When I bought my 2002 Savage, the previous owner had drilled 4 holes about 3/8" in diameter in the baffles of the stock exhaust pipe.  As all Savages do, mine backfires a fair amount.  Before I start taking it apart, I wanted to post a few questions.

The previous owner has drilled out the air mixture screw, so I assume he adjusted the mixture.  It wouldn't surprise me if the mixture is rich, mainly because I have averaged less than 42 mpg (seems very low to me), and there is black soot around the holes in the baffles that the previous owner drilled.

So, I'm thinking about tinkering with the mixture and running it a little leaner to see how it affects the backfiring and fuel economy.  I've thought that even if the previous owner added a spacer mod (which could reduce backfiring), the holes in the baffles could cause it to backfire from the disrupted back flow.  But, from what I understand, even a spacer mod isn't any sort of guarantee of reduced backfiring with this bike.

Anyone have any thoughts?

Thanks!

I'll make a bet the PO removed the white spacer in the carb which can make the mid range run rich.