That’s a pretty bike. Determining the value of these is difficult and really the best way, as stated before, is eBay sold listings. The exhaust on that bike alone is $2000. If you are looking for a deal, check local auctions or work with someone that doesn’t have a 4 into 4 exhaust. Barn finds are typically not worth your time. I purchased a barn fresh 72 CB750 to build my CR750 and I have literally replaced everything except the frame. You are a few dollars ahead finding one that needs some work but is in generally good condition.