The "WLDR" Model Motor develops its maximum Horse Power at 5000-R.P.M. and differs from the "WLD" as follows:

Cylinders are taper ground and fitted with a standard size double slot Lynite pistons. The front piston is beveled off under the lower ring groove and return oil holes drilled.

Large intake ports with same size intake pipe as used on the 74" and 80" motors. The ports, intake pipe and cylinder head dome are polished, and a 1/16"deep channel is cut in the cylinder from the valves to the cylinder bore for free-er intake.

Special intake cam gears - all fitted free.

Valve springs with 25% more tension when the valves are open. The correct length of valve spring with valve on seat is 1-15/16". Check this after the cylinder seats have been refaced and, if more, add washer to obtain the correct length.

An oil groove is cut around the gear shaft 1/16" wide by .012" deep, connecting with the oil hole in the shaft, to insure sufficient oil at maximum R.P.M.

All motors block-tested.

When fitting new piston rings, the gap should be from .004" to .008" when piston is at top center, 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 .004" - Exhaust .006". For races off 100-miles and over adjust intake .006"- and exhaust .008".

Spark timing should be 5/16" to 11/32" 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 before center of the hole.

Circuit Breaker Opening - .022".

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 10 turns. This should require no further setting. At maximum R.P.M. of the motor (5600) one gallon of oil is circulated through the motor every 20-miles. The oil consumption at this speed is approximately one gallon to 250-miles. 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.

The motor is equipped from the factory with No. 4 spark plugs. This plug should be used for ordinary road use. 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".

This model as shipped from the factory is geared as follows; 33-tooth engine, 59-tooth clutch, 16-tooth countershaft, 41-tooth rear wheel which equals a gear ratio of 4,58 to 1.
This is the correct gear ratio for regular road use and for speedway and road racing where maximum speed is required on the straight-aways.
For flat mile dirt tracks a 29-tooth engine sprocket. For ½-mile dirt tracks a 26-tooth engine sprocket.
For speed runs on a perfectly straight flat surface it may be possible to use a 34-tooth engine sprocket to best advantage.
Gearing for T.T. racing and hill-climbing 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 gear in the turns.

For racing it is advisable to equip the machine with an ignition cut-out on the handlebar, to be connected on rear side (timer side) of the spark coil.

Rubber gasoline and oil lines can be supplied for this model, but, due to all of the oil lines being very close to the rear exhaust pipe, for long-distance racing we recommend, instead of using rubber lines, to tape and shellac the entire length of these lines, including the connections.

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 this model at extra cost, is 4 gals. of gas and 1-1/2 gals. of oil.

It is not necessary to "run-in" the "WLDR" motor before it is used for racing as the motor is fitted up free at the factory, but we recommend running the motorcycle at least 500-miles to free up the wheel and transmission bearings before using the motorcycle in competition.

Before entering the motorcycle in long-distance races, always check the valves, piston rings, tappet adjustment, and remove the carbon.