I've got a 95 Polaris Xplorer 400L that came in locked up. I had the cylinder bored to 0.75 over (it was already at 0.50 over when it came in). While it was down, I rebuilt the carburetor with a new kit since it had set up for several years without running. After putting everything back together, the engine fires and runs for a second, then dies. I haven't been able to figure out why yet, but I was wondering - do you have to resize the carb jets after boring the cylinder? The jets and needles that I am using are the standard jets.


Just wondering if maybe that could be my problem...

 

Simple quick answer. NO
Could be lots of things. Sounds carb related though.
Make sure carb is getting gas. Take the line off and see if gas runs out. If so, I would take a look in the carb.