From the Gen1 FAQ;
If you are planning on checking the valve clearances yourself (26,600 mile intervals) a service manual such as those from Haynes & Clymer is always recommended but there are a number of points you should be aware of.
- Firstly as partial removal of the AIS system forms part of the process you should plan on using this opportunity to completely remove the AIS, if it hasn't already been junked.
- Secondly if the service manual tells you to remove the carbs as part of the process (as per Mr Haynes) then this isn't necessary.
- Thirdly it isn't necessary to remove the timing cover in order to find TDC as long as the cam lobe is directly opposite the valve bucket you are checking then this is sufficient, putting the bike in gear and rotating the rear wheel will allow you to rotate the cams.
- Lastly the exhaust valve clearances are 0.21mm to 0.30mm some manuals will say that he upper tolerance is 0.25mm, (thanks to forum member Unfazed for this information), the intake clearances are 0.11mm to 0.20mm.