Shock swap issue

Slow Goat

Slow Goat

Fun Junkie
Tried getting the photo to display to no avail...
https://m.imgur.com/gallery/7E7BGfz

I’m doing a shock swap and the one thing left is to enlarge the I.D. of the bushing* shown from 10.5mm to 12mm.

Looking for a shop in the Bay Area that can mill/drill out the bushing*. It just holds the shock mounting bolt, no bearings/doesn’t turn.

Have already replaced the lower “eye” with a new bushing, 12mm sleeve and oil seals. The upper eye bolt is also 12mm (actually just smaller than 12mm by micrometer measurement).

Appreciate any help.

* the piece is actually a sleeve, see post#3
 
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ST Guy

ST Guy

Well-known member
Don't just drill it out with the size you think it should be. Measure the diameter of the shoulder of the bolt that will be going through it and size it as close as possible. Reamers may be needed. You don't want a sloppy fit. And you'll need to remove the bushing from the shock. In which case, the shock manufacturer or other suspension specialist may have the correct size bushing as a replacement. And use moly paste on the ID of the bushing and shoulder of the bolt when installing it.
 
Slow Goat

Slow Goat

Fun Junkie
My bad on the descriptor; it is actually not a bushing but just a sleeve.

Per Yamaha’s schematic/parts diagram this is not a removable/replaceable part like the lower eye is (true bushing riding on needle bearings). Exploded view shows it as part of the shock body itself. https://www.partzilla.com/catalog/yamaha/motorcycle/2008/yzf-r1-yzfr1xr/rear-suspension

Just need someone with a mill to open it up 1.5mm. The bolt measures (w/micrometer) at just under 12mm.

Revalving, re-springing and changing the lower bushing/sleeve were cake.

Appreciate the advice, tho.
 
Last edited:
ST Guy

ST Guy

Well-known member
To properly open up that bushing or sleeve, it MUST be removed from the shock.

Size the hole as close to the OD of the bolt shoulder going through it. Maybe 0.002" to 0.003" over the bolt shoulder OD at most. A close fit is important. Even closer fit if you can do it. You don't want the bolt banging the bushing to death.

How much wall thickness will you have on the bushing after you open it up? That's important as well. You don't want it so thin that it starts to deform.

And frankly, I'd take the shock and the fastener that you plan to put through it to a suspension specialist and let them deal with it. Won't cost you much and they'll do it right.

Shouldn't there be some large spacers (like fender washers) on either side?
 
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