These are brand-new quality products made in America by the famous “Truett & Osborn” company for Harley-Davidson motors. This is exactly what you need as the foundation for your high-performance motor.
    Nothing adds torque like stroker flywheels! Gives you the power for high cruising speed, and better acceleration, also increases compression.
    This is a very reasonable investment - it’s only a small part of your total motor cost, and does more in one step than anything else - more than hot cams, bigger carburetor, etc., although those parts will work even better on your stroker motor.
    This is not a radical, dangerous and short-lived modification, stroker motors have been built for over 60 years. The motor will not explode, overheat, or wear out immediately (the extra piston travel does shorten the time between top end rebuilds slightly, but we’re talking about years, not months).
Installation
    These flywheels use all standard original or aftermarket lower-end components, including your own crank-pin (except UL), connecting rod set, shafts, bearings, etc. No special parts (other than pistons) are required for installation, and no welding or expensive machine work; this means that your project is less expensive.
    45 and UL stroker flywheels (but not other flywheels) include a comprehensive illustrated booklet (over 5,000 words) with diagrams and dimensions to show you how to do this yourself, including lots of useful information to help “talk you through” the process of installing them.
Design and construction
    The flywheel material is far superior to the original factory cast-iron. Every individually crafted flywheel begins as a 80-55-06 ductile (nodular) iron blank, which is then heat-treated to 220-250 BHN. The 80,000 pound tensile strength blanks undergo an exacting 20-step manufacturing process, utilizing both CNC and conventional precision milling and machining. This insures accurate surfaces, legendary reliability, and excellent “truability”, an absolute necessity when setting up high performance motors to blueprint specifications. If properly installed and maintained, they will not wear out, but give many years of trouble-free service.
    Ductile cast-iron is the superior material for flywheels, since its surface provides a better “grip” on the crankpin and shaft tapers than a steel forging to prevent slippage. Cast-iron also damps out internal vibrations better than steel.
    Warning: this is more complex than a normal rebuild, requiring prior experience and other assembly work. Flywheels must be balanced to your components.

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Flywheel lightening by reduced outside diameter
    Weight removal can be done at added cost. This greatly improves throttle response and 1st gear acceleration, at the expense of reduced low-speed lugging ability, idle quality, and slightly harder starting. No, you do not “lose torque”, this is completely fictional. The exact amount removed varies with the flywheel diameter, and the engine type. Sorry, it’s not possible to predict how much effect this will have on a specific engine. Balancing will be more difficult in all cases since the weight removed cannot be radially symmetrical.
    This is the most effective method in terms of reduced inertia per gram of weight removed, but may need your case scrapers built up for oil control. It’s the least expensive method: $30.00 per set.
    To order, add this to the total price. If you prefer a specific diameter, include a note.

1937-48 U, UL, UH, ULH &c., 8-1/4" OD.
Requires 1¼” crank-pin. Also available in TorqueMonster.

79” stock flywheel set; 4-9/32” stroke. Click for details:

84” Stroker flywheel set; 4-1/2”. Click for details:

86” Stroker flywheel set; 4-5/8”. Click for details.

88” Stroker flywheel set; 4-3/4”. Click for details:

92” Stroker flywheel set; 5”. Click for details:

1937-73 45 WL, WLA, G, &c.

Stroker Piston; pair, only for stroker flywheels. Click for details:

1937-73 45 WL, WLA, G, &c. using 45 rods
Note: much lower shipping cost

861cc Stroker flywheel set, 4-7/16” (52.5”). Click for details:

873cc Stroker flywheel set, 4-1/2” (53.3”). Click for details:

897cc Stroker flywheel set, 4-5/8” (54.7”). Click for details:

1937-73 45 WL, WLA, G, &c. using Sportster rods
Note: much lower shipping cost

Replacement WR, &c. flywheel set, 3-13/16" (stock), for Sportster rod set. Click for details:

873cc Stroker Flywheel set, 4-1/2" (53.3") for Sportster rod set. Click for details:

897cc Stroker flywheel set, 4-5/8" (54.7") for Sportster rod set. Click for details:

1957-85 Ironhead & 1986-* Evo Sportster
Note: much lower shipping cost

4-1/2” Stroker flywheel set. Click for details:

4-5/8” Stroker flywheel set. Click for details:

4-3/4” Stroker flywheel set. Click for details:

1941-47 knucklehead & 1948-54 panhead

Also available in TorqueMonster.

74” stock stroke flywheel set; 3-31/32” stroke. Click for details:

80” Stroker flywheel set; 4¼” stroke. Click for details:

84” Stroker flywheel set; 4½” stroke. Click for details:

86” Stroker flywheel set; 4-5/8” stroke. Click for details:

88” Stroker flywheel set; 4-3/4” stroke. Click for details:

1956-65 panhead, 1966-69 generator & 1971-72 alternator (“cone”) shovelheads

Also available in TorqueMonster.

74” stock stroke flywheel set; 3-31/32” stroke. Click for details:

80” Stroker flywheel set; 4¼” stroke. Click for details:

84” Stroker flywheel set; 4½” stroke. Click for details:

86” Stroker flywheel set; 4-5/8” stroke. Click for details:

88” Stroker flywheel set; 4-3/4” stroke. Click for details:

1972-81 alternator (“cone”) shovelhead

Requires the 1981-* shafts and minor small parts. Also available in TorqueMonster.

82” stroker or replacement flywheel set; 4¼” stroke. Click for details:

86” Stroker flywheel set; 4½” stroke. Click for details:

89” Stroker flywheel set; 4-5/8” stroke. Click for details:

91” Stroker flywheel set; 4¾” stroke. Click for details:

1981-88 alternator (“cone”) shovelhead & Evo

Also available in TorqueMonster.

82” Stroker flywheel set or replacement; 4¼” stroke replacement flywheels. Click for details:

86” Stroker flywheel set; 4½” stroke. Click for details:

89” Stroker flywheel set; 4-5/8” stroke. Click for details:

91” Stroker flywheel set; 4¾” stroke. Click for details:

1989-* Evo

Requires the 1981-* shafts and minor small parts. Also available in TorqueMonster.

82” Stroker flywheel set or replacement; 4¼” stroke replacement flywheels. Click for details:

86” Stroker flywheel set; 4½" stroke. Click for details:

89” Stroker flywheel set; 4-5/8" stroke. Click for details:

91” Stroker flywheel set; 4¾" stroke. Click for details: