Got the bike from a friend yesterday, first ride I noticed a almost constant miss. It's been sitting for about 2 years, and had old gas in it. He changed the oil, cleaned the gas tank, and put a new battery in it before selling it to me. I plan on changing the oil again after a few miles to make sure it's clean, changing the air filter, and plugs. He told me he thought it had to be re-mapped after changing the spark plugs. Is there any truth to that, and is there anything else I should do while I have it taken apart? Thanks in advance, James.