Danny
Cheers for that. Not sure if they are even similar, but there are more 'N' systems on Ebay than there are 'RS' so thought it might be worth a try.
Regarding the carb. Mine, prior to the current strip down due to knackered exhaust stud/rocker box bolts, always ran fine apart from the very occasional stall (usually at the lights when I've smugly filtered on the outside). I'm hoping that if I only clean it externally it should go straight back on.......No! I must admit that it does seem an overly complex bit if kit, given that it is fitted to a small commuter bike. Having checked the official Honda manual, as opposed to the Haynes thing (which I also have), the trouble shooting points to check for running too rich are as follows:
Choke stuck closed
Float valve faulty
Float level too high
Carb air jets clogged
Sticking float
Dirty air cleaner
Hope this helps(?)
Cheers
Boyd