551 cams are bolt-in cams for 1999-'06 engines. Cams that exceed the limits of the stock valve springs require the use of special high lift springs. Most S&S cams have higher lift than stock and are designed to take advantage of the extra flow of ported stock heads or S&S Super Stock® heads. Due to the high lift of these cams, S&S adjustable pushrods are recommended. Not all grinds are available in the chain drive version. To get the best performance from a performance cam installation, a high flow intake and exhaust system is also recommended.
2005-'06 can use stock valve springs while 1999-'04 will need special valve springs.
Designed for engines with 96 to 106 CID and 9:1 to 9:9 compression this is a bolt-in cam set designed for stock or mildly modified touring bikes. 551 cams are not recommended for compression ratios of 10:1 or greater. Greatly improves low-end and midrange torque, strongest from idle-4000rpm.
Quick installation and Easy Start® Cams allow stock starter to start any engine.
Kit contains cams, gearcover gasket, cam bearings, and instructions.
If OES, 509 or 510C cams are used with the stock chain drive system in Twin
Cam 88® engines, it is recommended to use cylinder heads with stock valve
springs or performance valve springs with no more than 160 lb. of seat force.
For more demanding applications, we recommend the S&S gear drive cams.
When using 1999-'06 chain drive cams for lifts over .510", S&S strongly
recommends that the stock chain drive be upgraded to the S&S gear drive
or to the H-D® #25284-08 or #25284-11 hybrid plate. This kit updates the
problematic spring loaded chain tensioners to reliable hydraulic tensioners
and also upgrades the oil pump.
551 cams are not recommended with compression ratio of 10:1 or higher.
S&S can do a special order cam. Contact your S&S Customer Service Representative
for more information.
Not legal for sale or use on CA or EPA pollution controlled motorcycles.