1901-1953 Indian Motorcycle – Parts – Accessories

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  5. 66 – Model 436 Changes/Indian Scouts with Daytona-Savannah Motors

MODEL 436 CHANGES


There are two changes which should be made on all Model 436 motors to improve performance, flexibility and gas economy. These changes are :

  1. Installing an inlet manifold cover
  2. Changing the carburetor float and valve seat assembly

Instructions for Installing the Inlet Manifold Saver

The purpose of the inlet manifold cover is to raise the temperature of the manifold and obtain better
vaporization of gasses resulting in smoother engine operation throughout the throttle range.

  1. Disconnect brake rod at pedal, gasoline line at carburetor, and carburetor control casing
    including control casing clips and toggle.
  2. Remove exhaust manifold shield and carburetor choke control assembly.
  3. Disconnect spark plug cables, unfasten cable protector tube clip and push tube (up) out of way.
  4. Remove carburetor and inlet manifold assembly.
  5. Change carburetor float valve seat if necessary – see instructions.
  6. File off boss on LOWER FRONT of inlet manifold (where the throttle control casing clip attaches).
  7. File off choke control wire casing boss. Note – On early 436 Models, this boss has a plain drilled hole, on later models a tapped hole.
  8. Fold the manifold cover rear clip over the inlet manifold between No. 3 and No . 4 risers. Keep clip nut on outside front and center. Bind clip to manifold at the back with screw provided.
  9. Assemble manifold and carburetor to engine.
  10. Attach cover to manifold, closed end at the front and curved portion on top . On models having toggle lever to operate carburetor throttle, use toggle lever screw for cover front support, and put washer provided between
    toggle lever and nut. On later models, use 1/4-20 screw provided . On all models, attach rear of cover to special clip around manifold with 1/4-20 screw provided.
  11. Re-assemble carburetor control, gas line, exhaust manifold shield and brake rod with the following changes:-
    Attach manifold control casing clip under spark plug protector tube clip (applies to early models) or attach control casing clip with screw to tapped hole in manifold cover (applies to later models). Run choke control casing OUTSIDE
    plug cable protector tube.

Instructions for changing Carburetor Float Valve and Seat Assembly. (For motor numbers up to DCF-546. Motors above this number have the new valve seat.)

  1. Remove carburetor from inlet manifold.
  2. Back out and remove air valve adjusting screw and spring.
  3. Remove upper half of carburetor – 5 screws – taking care not to injure gasket or air valve plunger.
  4. Remove float pivot pin, float , float valve and valve seat. The seat can be removed with a 7/16″ snap-on socket wrench.
  5. Install new float valve and seat assembly.
  6. Check the float level. It is important that the float level with gasoline in the bowl be exactly 11/32 from the top edge of the bowl without gasket to the top center of the float. If the float level at checking is lower than 11/32, bend float level “up”. If the level is higher than 11/32, bend float lever “down”.
  7. Re-assemble carburetor.
  8. For setting and adjusting the carburetor, see latest instructions. This is important.

The following parts are required for the manifold cover and carburetor float valve and seat assembly:

185782Inlet manifold cover assembly
140769Cover and manifold rear clip assembly
127B158Rear clip binding screw
1A14140Binding screw nut
2V104BCover screw
137203Toggle lever screw
227525Washer
219B113Lockwasher
1A10470Control clip screw
1100953 (hand written) 101013Carburetor float valve and seat assembly

We will supply inlet manifold covers for all 436 Models shipped todate and the new float valves with seats for motors up to DCF546. These parts will be shipped as fast as we will be able to supply them.

SPECIAL INSTRUCTIONS FOR MODEL 636 OR 637 INDIAN SPORT SCOUTS
WITH DAYTONA OR SAVANNAH MOTORS
INTRODUCTION

The following confidential instructions and information have been prepared for owners of Model 637 Indian Sport Scouts with Daytona motors. They also supply to previous Sport Scouts built with Savannah motors.

