Better batteries and high-torque starters have helped, but starting big inch motors can still be troublesome.
S&S Cycle's compression release system eliminates high compression starting problems. Designed exclusively for S&S cylinder heads, the compression release system consists of a small valve that opens during starting and allows a portion of the cylinder pressure to escape into the exhaust port. The reduced cylinder pressure makes it easier for the starter to turn the engine.
When the engine starts, the valve closes and the engine runs normally, with full compression. With the S&S compression release kit, a stock starter is able to start almost any engine. These compression releases are a good solution for engines using other manufacturer's cams, which do not have built-in compression releases. Fits S&S cylinder heads for big twin.
Electric compression release:
Solenoid operated, this system automatically opens and closes when the starter button is pressed and released. Convenient and simple, this is the best setup for big displacement high compression bikes. Requires S&S die cast rocker covers shown here.
- S&S rocker covers must be used with electric compression releases due to clearance requirements for the solenoids.
- Rocker covers must be removed when installing S&S® compression releases. If lack of frame clearance prevents removal of rocker covers, engine must be removed from frame for compression release installation.
- All S&S heads for 1999-up big twins are machined for S&S compression releases.
- In most cases, S&S compression releases can be installed while the engine is in the frame with the special S&S two-piece socket kit, part #53-0045.
- If cylinder heads are machined for S&S compression releases, but compression releases are not used, special plug part #90-4916 (two required) must be installed to seal the machined hole.
- Stock cylinder heads cannot be machined for S&S compression releases because there is not enough material in critical areas.