I've put about a thousand miles on my 05 ST1300. I picked up a set of TwoBros pipes that were a little loud so I added the power tips. In 500 miles they already look sooty. I've got a new air filter and getting 44 mpg. One thing it could be is I had to replace the thermostat last week so that may have something to do with it. Just wondering if this is normal or should it burn clean? Thanks