Thanks Boatman- Would you say those carb settings apply to sea level to 3000ft? BTW I removed the pre-filter, put the snorkel back on and hard start problem solved. Seems the combination of the pre-filter opening being smaller than the snorkel & and oiled foam restricts enough airflow to requiring jetting to compensate. For now, I'm not going to re-jet, and I think I will leave the snorkel on, and simply ziptie some UNI universal foam over the snorkel opening when I get in super dusty conditions- btw I have 2 new prefilters in the packaging I'd sell $20ea Seems to me that replacing the paper filter and upgrading to the full UNI set up - and running with out the top of the filter box on would produce best performance. When you look at all the hardware the air has to pass by in the airbox before it gets to the paper filter- sure seems that airflow would be less than optimal.