. 

[McCabe-Thiele (Ted)]

That is strange 3 mm is quite a bit, is there any side movement in the rear swing arm or does the shock absorber frame  boss look slightly different in any way?

[Mikep328]

There is no side movement whatsoever in the swingarm - very firm; like a new bike.  Maybe new bushings when it was worked on extensively in '18 and '22 though no mention of that in the receipts. 

The mounts look the same to me by eye. 

FWIW, there can be a difference in the alignment depending on tightness of  the upper mounting nut.  I am not aware of a torque setting for those nuts.  The left side would align with out a spacer if the nut is "snug" but not what I'd call tight.  Car shocks are often tightened until the nut/bolt "stops" against the metal sleeve inside the bushing but there is no sleeve in these shocks.