Start any engine regardless of displacement or compression ratio with a stock starter
Save your starter and battery; tested for 10,000 starts without running battery down
Allow for easy start by initially reducing crank compression; once the engine starts and RPM increases, the compression release lobe is centrifugally retracted so the engine runs normally with full compression and no loss in performance
All chain-drive cams include an installation kit
All gear-drive cams include a 4-gear set and installation kit
Gear-drive cams are also available with inner gears only for motors already converted to an S&S gear-drive system
Made in the U.S.A.

Performance and Versatility

S&S Cycle Easy Start Cams are designed to provide a significant performance boost for Harley-Davidson Twin Cam motors while eliminating the strain of high-compression starts. Whether you are looking for massive low-end torque for a heavy touring bike or high-RPM horsepower for a stripped-down performance build, these cams offer a bolt-in solution for various displacement levels. Profiles range from optimized touring grinds that pull hard from idle to 4000 RPM, to high-output profiles designed for modified engines reaching up to 6500 RPM.

Optimized options for Touring, Softail, and Dyna applications
Available for both chain-drive and gear-drive configurations
Options available for stock heads or highly modified engines with ported heads and large bore throttle bodies
Provides a broad torque curve and improved output over the entire RPM range

Technical Specifications and Requirements

To ensure peak performance and longevity, please note the following technical requirements for specific applications:

1999-2004 models may require high-lift springs depending on the specific lift profile selected
1999 Twin Cam models will need to use the splined cam drive OEM 25716-99
High-lift profiles (above .585) typically require high-lift springs and may require increased compression and low-restriction intake/exhaust for best results
Installation kits are required for proper setup; chain-drive kits typically include necessary components, while gear-drive versions provide the full 4-gear set

HP103 EZ Start Cam Grind:

Use with stock heads (up to 10.2 compression) and low restriction intake and exhaust
Bolt-in cam for 103” and 106” Big Bore Twin Cam motors
Great for lighter bikes with strong power from 3500-6000 rpm

MR103 EZ Start Cam Grind:

Use with stock heads and low restriction intake and exhaust
Bolt-in cam for 103” Twin Cam motors
Broad torque curve improves output over stock over the entire rpm range

551 EZ Start Cam Grind:

Pulls hard from idle to 4000 rpm
Can be used with stock pushrods, springs and lifters
Optimized for 88"/96"/103" to 106" Touring bikes with slip-on mufflers and 9.0 to 10.0:1 compression
Best bolt-in cam available for most 05-15 Dressers

557 EZ Start Cam Grind:

Bolt-in design
Designed for Tri-Glides and other heavy bikes needing good bottom and mid-range performance

570 EZ Start Cam Grind:

Compression ratios below 10:1
For 88/95/96/103 cubic-inch engines
99-04 models require high-lift springs

583 EZ Start Cam Grind:

99-04 models require high-lift springs
Optimized for use as a great overall cam for Softail and Dyna, but can be used in any Big Twin
Provides strong low-end torque and horsepower you can really feel
Strongest from 1500-5000 rpm in a Softail and Dyna application

585 EZ Start Cam Grind:

Great results from 3000-6000 rpm
99-04 models require high-lift springs
Optimized for 95" to 106" with slip-on mufflers, high-flow air filter and 9.0 to 10.5:1 compression

635 H.O. EZ Start Cam Grind:

RPM range 4000-6500
High-power cam for modified engines, increase compression, high lift springs and large bore throttle body required
For best results, requires ported heads and low restriction intake/exhaust

640 EZ Start Cam Grind:

Strongest from 3,000-6,000 rpm
Compression ratios from 10.5:1 to 11.5:1
For 95/96/103/110 cubic-inch engines
High-lift springs required

Stock Reference	Open	Close	@ .053	Valve Lift
Intake	-02° / 02°	38°/34°	216°/216°	.473
Exhaust	36°	04/04°	220/220°	.473

Country/region

S&S Cycle 910-0481 Black 98" CI Big Bore Cylinder Kit 9.8:1 for 99-06 Harley

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