i found a cheaper and easier way to soften old rubber parts. if you look up the chemical reaction that causes rubber to harden, you will read about something along the lines of the silica within the rubber depleting. so one day while i was trying to slid my carbs back on to old hard carb boots, i started to use a silicon based lubricant spray. i noticed the boots getting softer. so now, any time i run across a hard rubber part, i spray it down with Silicon based lubricant and let it sit covered in a container over night. next morning it comes out feeling brand new and it stays that way.
