November 16, 1937
SUGGESTIONS FOR PREPARING 1937 & 1938 "WLDR" MODEL MOTORCYCLES FOR LONG-DISTANCE RACING SUCH AS THE 100-MILE RACE AT LANGHORNE, PA. & 200-MILE RACE AT DAYTONA BEACH, FLORIDA
1. Remove headlight, horn, muffler, speedometer, front mudguard, and rear half of rear mudguard. (Some riders make up a short narrow front fender for protection against sand kicked up by the front wheel). It is also a good idea to devise some guard to cover the spark plugs from fine sprays of water and dump sand.
2. Remove and wash out the oil tank and fill with new oil, either Crystal Oilzum or Harley-Davidson Regular Heavy Oil.
3. Be sure chains, connecting links, and link spring clips are in good condition.
4. Add 1/32" to 1/16" washer under chain oilier adjusting screw to insure plenty oil on the front chain.
5. On 1937 models, remove pressure gauge tube and plug hole in crank case to prevent loss of oil due to possible breakage of this tube.
6. Remove all wires to instrument panel and wire ignition direct from the positive battery post to front connection on coil. This should only be connected when motor is running, and must be disconnected when the motor is shut off.
7. Fit an ignition cut-out wire from the horn button to the rear connection on coil.
8. Remove the generator and fit a plate over the hole in the crankcase. The battery must be in good condition and fully charged.
9. Use rubber gas and oil lines, or tape and shellac entire length of the copper gas and oil pipes to eliminate possibility of breakage due to vibration at continuous high speed.
10. Be sure piston ring and valves are in good condition. Check spark timing - this should be 11/32" to 3/8" when fully advanced. Tappet clearance should be - intake .006" and exhaust .008".
11. Use Det #89-32 or Harley-Davidson #5 spark plug.
12. We believe a 33-tooth engine sprocket will give you the best gear ratio for races such as Daytona and Langhorne, but you should also try a 32 and 34-tooth sprocket and determine for yourself which gear gives you the best results. When it becomes necessary to shift to lower gear in the turns, do not shift to high gear until the motor peaks in second gear.
13. Before the race starts, go over the complete motorcycle; check all nuts and bolts to see that they are tight; check oil in transmission; check chains for correct adjustment, and note if the chain oilier is supplying sufficient oil to keep the front chain lubricated.
Have your pit crew organized for maximum efficiency regarding signals, oil and gas filling and for minor adjustments, should this be necessary during the race, as every second the rider is in the pit counts. Tools should be laid out so they are handy to get at, also a set of spare spark plugs in case it is necessary to change during the race. Have gas and oil handy for re-filling at the 100-mile mark. You should also work out a set of signals so the rider has some idea what position he is in, when to come in for fuel re-fill, etc.