Daytona motors are all built in a separate department by skilled mechanics who thoroughly understand the preparation of motors for competition purposes. Each motor, therefore, is assembled with special parts, clearances, and adjustments, to give maximum performance. Following assembly, each machine is given a dynamometer test for horsepower and top speed.

In order that the original efficiency and performance of these machines be maintained, read carefully these instructions and follow them. By so doing you will be able to keep your machine at the top in Class “C” Competition.

BREAKING THE MOTOR IN

Although Daytona motors are assembled with extra clearances to insure free running at all times, it is necessary that these motors be broken in carefully.

Machines should be run at speeds varying from 35 to 55 miles per hour for about 150 miles. This for the purpose of obtaining a high polish on cylinder walls and find seating of pistons, piston rings and bearings. More miles of breaking in may be necessary if the motor does not fell like its ready to go.

Never open the motor up until the oil in the tank is warm. Consult instructions on oiling.

Never allow the motor to labor in high gear. Consult instructions on gearing and ignition.

OILING

The use of the proper oil for any given condition or type of event is absolutely necessary if maximum performance and long life of the motor parts is to be obtained.

For ordinary road riding, endurance runs, etc., where average speeds are below 60 miles per hour, use Indian Valvoline SAE-50 or 60, preferably SAE-50, and change the oil every 500 miles regardless of condition of the oil. Cheap oils give nothing but grief. Remember your motor is just as much oil cooled as it is air cooled.

For competition riding on one-half or one mile tracks, T. T. Racing, etc., where average speeds are 60 miles per hour or higher, use Indian Valvoline SAE-50 or 60 or Crystal Oilzum and change oil every meet, or in case of longer races, at least every 100 miles.

Be sure the oil pump is set wide open.

Be sure that the oil in the tank has become sufficiently warm before opening up the motor .

IGNITION

Daytona Motors are fitted with magneto ignition to meet varying conditions and to reduce weight when machines are stripped for competition purpose.

The spark advance setting at the factory is 5/8″. Spark plugs fire when pistons are 5/8″ before top dead center on the compression stroke.

The magneto breaker point setting is .015. If for any reason, it is necessary to replace magneto points. use only .015 setting since any variation of this figure will change the spark advance and also the efficiency of the magneto.

Due to the high spark advance, it is advisable to retard the spark slightly with the hand grip during acceleration. This is helpful in preventing laboring of the motor during acceleration in high gear.

Keep spark plug cables clean and in good condition. Replace as often as necessary. Be sure cable connections at the magneto are secure and tight.

SPARK PLUGS

The use of the proper spark plug for any given meet or temperature is most important.

Spark plugs should be inspected regularly for cracks and leaks. Plug porcelains and electrodes should be kept perfectly clean.

For high speed racing and especially on warm days, use Champion JA-12 plugs. For road touring or for racing in the spring or fall when the days are cool, use Champion JA-11 plugs.

VALVES

After every race meet or long races, valves and valve seats should be inspected and ground if necessary. Perfect valve
seats are required for maximum performance and it is suggested that the valve seats in the cylinder be reseated if there is any evidence of distortion or pitting.

The correct tappet clearance for the intake valve is .006 and for the exhaust valve .008. These tappet clearances should be obtained with a feeler gauge and with the motor cold.

Valve springs should be checked regularly for weight. Replace if necessary.

PISTON – RINGS – CYLINDER HEADS

The correct piston clearance is .008 minimum. Pistons should be kept free from high spots and ring grooves should be free from all carbon.

Piston rings should be checked regularly and replaced often, or when compression and top speed fall off. The correct ring gap for the top ring is .018. For the second ring .016 and for the third ring .014. Use Indian rings only as they are
made especially for these motors.

Cylinder heads should be kept free of carbon and the combustion chamber polished. If the cylinder head gasket is replaced, be sure that it is the correct one for the head being used and that there are no projections of the gasket into the combustion chamber. Gaskets should be trimmed if necessary.

