Welcome Area OnlyNew Member Welcome Area Only. Be sure to pop in here and introduce yourself & let us know what Harley Davidson you own. Save your bike related questions for the proper area.
The buttons on the cylinder heads are compression releases. I'm guessing your bike has had some pretty extensive work already done to need them. And welcome to the forums!
What makes these releases required? Pistons? Cams? I have no clue.
Also, what do you think about the electric ones so I dont have to reach down onto the heads every time.