S&S Cycle Sidewinder 3 5/8 Big Bore Cylinders for 1936–1999 Big Twins - Manual (Page 6)

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5. Clearance Frame (All)
NOTE: Piston stability in cylinder bore is enhanced by using pistons with long skirts. S&S® Sidewinder® kits are designed with this in mind regardless of
stroke used. As stroke gets longer cylinder height/engine height must be increased. Convenient frame fit, stock rocker cover to frame tubes and/
or rocker cover to gas tank clearances have to be sacrificed. Hence, all Sidewinder® kits with taller than stock cylinders require checking in these
areas. We have found that engines with cylinders up to .125" (1⁄8") taller than stock will usually clear.
To check and clearance frame, perform following steps:
A. After crankcase boring operation, leave cases together and bolt cylinders with base gaskets in place. If base plates are to be used, be sure
they are installed also.
B. Bolt heads on cylinders with head gaskets in place using two bolts and washers provided for each head. Harley-Davidson® Evolution®
heads and cylinders are held in place simultaneously with head bolts provided.
C. Install rocker boxes, with gaskets, etc.
D. Slip mocked up engine in place in frame.
E. On rigid mounted engines, rear rocker cover may contact frame tube(s).
NOTE: S&S® recommends there be .060" minimum clearance between engine and other chassis components on rigid frame installations. Rubber
mounted engines require .125" clearance minimum. Up to .060" or .070" may be ground from rocker box cover in some areas for clearance. If cover
is ground, be careful not to break through.
Excessive material removed from rocker cover may damage cover causing oil leaks.
Excessive material removed from frame may cause structural damage and possible failure resulting in personal injury to you or others
near you.
F. Hold each gas tank in place separately. Note and mark points of contact with magic marker. Some models may be worse than others. Grind
rocker cover if necessary, but be careful not to break through cover as they are thin in some places. See step E above. Obtain at least .060"
minimum clearance for rigid mounted engines and .125" minimum for rubber mounted engines.
NOTE: Additional room may be gained by slotting front gas tank mounting tabs if rocker cover clearancing is inadequate.
Grinding and/or peening gas tank may damage tank causing leaks.
Unwarranted gasoline leaks from gas tanks may overflow on surrounding area where it could catch fire possibly causing personal
injury to you or others near you.
6. Modify Crankcases for Oil Returning from Heads (All Crankcases 1953 and later)
Crankcases 1953 to 1984
NOTE: This operation is necessary on any Sidewinder® installation for knucklehead, panhead or shovelhead engines where oil from cylinder heads is
being returned to crankcases via oil return passageway in cylinders.
While cases are still bolted together, perform following steps:
A. Place cylinder base gasket on cases and mark and centerpunch oil return holes. Make certain you have gasket on correctly by checking oil
hole location with each Sidewinder® cylinder.
B. Drill 1⁄4" diameter holes perpendicular to gasket surface 5⁄16" deep. See Figure 1, next page.
WARNING
WARNING
CAUTION
CAUTION