Double disc kit - H2C

[Nigel Thorpe]

Hi. So fitting zpower double disc conversion. Everything fitted but no fluid in yet. On both calipers there is a clearance between the moving pads (outers), of around 1mm, whilst the inner fixed pads appear to be hard up against the disc. The wheel will turn but dragging on the back pads. The pistons are back as far as they will go i.e. the caliper is as far inwards towards the wheel as it will go. Trying to move the caliper inwards, to push back the inner pad, off the disc a touch does nothing. So my question is: has anyone had similar or has anyone felt the need for shims/washers between the caliper carrier bracket and the lugs on the fork legs, so as to move the caliper inboard slightly, thus moving the fixed back pads off the disc a touch, then when fluid added the caliper can settle in its normal running position?

[Marmck]

Presume there z1 calipers do you have them on the correct side , proud side should go to fork leg ,just a thought. Does the static pad have a shim behind it?

[malc87]

The Z Power caliper pistons or possibly any reproduction piston are slightly two big when fitted to a genuine H2 caliper?
It makes the pads bind to the disc.
I give mine to Bill Bristow and he machines a small amount from the face of the caliper repro piston .
They are then perfect.
If you using the reproduction z1 Calipers from Z Power I’ve never heard of them having an issue ?
I’ve one on my H2A at the moment which went straight on?

[Nigel Thorpe]

OK, thanks for the response.
It is the complete zpower kit being fitted. So no original H2 calipers involved.
There is no shim behind the static pad, as none supplied with the kit, though there was a thin annular shim behind the old H2 caliper static pad. The piston pads do have shims, as supplied, which look the same as those fitted to the original H2 caliper, that locate over 2 pins on the back of the pad. The new shims fitted to the front side of the piston pad.
I don't see how assembly could go wrong (famous last words), as calipers come all assembled, apart from pads!

[Triple Parts]

The Z Power caliper pistons or possibly any reproduction piston are slightly two big when fitted to a genuine H2 caliper?
It makes the pads bind to the disc.

I don't think it it the pistons, I have measured repro and genuine pistons and they are the same depth. More likely the pads are thicker, EBC especially have a lot of meat on them.

[malc87]

Could well be Tony.