got a 1974 cb550 with sanke 4 into 4 exhaust...was thinking this winter to put a 4 into 1 on my bike, and would love to sell the 4 into 4. they look decent, no rust and a few minor blemishes, chrome in decent shape. what is the market look like for some used exhaust? would like to make a couple bucks, but wanna be fair. any ideas on a dollar value?