Le Mans 3 front brake calipers

[jerryS]

Apparently there  is supposed to be a shim between the fork leg and the brembo caliper to 'properly' align the caliper to the disk. On my bike the shim is maybe 1mm.. So, a couple of questions: first, why is this actually necessary? The caliper is dual piston (one each side), so the caliper should self-centre the pads on the disk, right? Provided the caliper piston has enough travel, it should make no difference. What am I missing?.. The second query is that my le mans 3 (1983) has 1 shim on each bolt on the RH fork and 2 shims per bolt on the LH fork.. I can think of 2 possibilities here... 1. there is some setting up (shimming) process that is needed that I haven't found a reference to, or 2. a previous owner messed up. Can anyone shed some light on this?

[n3303j]

The shims center the slot in the caliper on the disk so that each puck has an equal distance to travel to reach the disk.

There are so many factors effecting the relationship between the disk and the caliper that shimming the caliper is the easiest way to get the disk centered in the caliper body slot.

[guzzisteve]

You need the caliper centered on the disk. Center where seam is on caliper in the center of disk. Shim is to put it there. Many bikes have them missing. This is how they come on all models with those forks & calipers. They didn't make them perfect fit, you shim to get perfect.
Self centering have a swivel pin so it floats, like BMW used. Why? Call the 800 # and ask Guzzi about their manufacturing practices.

You can buy them at hardware store.