yah, those are the idle screws for the3 stock carbs when you remove the tors caps. and, that's not the right way to to a plug chop. you get it up to operating temp by ridding around, then stop at a strait stretch and put in new plugs right away. start it, and instantly run it through all the gears, or as many as you can wot, (10seconds minimum) and pull the clutch and kill it and roll/brake to a stop without letting the engine tun over. change the plugs again and go read those ones. the point is to get the reading by only runnung on the mains. if you do a search, you can find the writups on how to do a plug chop, and read.