S&S Cycle Super Stock and Special Application Crankcases for 1936-99 Big Twin Engines - Manual (Page 13)

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Selecting color where columns intersect provides proper fit for normal service. If looser fit is desired, select bearing color directly to right of color
indicated from selection process. If color indicated from selection process is located in right color column, go to next row directly below and select
color in left color column.
2- Fitment method B - Use Chart 2 below.
a- Refer to information tag on crankcases to determine final honed size of inside diameter of pinion shaft main bearing race.
b- Measure pinion shaft bearing surface diameter.
c- Subtract pinion shaft bearing surface diameter from pinion bearing race inside diameter.
d- Select range in left “Bearing Race Diameter minus Pinion Shaft Bearing Diameter” column where difference best splits high and low
parameters of range. Corresponding color bearing set in right “Bearing Color Code” column provides proper fit for regular service.
S&S® Pinion Shaft Main Bearing Fitting Charts
For 1987 and later style bearings
EXAMPLE: Pinion bearing race inside diameter is 1.7510”. Pinion shaft bearing surface diameter is 1.2499”. 1.7510” minus 1.2499” is .5011”. Difference of
.5011” splits “.5009 to .5013” range in third row exactly. Corresponding “BLUE” color code in right column should be used. Notice that .5011” fits in several
range groups. Try to select group where difference falls closest to middle of range. If you are not sure, select color that corresponds with group closer to
top of chart. This will provide slightly looser bearing fit and help prevent bearing seizure. Selecting next color up on chart may also be done if looser fit is
desired for competition applications.
D- Stroker flywheels and connecting rods
1- Flywheels - S&S crankcases feature adequate flywheel crankpin nut to case clearance for strokes up to and including 5”. Recommended
clearance between flywheels and scraper is .008” - .010”. Stock diameter flywheels are 81⁄2”; standard small diameter flywheels 81⁄4”. S&S
crankcases can be ordered machined for either or specially machined for as small as 8” diameter.
2- Connecting rods - S&S crankcases feature adequate clearance for most brands of heavy duty connecting rods.
* All reference to Harley-Davidson® part numbers is for identification purposes only. We in no way are implying that any of S&S® Cycle’s products are
original equipment parts or that they are equivalent to the corresponding Harley-Davidson® part number shown.
NOTES
It is important to confirm flywheel diameter is correct for crankcases. Flywheels that are too large will not fit in crankcases. Flywheels that are too small
•
will leave too large a gap between flywheels and oil scraper resulting in poor oil scavenging and possible oil consumption problems. If flywheel diameter
is smaller than diameter crankcases were machined for, scraper should be built up to provide proper clearance at rim of flywheels.
Clearances between crankpin nut - case and connecting rods - case must be checked by engine builder during assembly. Engine damage resulting from
•
improper clearances is not covered under warranty.
Abnormal contact between moving engine components due to improper clearances may cause premature wear, damage or failure of
these parts or other components.
E- Camshaft - 1948 and later - S&S cases have sufficient clearance for lift up to .631” with 1.000” base circle camshaft. If cam with greater lift
is to be used, clearance between rear cam lobe and pinion shaft bearing race must be checked and adjusted if necessary. A special pinion
shaft bearing race, pre-clearanced for use with cams up to .798” lift with a 1.000” base circle is available. It is especially important to check
knucklehead style cases since most cams available are aftermarket grinds with varying specifications.
Big Twin Bearing Race Diameter
Pinion Shaft Bearing Diagram
1.2498 - 1.2500 1.2500 - 1.2502
1.7511 to 1.7513
Red
S&S® 31-4017
H-D® #24628-87 Blue
S&S 31-4018
H-D #24643-87
1.7509 to 1.7511
Blue
S&S 31-4018
H-D #24643-87 White
S&S 31-4005
H-D #24626-87
1.7507 to 1.7509
White
S&S 31-4005
H-D #24626-87 Green
S&S 31-4016
H-D #24628-87
Bearing Race Diameter Minus
Pinion Shaft Bearing Diameter
Bearing Color Code
.5005 to .5009
Green
S&S® 31-4016
H-D® #24628-87
.5007 to .5011
White
S&S 31-4005
H-D® #24626-87
.5005 to .5013
Blue
S&S 31-4018
H-D #24643-87
.5011 to .5015
Red
S&S 31-4017
H-D #24641-87
Chart 1
Chart 2
CAUTION