For anyone who wonders:
The official Yamaha statement (Service Bulletin M2006-03, for FZ6 and R6, but the part numbers are the same):Use Loctite 620 and torque to 90NM with the new nut and washer...
So I was about right with 638 (choosed because of higher gap filling capabillites). Compared the data sheets and the 620 is better with higher temperatures.
The official Yamaha statement (Service Bulletin M2006-03, for FZ6 and R6, but the part numbers are the same):Use Loctite 620 and torque to 90NM with the new nut and washer...
So I was about right with 638 (choosed because of higher gap filling capabillites). Compared the data sheets and the 620 is better with higher temperatures.