S&S Cycle Bore Big Twin Stroker Kit 1936–1999 3 7/16 - 3 1/2 User Manual

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BREAK-IN PROCEDURE

This procedure applies to all engines with close fit pistons.

NOTE: These engines must be broken in. They will feel extremely strong so resist the impulse to turn it on. Break it in properly.

Lugging engine at low rpms and/or running engine prematurely at high rpms may result in damage to pistons and/or other engine
components. S&S® voids its guarantee if engine is not broken in properly.

1. On initial engine startup, don’t just sit and idle motor while you admire your work, or tinker with minor adjustments. Heat buildup can be

excessive. Do not let engine overheat.

IMPORTANT NOTE - V2®s ONLY - Proper first time engine start-up and break-in for first 15 minutes is critical to achieve permanent and lasting head
gasket seal. Upon initial start-up, idle engine at 1000-1500 rpm until cylinder head temperature reaches about 250°. Do not crack throttle or put any load
on engine during this time. Heat buildup is necessary to cause heads and cylinders to expand and seal. Do not let heat get excessive. Prior to initial start-
up, a .003"-.005" “feeler gauge” will fit between head gasket and head and cylinder gasket surfaces stopping at fire ring on head gasket. Warming engine
as instructed will tightly close this gap producing a good, lasting seal. Most V2 head gaskets are blown at this time.

Improper initial V2 engine start-up may cause head gaskets to fail prematurely.

2. First 50 miles are most critical for new rings and piston break-in. Most engine damage will initially occur during this period. Keep heat down by

not exceeding 2500 rpm. Vary speed. Do not lug engine.

NOTE: Retighten cylinder base nuts and head bolts as necessary after engine has been run.

3. Next 500 miles should be spent running engine no faster than 3500 rpm or about 50-55 mph. Do not lug engine and continue to vary

speed.

4. For balance of first 1000 miles, speed can be run up to 60-70. Continue to run engine at all different speeds including lower 40-45 mph

ranges. Do not lug engine.

5. 1000-2000 miles basically same as before but a little more liberal with rpm range. Avoid overheating and lugging engine – no drag racing,

trailer towing, etc.

6. 2000 miles and up – have fun!

CAUTION