So I am getting the pieces together to make my own tester. I had the vacuum/pressure gauge in the tool box, the amazon blood pressure gauge with pump is $9.89 with free shipping so it is on the way here.  I am looking at the fittings, did you just pick up a brass T and a fitting that will thread into the spark plug hole? Do you know what size that is off hand? I appreciate your insight to post this.  It will be a very useful tool as I am pretty sure I have a leak in my '87 zilla , am currently putting my '91 lt250r back together, and needing one to chase the demons on a 2003 lt50! Thanks again.