American Iron Magazine December 2017

TECHLINE • BY DONNY PETERSEN
Part II: Powertrain rigidity 1929-2018
as power surges through the
powertrain. Handling and vibration
may seem like separate
subjects, but both intertwine with the
From 1929–64, classic V-twin Harley
engines and transmissions bolted
separately and independently to the
head
engine introduced in 1929, the
Knuckle in 1936, and the Panhead in
nents
depended on correctly machined
bers.
All I have to say is “good luck.”
Each engine and transmission with the
heavy rotating clutch pack vibrated
they did.
A thin, stamped sheet metal chaincase
shielded the primary chain, engine
connecting the engine and transmis-
-
grating through the churning internal
chain and assemblies.
-
comes handling impediments.
In 1965, the last-year Panhead
engine and transmission morphed into
changes and improvements. One was
cast inner and outer aluminum primary
derby was incorporated to allow easy
access to the clutch. Oil-impregnated
-
removal was necessary to service these
Right flywheel
Pinion shaft
Wrist pin
The sprocket (left) side flywheel and pinion (right) side are one piece. The weight has been redistributed to produce
less inertia, which will mean faster acceleration off the line. Pistons have a Teflon coating to assist in break-in.
Connecting rods are massive with corresponding increased size wrist pins and bearings. Pinion shaft, pinion bearing,
and crankpin diameters make Evo ones look puny by comparison.
was partially resolved in 1970 with a
new aluminum outer primary chaincase
tion
eliminated with the 1985 switch to
wet clutches cooled in a wet sump oil
bath also suppressed noise.
-
-
heavy 1965-69 chaincases now added
wonky handling issues and decreased
Piston rings
Piston circlip
Left flywheel
components. Furthermore, accurate
and stable primary chain alignment
was now possible since the engine and
vibratory causes that required techno-
-
its competitors.
-
Continued on page 95
24 / American Iron / Issue #358 AIMag.com
Piston
Female (fork) connecting rod
Floating
thrust washer (2)
Crank pin cap
Con rod bearings
Hollow crank pin
3 oiling holes
.007" straight press fit
The slotted flywheel
allows a sensor to read
crank speed and position
for both carb and EFI spark
matrix ignition maps
Sprocket shaft
Male (knife) connecting rod
The pinion shaft supports the geroter (Sportster style)
oil pump inside the engine. It also acts as the drive for
the timing plate mechanism via a “silent” chain that
eliminates timing gears in the fathead