In replacing cylinder heads after removal, be careful to replace the one short cylinder head bolt over the intake nipple on each cylinder.

CHAINS

The primary chain between the motor and the transmission should be kept in the proper adjustment. Do not have this chain too tight. Follow your Indian instruction book for adjustment.

Keep the rear chain clean at all times. Do not run it too tight. Tight chains reduce top speed.

TIRES – BRAKES – WHEELS

One of the most important safety features of Class “C” Competition is to regularly inspect tire equipment. They should be kept in first -class shape at all times. Tire pressures should be between 30 and 40 lbs. for free rolling and safety. Keep wheel bearings adjusted with proper side play and properly greased for free running. If brakes are relined at any time, be sure linings do not drag on the brake drums.

CLEARANCE CHART-DAYTONA MOTORS

Intake valve clearance.006″ cold motor
Exhaust Valve clearance.008″ cold motor
Valve Seats35 degrees
Valve spring weights100 to 105 lbs. at 1-7/8″ height
Piston clearance.008″ minimum
Ring gap.018″ top ring
.016″ 2nd ring
.14″ 3rd ring
Connecting rod lower bearings.0025″ to .003″
Connecting rod upper bushings.003″
Connecting rod side play.015″ to .020″
Flywheel end play.010″ to .012″
Drive shaft bearings.0015″ minimum
Spark advance5/8″ before top dead center
Magneto Points.015″

GEARING

Many competitive events have been lost by riders who have failed to select or determine the proper gear ratio for the machine in that particular event.

Factors which influence the proper selection of gearing are:

  1. Condition of the motor.
  2. The condition or type of surface over which the machine is to be ridden.
  3. Weather.
  4. Number of turns and length of straight-away in the course.
  5. The size of the rider, large or small.
  6. The position of the rider on the machine.

There is no possible way to determine in advance the exact gearing that should be used for any event. However, the recommendations given will be correct, or nearly so, and changes should be made after trial runs. Do not use a gearing that will let the motors turn up a higher R.P.M. than necessary; but be sure you are getting the best possible lap speed. Gear motors to the faster parts of the track or course and use throttle or gears on turns and corners.

Indian rides are urged to keep records of all meets and events indicating, condition of course, type of event, speeds obtained, gear ratios used, and weather. Such records will be helpful the following year or for similar events. Experience is the best teacher.

The following chart shows gear ratios for the various sprocket combinations available. If a rider expects to compete in all types of Class “C” events, he should have the range of sprockets shown -16-17-18-19 and 20 tooth countershaft sprockets; -36-39-40-42 and 43 tooth rear wheel sprockets. The 19 and 40 tooth sprockets are furnished with the machines. The 39-42 and 43 tooth rear wheel sprockets are ¼” wide for dirt clearance on tracks.

COUNTERSHAFT SPROCKETS

Rear Wheel1617181920
364.884.594.334.123.90
395.264.974.694.444.22
405.415.094.824.564.33
425.69
435.83

This chart for 18″ x 4.00″ Rear wheel Tire Primary. Ratio 2.166 to 1

Suggested gearings which have been successfully used on Daytona Sport Scouts are –

Road Races such as Daytona and Savannah

19-36 =4.12
20-39 =4.22 – most popular
18-36 =4.33

1 Mile Speedways or Tracks such as Langhorne and Oakland:-

19-39 =4.44
19-40 or 17-36 =4.59 – most popular
18-40 =4.82

1/2 Mile dirt tracks

16-42 =5.69
16-43 =5.83 – most popular

For endurance runs, road touring, and road races where rough dirt roads are encountered.

19-40 =4.56 – standard gearing

Remember all motorcycle riders are sportsmen. Ride hard to win, but ride within your ability. Play the game fair and square. Take your beatings gracefully. If you are out or in, help your fellow Indian Rider. Teamwork has won many a victory.

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