S&S, gear drive camshaft kit 640G (IG)

.640" valve lift. IG = gear drive cam set with inner gears installed only.
The gear drive system is in fact a revolutionary design, different and much more reliable, especially in high lift/performance applications, compared with the original equipment manufacturer's (OEM) chain drive design. A gear-driven camshaft is stronger and will not exhibit any of the mechanical problems associated with OEM chain-driven camshafts. The S&S gear drive kit will increase valve timing accuracy and therefore power by eliminating timing chain slack and the clearances of the stock cam gears. The only downside of gear drive is that you may experience a slight increase in mechanical noise; that is why the OEM uses a chain. It has no other mechanical advantage. Since the chain guides and tensioner are eliminated, there is no longer any possibility of these parts failing and damaging other parts of the engine. The S&S gear drive kit reverses the rotation of the rear camshaft, providing additional operating clearance between the cams. As a result, greater valve lift can be achieved with S&S gear-driven camshafts.
Note: With the exception of the 475G and 510G camshafts, adjustable pushrods (such as MCS 503573) are required to compensate for the smaller base circle of these camshafts.
Note: An S&S gear drive installation support kit (MCS 503566) can be ordered separately if required. The kit includes a cam bearing set, retaining ring and gasket.
Note: It may be necessary to remove material from the inner surface of the OEM gear cover before installing the S&S outer drive gears (which are required and available as 503577).
Note: Using camshafts with .625", .635", .640" and .675" lift will require crankcase grinding.
Note: The OEM beehive-style valve springs on Dyna 04-17, Softail 04-17 and Touring 04-16 models accommodate valve lifts of up to .590" and a valve seat force of 160 lb, up to 6200 RPM. Running above 6200 RPM or with lifts greater than .590" will require high-performance valve springs.


Specifications


Brand
S&S


Application
99-06 Twin Cam (Excl. 2006 Dyna) with non-hydraulic chain tensioners (NU)


Sales unit
Par


Material
Steel


Packaging weight
0 kg


HS Code
84099100


Motorcycle family
DYNA, SOFTAIL, TOURING


Original name
S&S, gear drive 640G camshaft set (IG)