Rear shocker bolt dilemma.

[blab]

Gazzi shocks, 81 Jota.
I am trying to work out what washers to use to allow the shocker to swing freely.
The upper bolts appear to be a special stepped bolt.
Its a 12mm bolt 75mm long with a 14mm shoulder 22mm long.
The bush in the shock eye is 14mm ID 16mm OD and 20mm long.
Do I need a 12mm washer between the shoulder and frame ?
Without a washer under the head of the bolt the shock bush has 2mm lateral movement.
Do I use a 14mm washer 2mm thick and have the bush tight between washer and frame,or a thinner washer to allow some clearance and allow the bush to rotate on the bolt ?
I noticed with the top bolts removed, one shock swings freely,the other is tight !
Also one top bolt has had 5mm cut off, the longer bolt hits the mudguard if put in that side,very strange.
These bolts were used with a grab rail when I got the bike, meaning that the shoulder got no where near the frame.
Are longer shoulder bolts needed with the grab rail.

 

[Vince]

I went through this a while back. It's not really important on short travel shocks on road bikes but it all helps a bit, really important on long travel twin shock dirtbikes as that pivot moves much more and having it tight restricts this pivoting ability.
The Ohlins on my Husky use spherical bearings with zero drag. I think that's the reason why there is a rubber bush between the shock eye and the bolt to allow any movement. I just found thick washers to pack out the inner to avoid any touching from the shock eye that might cause drag when tightened. Make the top and bottom similar so the shock stays plumb.
No idea about the specific bolts but I would use common sense, I doubt the bolts came with the shock so someone must have made them and gone to some trouble to do what they did. Probably for a good reason. I hear they do need clearance on the chain guard,some guard trimming, does yours.

 

[blab]

The shocks were removed by a suspension shop in Adelaide for new spring fittment,
just not sure if all was replaced as it should be.

 

[jotacorsa]

Some of the shock companies include sleeves to fit the shock eye for different diameter bolts.
The originals are 12mm without a stepped shoulder as you describe.

Very little rotation in the shock bush but a large OD washer on the outside keeps shock on the bike when bush fails.
Not necessary with original grab bar as it fits outside the shock eye.

Mind the top bolts are not so long as to leave divots in the rear fender.

Some of the aftermarket shocks, with larger springs, require spacing the right hand unit outward to clear the chain guard.

If you fit one washer under the head of the bolt then fit through the eye simply stack up washers to the shoulder.
Use the same number of washers between shock eye and swingarm at the lower bolt.