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S&S Easy Start Camshafts For Twin Cam Models


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These Easy Start camshafts from S&S are designed for all 1999 to present Twin Cam engine. After installation of these camshaft any Twin Cam engine can easily be started,. Simply because these Easy Start camshafts reduce the cranking compression. This results in easy start of the engine, regardless of displacement or compression ratio. Of course the reduced cranking compression leads to extended starter motor and battery lifetime. The group Easy Start camshafts consist of bolt in cams, available in both chain drive and gear drive versions. All gear drive versions include cams with inner gears. Outer gears should be ordered separately. Proven Performance from S&S, the cams already passed the test for 10.000 starts without even running the battery down.

1. Each of the two exhaust cam lobes are equipped with a spring loaded compression release lobe on the "heal" of the cam at the point where the valve would normally be fully closed.

2. The lobe holds the exhaust valve open slightly at cranking speed. This releases some of the compression, making the engine much easier to crank.

3. Once the engine starts, and rpm increases, the compression release lobe is centrifugally retracted and the engine runs normally, with full compression, and without any loss in performance. This allows a stock starter and battery to start nearly any engine. The centrifugal retraction is fully automatic, so no buttons to push.

Easy Start camshafts are available in the most popular grinds. The design targets were low end torque for touring, peak horsepower for high performance applications and the best possible combination between torque and horsepower, and the 583 is a great over all cam. The proven 585 posted the best results for peak horsepower

•Make sure you select the right cam for the job. Increasing compression ratio and/or displacement beyond the recommended range for each cam will increase cylinder pressure, which makes the engine harder to start and more likely to ping or detonate. Lower compression ratios or displacements will weaken performance at low and mid range RPM.
•A hydraulic press and other professional tools are required to install cams in Twin Cam engines. Additionally, material might be removed from the inner surface of the stock gear cover to install the S&S Gear Drive. The stock crankcase will require modification for S&S 625G, 640G, and 675G cams. S&S recommends that this and related products be installed by a professional mechanic.
•New cam bearings and a new gear cover gasket are required to complete this installation. These parts are provided in the ZPN721950 Camshaft Installation support kit.
•If updating from the stock chain drive system on 1999 thru 2006 models (except 2006 Dyna's), order 1 set Cams with inner gears and 1 set outer cam drive gears, ZPN721941.
•If updating from the stock chain drive system on 2006 Dyna or any 2007 to present Twin Cam model, order 1 set Cams with inner gears and 1 set outer cam drive gears, ZPN750872.
•Due to the characteristics of gear drives, you may experience some valve train noise 

A- 551 GRIND
Best bolt in cam for Touring models with stock or aftermarket slip-on mufflers. Compression 9.0 to 10.0:1. For low end torque improvement from idle to 4000 rpm.

Low end torque and midrange improvement for all models with compression ratio up to 10.0:1.

Best over-all bolt in cam for the Softail and Dyna models with stock or aftermarket slip-on mufflers. Provides strong low end and horsepower improvement from 1500 to 5000 rpm.

Optimized for Softail and Dyna models with slip-on mufflers and high flow air filter. Compression between 9.0 and 10.5:1. Great results from 3000 to 6000 rpm.

Designed for engines of 95 cubic inches or more with compression ratio between 10.5 and 10.75:1.

Designed for engines of 95 cubic inches or more with compression ratio between 10.5 and 11.5:1. This is the grind is installed by S&S in their 124 cubic inches engines.

Designed for engines of 120 cubic inches or more with compression ratio above 11.0:1.

  Valve Timing   Valve Duration   Valve Lift Centreline   Lift@TDC  
Cam Open/Close                
  Intake Exhaust Intake  Exhaust   Intake Exhaust Intake Exhaust
551 15/20 39/18 215 237 .551" 92.5 100.5 .163" .179"
570 20/40 55/20 240 255 .570" 100 107.5 .187" .179"
583 8/15 60/22 204 262 .583" 92.5 109 .131" .199"
585 20/45 60/20 245 260 .585" 102.5 110 .186" .179"d
625 20/55 60/20 255 260 .625" 107.5 110 .189" .184"
640 25/60 65/25 265 270 .640" 107.5 110 .228" .214"
675 25/64 70/25 269 275 .675"` 109.5 112.5 .235" .205"

Additional information

Weight 1.00 kg

A, B, C, D, E, F, G

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The products listed below are what we currently stock; if you have seen a similar product, contact us, as we may be able to source it for you.