One test that has been mentioned before for testing the size of your mains is to find a remote straight stretch of road (with no law enforcement). Wind the bike out in 4th or 5th (above 5000 rpm) for a few seconds then back off the throttle a little bit, if the bike seems to increase in speed, your mains are too small (lean). The thought being that you have slightly restricted air flow, compensating for the lean condition for a moment. The opposite is also true.
