It depends somewhat on your mileage. I would keep to the recommended interval for the first 20,000 miles, then you can extendthe intervals somewhat. I have over 120,000 miles on my 96 ZX-11, and I check them about every 10,000 miles and even then there is seldom any change. Initially the valvesare seating themselves in. As the miles roll on, wear becomes the major factor and this, of course, increases the clearance, which is far less critical.