I have a 1974 Honda CB550 bobber, Ive had the bike for 5 years and usually when I put it away for winter it doesnt like to fire up come spring. usually its the spark plugs,battery or fuses but ive replaced all of those. The spark plugs are firing and can smell gas on them, bike has been sitting for about 6 months and was running and riding fine when I parked it. Bike has good compression, good battery and rolls over good, but doesnt even try to start at all. Before I parked it I was getting ready to install a gas tank which I never did, so bike didnt have a gas tank on it, and fuel lines were drained, but plugged. Maybe something to do with carbs?or mayve vapor lock of some kind? any help or advice would be greatly appreciated thanks