Harley Twin Cam Leak-down Test

just a quick, down-and-dirty video that shows how I performed a leak-down test on my 2000 Harley bagger that is equipped with a fuel injected Twin Cam engine.

I used a $20 inspection scope that I purchased from Amazon and attached to my phone to determine when the piston was heading toward top-dead-center on the compression stroke as I turned-over the engine by grasping and turning the rear wheel pulley until the piston was near TDC. It doesn't need to be exact.

With a home-grade air compressor set to 100-PSI and a $42 leak-down tester, I was able to perform a leak-down test on both cylinders within about 30 minutes of rolling the bike into the garage.

Most people say you should do this with the engine at operating temp, but many others feel that testing cold is fine. Typically, the results will be a few points better on a hot engine than a cold one.