What's the deal with these things please? What is the cut off point in compression for requiring them to be installed 10+ perhaps? What does manual mean? You have to open them both up before cranking the mo mo over?
Sorry for the simple questions.

 

If you don't have dual plug heads, the heads have to be removed and they have to be drilled and tapped for CR's. Manual ones have a button you push on them before you crank it. When the engine fires up, they close.

 

Yes, if you are running 10/1 or higher compression, it just makes it easier on your starter to run them. The automatic ones open by themselves before cranking but require an electrical harness to the handle bars. The manuals have to be opened by hand. If you are running stock heads, they have to be drilled for them.

 

very helpful once again.

 

Take a look at the S&S manual compression release. One pull on the **** opens the release valves in both cylinder heads.

 

i have the push in type, they are awesome for allowing my motor to get turned over...w hen i do not use them the motor struggles to get over

 

Same here with the push type on HD MCR heads. Way easier to crank when they are pushed in.