I've been futzing with my 380f since I got it. I start it in the garage and it runs great. I get it on the ice and it bogs and craps out for a good 20 min before running better. Well this past weekend I was up on Nippissing and they were doing Speed Runs. I stopped and talked to a few of the guys and asked why they were warming up their new sleds?? Boy did I get strange look. They told me when the weather is so cold, -45 that day, you have to let the two strokes warm up for a good 20 to 30 minutes!!! Holy crap! I never figured that out!!! Well the rest of the weekend I let the 380f warm up a good 25 min and it ran great!!! Hit the track they plowed the day after the event and got it up to 110 kph!!!! I'm never touching those Carbs again!!!! Except to clean of course.