What Front Brake Piston? 78 GS750

[Benny78]

Hi,
I dismantled the brakes that came on my 78 GS750, these were mixed, as in one caliper had a 40mm internal sleeve, the other a 38mm sleeve. I've purchased another set of calipers. These have pistons 38mm wide x 40mm long with a solid core. Are these the correct pistons or has someone just used Kawasaki items? Does anyone know where to get the correct front brake pistons? the only ones I can see remotely close are on Parts N More, 38mm x 38mm with a hollow core.

[hampshirehog]

38mm is the standard bore. I think the 38mm length is also standard (I can't remember for sure) but if the 40mm pistons fit then you're good to go.

[Benny78]

Thanks, are there any pros/cons to having the hollow brake pistons to those that have a filled in core? Does this affect the braking performance in any way?