kz650b on diet

So along with a complete restoration I've started putting my 77 650 on a diet. Specifically, the front single disc and caliper have fallen under suspision of being far too heavy for what they do.

My idea is to get the front disc turned down from 7 to 4.5 mm (thickness of my 2004 z750 discs)and perhaps drilled and replace that coldwar looking caliper with a late 90's number-something like this:

cgi.ebay.com/ebaymotors/1995-KAWASAKI-NI...QQrdZ1QQcmdZViewItem

I realize a bracket will have to get made, but there is alot of precedent out there for that.

So the question is, would I be going too far by trimming the rotor that much? Compared to anything modern it appears to be over-enginered by an order of magnitude.

Thanks

She's lost about 19lbs already and as soon as that centre stand goes, along with the modified disc and brake, she'll be like a skinny Kirstie Alley.

zippywhoosh wrote:

...putting my 77 650 on a diet. Specifically, the front single disc and caliper have fallen under suspision of being far too heavy for what they do. My idea is to get the front disc turned down from 7 to 4.5 mm (thickness of my 2004 z750 discs)and perhaps drilled...would I be going too far by trimming the rotor that much? Compared to anything modern it appears to be over-enginered by an order of magnitude.

On 1976 KZ900, the single front disc was 6mm, the dual front disc LTD had 4.5mm discs, and the optional dual front disc factory conversion kit included two 4.5mm discs. Was unaware the 1977 KZ650 single front disc was a brawnier 7mm, but would suspect Ma Kaw engineers had a reason for the thicker single disc.

id be carefull about running a window screen brake rotor,its bad enough doing it with 2 the rotor will get too hot with just one .