1. Deep fin cylinders with 1-9/16" diameter intake ports.
2. Deep fin aluminum cylinder heads.
3. Larger intake manifolds.
4. 1-5/16" venturi carburetor.
5. Intake ports, manifold and cylinder head combustion chamber are polished.
6. 1/16" deep channel is cut in de cylinder from the valve seats to the cylinder for bigger gas charge.
7. Special intake and exhaust cam gears; all gears fitted free.
8. 25% stronger valve springs.
9. Motor is block tested, taken down and rechecked.
10. Motor develops approximately 7 H.P. over the WLD motor.
11. Motor peaks at 5500 to 5700 r.p.m. or about 500 more r.p.m. than the WLD


When fitting new piston rings, the gap should be from .004" to .008" and from .002" to .003" loose in grooves.

The flywheel assembly should have from .015" to .018" end play in crank case, and connecting rods from .012" to .015" end play between the flywheels.

When motor is cold, tappet clearance should be: Intake .006"- Exhaust .008"

Spark timing should be 11/32" to 3/8" when fully advanced. For Accurate checking, would suggest removing one of the cylinder heads. When checking the timing through the timing hole in the crank case, the mark on the flywheel should be as shown:

Circuit breaker open .022"
Magneto point should be set to open .015"

The oil pump is set at the factory as follows: The by-pass valve is turned in until the screw pilot strikes the ball check, the backed up 9 to 10 turns. This should require no further setting. However, if necessary, the by-pass adjustment can be changed as follows: For more oil screw the by-pass down and for less oil screw up. For racing only we recommend using Crystal Oilzum. However, the regular Harley-Davidson summer oil is also O.K. to use. Never use Crystal Oilzum for regular road use, as the motor gum up in time.

See Rider's Handbook for adjustment on standard carburetor. (The approximate adjustment on the high speed needle is 1-1/4 turns.) We suggest adjusting low speed needle a little on the rich side for better acceleration.

The motor is equipped from the factory with No. 4 spark plugs. This plug should be used for ordinary road use. For T.T. and track racing use spark plug No. 5. For long-distance racing on speedways and roads where the motor is run at maximum speed most of the time and you do not get a chance to cool by closing the throttle occasionally, we recommend using spark plug Det. 89-32. The spark plug gap should be .022" to .025" for battery and coil ignition, and.020"to .022"for magneto ignition.

Rubber gasoline and oil lines can be supplied for this model. We suggest using these for long-distance racing.

The capacity of the standard gas tanks is 3-1/4 gal, and 1 gal. of oil. The capacity of the special large tank, which can be supplied for the magneto model at extra cost, is 5-1/2 gals. Of gas. The special oil tank under the seat must be used in connection with large gas tank. The capacity of this tank is 1-1/2 gal.

This model as shipped from the factory is geared as follows; 32-tooth engine, 59-tooth clutch, 16-tooth countershaft, 41-tooth rear wheel - which equals a gear ratio of 4,72 to 1.
This is the best gear ratio for regular road use. For speedway and road-racing where maximum speed is required on the straight-aways use a 33-tooth engine sprocket. For flat mile dirt tracks a 29-tooth engine sprocket. For ½-mile dirt tracks a 26-tooth engine sprocket. This of course depends on the condition of the track and it may be necessary to raise or lowe the ratio accordingly.

Gearing for T.T. racing and hillclimbing also varies with the condition of the course and will have to be figured out by the rider. However, a 26-tooth engine sprocket will take care of most T.T. courses by using second and low. For hillclimbing, use a 26-tooth engine sprocket and run in low gear. For transmission with special second and low gear, use a 20-tooth engine sprocket and run in low gear.

Although the motor is fitted free, it is well to run the new motorcycle at least 100 mile s at speeds not exceeding 60 M.P.H. in order to season the cylinders and put a polish on the cylinder walls. Before using for competition, check the valves and rings and remove carbon.

We recommend balancing the front and rear wheels, as a wheel out of balance will set up a vibration which is sometimes blamed on the motor. A wheel can be balanced by wrapping wire solder around the spokes on the light side, then tape and shellac. It is necessary to rebalance the wheels every time the tire has been removed from the rim.