Click here to recommend this page to others


Sidewinder kit by S&S; fits Sportster 1986-1990; bare; stroke: 4-5/16 ”; nominal bore: 3-5/8 ”; 89 in³; gross weight: 28.7 kg; GTIN: 4062094638374

200 kph with an Evo-Sportster? No problem with this power package by S&S. Our Sidewinder kits are as complete as our Big Twin kits. Each part which is necessary for installation is supplied (except tools). As with all Big Bore kits the engine cases must be machined to accept the larger bore cylinders. Sidewinder kits for Evo-XL also require the combustion chamber to be enlarged making the compression ratio completely dependent on the engine builder. We do not recommend compression ratios above 10:1 for street bikes.

Each kit contains:

  • 11 mm longer 3 5/8” cylinder with forged pistons
  • complete trued and balanced flywheels
  • motor mount
  • manifold
  • pushrods
  • all gaskets and hardware

... more
Evo Sportster models 1988–up, which are factory equipped with the one-piece flywheel and pinion shaft, require these conversion parts in conjuntion with S&S Sidewinder or Stroker Kits, because S&S flywheels are using the earlier splined pinion shaft bolted to the flywheel. For a complete conversion you require: pinion gear, oil pump drive gear, pinion shaft nut and lockwasher.
These kits contain cylinder which are 11 mm longer than their original counterpart. Installation of these cylinders requires modifications on the rocker boxes and/or the frame tube.
S&S Power Kits

S&S Power Kits

Since the first V-twin rolled out of Milwaukee there were people who thought about increasing the displacement in their search for more horsepower and since 1958 there´s none who does this better than S&S. Stroker flywheel assemblies and big bore cylinders, installed as separate components or in combinations allow to achieve various displacement increases. Depending on your personal needs and preferences choose from different kits for increases up to 116 cubic inches. The performance of S&S components has been proven in thousands of engines on the open highways as well as on the race tracks of the world and the brand name is synonymous for highest quality in material and guaranteed positive horsepower results.
net price* Quantity Available from warehouse Germany? Into shopping cart
in stock
* United States of America: Tax free shipping. Please check your local import fees.

Spare parts:

  • 63-992

    63-992 Gasket by S&S; for Cylinder base; fits Evolution; paper; nominal bore: 3-5/8 ”; 0.020” thick; gross weight: 10 g; GTIN: 4062094639920

  • 63-997

    63-997 Gasket »Firering« by S&S; for Cylinder head; fits Evolution; metal/graphite compound; nominal bore: 3-5/8 ”; 0.0625” thick; gross weight: 20 g; GTIN: ...


  • 57-428

    57-428 Gasket by James Gaskets; for Cylinder base; fits Evolution; rubberized steel with silicone seal; nominal bore: 3-5/8 ”; 0.020” thick; gross weight: 40 g; GTIN: ...

  • 58-243

    58-243 Gasket »MLS« by Cometic Gasket; for Cylinder head; fits Evolution; steel / fluoroelastomer; nominal bore: 3-5/8 ”; 0.040” thick; gross weight: 107 g; GTIN: ...

  • 55-413

    55-413 Gasket »Firering« by James Gaskets; for Cylinder head; fits Evolution; metal/graphite compound / silicone; nominal bore: 3-5/8 ”; 0.045” thick; gross weight: ...

Have any questions?

  • Our sales team will be glad to help out:
    Mondays - Thursdays 08:00-17:00 CET, Fridays 08:00-16:00 CET
    Phone: +49 / 931 250 61 16