its at 1mm- 1.5mm looks about the size of a creditcard.. i still apply the breaks and it turns off for some reason. Maybe its possibly tuned wrong and ive always played with it like that?.. but it always turns off when i apply the breaks.. also when i always start it i always have to apply gas (i use the idler nob on the controller, i always put it either half way - all the way...)When i go down the street it also doesnt sound like its gargling or anything.