Hey Araispeed, Do understand that I am relatively new to NSR's myself so I'm no expert. Also my MC28 is a more recent 96 model with only 11,000 kms on the clock, so there are probably minimal carbon deposits etc. clogging up the power valves. I'm sure in my case it was just a case of lack of use though, as I've given it a decent run at least every month or so since I bought it and the hesitation problem has never come up again.

If your MC18 has a lot more miles, and it is a problem with the power valves (and not something else), then it may be that it needs more than a good run (possibly a proper clean) to get the power valves working properly.