American Motorcycle Dealer AMD 243 October 2019 | Page 53
M-8 Rocker Arm Tower Stud
and Beehive Racing Valve
Spring Kits
Pacifica, California based Kibblewhite Precision
Machining is offering what it describes as a
"premium" rocker tower solution for '17-'19 M-8
engines.
The kits include nuts machined from heat treated high
tensile billet steel and heat treated 180,000 PSI
aircraft alloy steel studs - both have rolled threads for
the greatest possible strength and are black oxide
treated for enhanced corrosion resistance.
Company President Will Kibblewhite explains that
"because the stock M-8 rocker shaft bolts can stretch,
the shaft can move in the saddle, leading to deformed
saddles, cracked rocker towers and broken rocker
shafts.
"KPMI M-8 rocker tower studs are made from
180,000 PSI yield strength, fine grain, heat treated
aircraft grade steel; the lower portion of the stud is
0.810" long, which maximizes the length of the
thread engagement.
"The threads are rolled, not cut. Rolling gives the
threads a superior surface finish and compresses the
material, making the threads denser, for the toughest
and strongest possible thread, and the studs are black
oxide treated to increase corrosion resistance.
"The combination of the material, thread type and the
length of the thread engagement maximizes clamping
force, makes the assembly more stable than stock, and
reduces the chance of failure due to the stretching and
flexing that the factory bolts are subject to."
The nuts are single point machined from high tensile
strength aircraft alloy steel. During the machining
process, close tolerances and smooth surface finishes
are maintained - two critical factors for achieving
correct fit and torque. After machining, the nuts are
heat treated to a specific depth. This creates hard,
wear-resistant working surfaces, while retaining a
ductile core to prevent cracking under load. The
premium black oxide treatment provides excellent
corrosion resistance and appearance.
Also seen here is Kibblewhite's 0.625" lift beehive
racing valve spring kit for '17-'19 M-8 engines. The
company says that its R&D team conferred with some
of the best known builders in the world to arrive at a
consensus for the characteristics of this new kit.
"Combining feedback from these builders with our
engineering team's stringent design criteria for wire
stresses, fatigue life and manufacturing processes has
allowed us to create a unique spring, designed
specifically for the M-8.
"The progressively wound, ovate wire, beehive springs
undergo proprietary heat treatment and shot peening
processes. These complete kits provide the spring
forces required for high lift camshafts and sustained
high rpm."
The kits are supplied with either tool steel or titanium
retainers to minimize reciprocating mass, special M-8
high lift beehive valve springs, heat treated steel bases
and steel clad top hat seals with a Viton sealing
element.
KIBBLEWHITE PRECISION MACHINING
Pacifica, California, USA
Tel: 650 557 2046
[email protected]
www.kpmi.us
High Speed - Low Drag
Bitwell's new 100% leather Borrego
gloves have "rugged
reinforcements in friction zones
coupled with perforated panels for
increased air flow. A positive wrist
closure and high-impact knuckle
guards contribute to the coveted CE
rating - but we’ve made them
aesthetically low-key so you don’t
look like a transformer while riding."
Biltwell, USA, www.biltwellinc.com
www.AMDchampionship.com
AMERICAN MOTORCYCLE DEALER - OCTOBER 2019
53