Caution – S&S Cycle Bore Stroker Kit 3 3/16 for Harley-Davidson Sportster Models User Manual

Page 9

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Improper pinion gear spacing may cause incorrect breather
timing and poor oil scavenging from flywheel cavity. This
condition may cause unwarranted engine oil leaks around
gaskets and seals and probable oil burning due to oil blow
by past piston rings.

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Improper pinion gear spacing may cause unwarranted
contact between pinion gear shim and pinion shaft splines
resulting in damage to gear cover and/or other engine
components.

Check clearance between pinion gear and cam cover
bushing. Recommended clearance is .005”. Place shim
between pinion gear and gear cover. Harley-Davidson

shims, H-D

#18268-48, are .015” thick each and may be

used for this purpose.

Piston to Valve Clearancing (All)

NOTE - All valve spring spacing, rocker arm to collar and rocker
arm to rocker cover clearancing must be done before piston to
valve clearancing can be checked.

S&S

pistons have sufficient valve clearance when used with most

street high performance cams. However, we recommend that
valve clearancing be checked if other than stock cam is used.

Check piston to valve clearance in following manner:

Assemble engine with exception of cylinder heads. Be
sure valve pockets are positioned correctly.

NOTE - Larger intake pocket must be toward center of engine.

Turn engine over until front piston is at top dead center.
Paint area around valve pockets on pistons with
machinist’s blue.

Place valves in cylinder head leaving off springs and
retainers. Place head on cylinder and secure with
one bolt.

Lower valves until they contact piston. Rotate valve
marking painted area.

Remove head and check points of contact. Valve should
fit in recessed area machined in piston dome.

NOTE - S&S recommends at least .060” clearance around
periphery of valve.

If insufficient clearance exists, remove piston and
grind valve pocket until head of valve fits flush with
proper clearance.

Repeat procedure for other cylinder head.

Spread layer of putty into valve pockets in both pistons.

Assemble cylinder heads and bolt assemblies on
cylinders with head gaskets in place. Install pushrods
and adjust to simulate final assembly.

Turn engine over in normal direction of travel two
complete revolutions.

Disassemble engine and check thickness of putty in
valve pockets.

NOTE - S&S recommends at least .060” clearance between
valve and piston valve pocket recess. While .060 clearance is
recommended minimum, it is advisable to have .080 and up,
if possible.

Insufficient clearance between piston and valves may cause
them to contact each other during operation resulting in
damage to piston and valve train components.

If less than .060 clearance in any area exists, grind area
until proper clearance is achieved.

Final Top End Assembly and Engine Installation

NOTE - All previous steps must be completed.

We recommend installing cylinders without heads bolted to
cylinders for two reasons.

Combined weight of cylinder and cylinder head
makes assembly cumbersome and hard to handle
during installation.

Separate installation of cylinders and cylinder heads
permits more leeway for adjustment to achieve a better
manifold fit.

Installation of cylinders and cylinder heads as assemblies may
result in damage to rings and piston assemblies. Improper
intake manifold fit may cause intake air leaks/improper fuel
mixture and result in damage to engine components.

CAUTION