You should listen to me. No, seriously, listen to me.
Join Date: Oct 2008
Location: Santa Barbara
Motorcycle: Blue 2006 GSX-R1000
Re: Help to Identify this front M/C
^The service manual indicates that the OEM bore was 15.8915 mm. A 19 mm MC would be 43% stiffer. I'm not familiar with the K1/K2 details but if it's like K5-K8, the OEM configuration is already too stiff. There's a fair chance that a 14 mm MC would move things into the optimum range. That was a common size used by Yamaha. You might be able to find a cheap used MC to see how it feels.