S&S Cycle 635G Gear Drive Camshaft Set

• Comes with camshafts and inner gears, this kit is designed for those who are replacing or upgrading an engine already equipped with S&S Cycle gear drive cams, and will be reusing the existing outer gears

• Installation kit 910-139 is not included but is recommended

• Fuel injection tuning required.

• Pinion shaft run-out must be checked before installing S&S gear drive cams. Gear Drive cams should only be used in engines with pinion shaft runout of no more than .003″

• A hydraulic press and other professional tools are required to install S&S Cycle gear drive cams. Additionally, material must be removed from the inner surface of the stock gearcover.

• The stock crankcase may require clearancing for S&S Cycle .625″, .640″, and .675″ lift cams.

• S&S recommends that gear drive cams be installed by a professional mechanic.

• Due to the inheraent characteristics of gear drives, you may experience more valve train noise with gear driven cams.

• Oversized and undersized gears are available to help achieve correct gear lash.

• S&S Cycle has found that with 160 lb. of valve seat force, theS&S Cycle gear drive cams will perform well up to 6200 rpm. If higher rpm is anticipated, valve springs that provide higher seat force should be used.

• Camshafts 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.

• To get the best performance from a performance cam installation, a high flow intake and exhaust system is also recommended.

• Quick installation and Easy Start Cams allow stock starter to start any engine.

• Kit contains cams, gearcover gasket, cam bearings, and instructions.

• 1999-2004 stock springs will handle camshafts with lift up to 0.510″. If a camshaft with higher lift is installed, high performance valve springs capable of handling a greater lift must be used.

• 2005-up stock valve springs will handle camshafts with lift up to 0.585″. If a camshaft with higher lift is installed, high performance valve springs capable of handling a greater lift must be used. Cams with over 0.585″ of lift will cause interference between the valve spring top collar and the valve seal with stock cylinder heads.

• Installation of S&S chain drive cams requires special tools. Attempting the cam change operation without these tools will be difficult. Damage can result which will not be covered under warranty.

• For lifts over.510″ S&S strongly recommends that the stock chain drive cam be upgraded to the S&S Cycle gear drive or to the H-D part number 25284-08. This kit upgrades the problematic spring loaded chain tensioners to more reliable hydraulic tensioners, and also upgrades the oil pump

• 635 is a high lift cam for modified engines with 106″ or greater displacement and compression ratios between 10.0:1 and 11.0:1. Works well with stock, un-ported heads, but S&S CNC ported heads are recommended. Best power from 3000-6000 rpm. This is not a bolt-in cam set. High-lift springs and clearance checks are required.