1974 - Pajamas are the hot setup when the lining in your leathers starts to go, or if there never was any. You go out riding and sweat a lot into your cotton pj's. Then pull off your leathers and throw them into the corner of the garage; wash the pajamas like you would the rest of your clothing. Your leathers won't stink up nearly as fast and the cotton pj's keep you cooler.
Just don't let anyone see you in pajamas with "pink elephants and blue rabbits" all over them...