The valve only needs to be pluged if you run lots of arm. I ran one with KHK wheels and it would suck the guts out of the transfer valve every 6 months or so untill I pluged it. Can't remenber seeing one sucked on a bike with stock wheels. I replaced one with the bike leaned against a dumpster behind the Albuquerque Hardly dealer in 1970 because they wouldn't let choppers in the shop. Times change!