It should run around 900, I have a '83 8820 (not II). Is the belt running all the way out on the large pulley and in on the samller oneIJ Is the sensor reading correctlyIJ There is way to move the shaft out and that will add some space where you can get alittle more room out of the adjuster and push it over 1000-1100. I have not done this but know of someone that did and I was going to look at his machine. The air has been my only problem with the 8820. But 700 max is not right!