New Bikernet Security Beast, Cash, who works
closely with his partner, Tank.
There's a code going around regarding Twin Cams. Lee
Clemens pointed it out to me first, when he broke down on the
way to Myrtle Beach on his FLH Twin Cam, with 25,000 miles on
the clock. "The cam bearings disintegrated and took out the
lower end," he said. The rumors are that the chain drive tension
increases the load on the cam bearings and they begin to wear
until they come apart between 10,000 miles, and as Lee Pointed
out, 25,000 miles.
I discussed this with Gene Thomason of Gene's Speed Shop
in Carson, California. We had an interesting chat about Evos and
Twin Cams and which are the best. Gene and his dad, Gene Sr.
worked for Bartels H-D in Marina Del Ray and for the Harley-
Davidson fleet center for a decade. They know Twin Cams, every
model and configuration. Gene Jr. is also an avid H-D top fuel
drag racer, so he knows performance gremlins and how to deal
with the stresses of performance enhancements.
Is he a surfer or drag racing maniac? That's Gene
"The Twin Cam exceeds the Evo, especially when it comes to
performance," Gene pointed out. "Since it's mated to the
transmission, alignment is enhanced and the cases are heavier
and stouter design to handle the rigors of big-inch engines. The
Twin Cam configuration allows the pushrods to be shorter and
run at less of an angle to the rockers. The hefty cams don't ride
on the cam cover, but a separate plate specifically designed to
hold the cams more securely and in alignment with the case
I like the Evo for its pure tradition, historic refinement and
minimal components, but everything he pointed out was correct
and a consideration for performance-minded riders. I asked
Gene if H-D would ever install gear- driven cams and he
pointed out that noise is a factor. Factories are allowed a
particular level of noise to comply with federal standards. That
level applies to the entire driveline from the exhaust to the
"Harleys like their exhaust rumble, so they try to keep the
driveline quiet," Gene said.
You'll notice that Victory runs a noisy gear-driven
primary, but the exhaust is quieter to level the regulatory
playing field. I also reached our to our resident Bikernet.com
Tech Expert, Pablo. Here's what he said:
”I hope you replaced the inner case INA (H-D) cam
bearings with Torrington roller Bearings. Get them from Drag or
CCI. The new 96-inch H-D engines also use INA inner case cam
bearings, just a larger size.
”The Twin Cam INA bearings have the same issues like the
EVOs did. They don't hold up with any performance work added
to the engine. Cams, heads, stroker kits, and high-compression
pistons enhance pressure on internal components. The
Torrington bearings have more rollers, more bearing contact
surface, and better support.
“Good choice on the S&S gear drive setup for sure. You
might consider one those billet cam plates also. Check your
Flywheel run-out also.”
I rode the 2003 Road King, with a measly 12,800 miles on
the clock, to Gene's Speed Shop on Normandie in the Torrance,
California Gasoline Alley (310) 618-1908. We pulled the bags
performed a dyno run for a reference, although I wasn't
switching the cams for additional performance. I had mid-range
SE-203 cams in the bike with Screaming Eagle Heads, two-into-
one Screamin' Eagle Exhaust and Terry Components closed-loop
enhancement to my H-D EFI system. The bike ran terrific. The
Dyno noted 68 HP at 6000 rpms and 84 pounds of torque at
"A stock 96-incher puts out 52 horses and 65 pounds of
Torque," Gene said while straddling the King in his dyno room.
We carefully removed the exhaust sensor before
yanking the pipes off.
The 203 mid-range cam had .510 and .483 lift (intake and
exhaust), and .234 and .239 duration. The S&S 570G cam set
had .570 lift with .240/.255 duration. The S&S brochure point
out the following benefits:
Reduced Maintenance: There are no chain
guides or shoes to wear or replace and no debris from wearing
guides or shoes to contaminate oil supply.
Consistent cam timing: Cam gears are keyed with
a light press fit. Chain and tensioner induced variations are no
longer a problem.
Load: Eliminating the chains and tensioners
eliminates excessive side loading of cam bearings.
Critical sprocket alignment is unnecessary. Use of
precision-machined spacers is eliminated.
Performance benefits: This system maintains
accurate valve timing when using high performance valve
springs with higher spring forces.
Performance fitment: Higher cam lifts can be used
without decreasing cam base circle. Gear-driven rear cam
rotates in opposite direction from chain-driven cam. Lobes on
front and rear cams never point toward each other, allowing
increased lobe height.
With the S&S Gear Drive Cam kit and their Pushrod set
(which is required), we had all the components to perform the
job, including gaskets. All S&S parts are guaranteed for a year to
be free of manufacturing defects in materials and workmanship.
The pushrod kit even comes with all the covers and O-rings,
minus the centers with the springs and washers. We hoped the
operation could take place without removing the rocker boxes. If
we had to remove the boxes, we would need additional gaskets,
not included in the kit.
The reason S&S supplies the covers include the proper
length to afford us the ability to adjust the pushrods.
"Gear drives also prevent chain drive drag on a performance
engine," Gene pointed out as he started to remove the air
cleaner and pipes after the bike cooled.
We had to loosen the exhaust sensor, before removing the
pipes. We removed the right footboard and Gene prepared to
drop the oil drain plug.
"What's the deal?" he said. "There's still Bonneville salt on
the drain plug."
I didn't have an answer and just kept my mouth shut and
took notes. Gene pulled the sparkplugs, disconnected the
battery and turned the engine over until the rear cylinder
pushrods were down, after removing the pushrod cover clips.
With bolt cutters he cut the non-adjustable pushrods and tossed
them in the trash. Then he turned to the front cylinder. The S&S
booklet recommended we jack up the bike securely, put it in 5th
gear, and rotate the rear wheel until both lifters and pushrods
for either cylinder are at their lowest point on the camshaft (TDC
of the compression stroke). Both pushrods for that cylinder will
not be under pressure from the valve springs and will rotate
with light finger pressure.
Here's a note regarding the adjustable pushrod
requirement: 510G camshafts may use stock style
non-adjustable pushrods instead of adjustable pushrods. If
installing non-adjustable pushrods, disassemble and assemble
rocker box per Harley-Davidson instructions. All other S&S gear
drive cams require installing adjustable pushrods. As a
timesaving measure, the stock pushrods can be removed with
bolt cutters. Be sure to heed cautions and warnings: use bolt
cutters and not cutoff wheels to prevent debris from entering
the engine. Cutting pushrods without releasing the spring
pressure (lowest point on the cam) may result in bodily damage
or a dead dog, if he's in the way.
Hydraulic lifters, guide pin and lifter block.
Gene removed the lifter blocks, which aren't lifter blocks
anymore. They are lifter covers that hold a hardened guide pin
in place (the pin prevents the lifter from spinning) and seal the
area with gaskets and O-rings. Throughout this process, we
used a variety of JIMS tools to remove and replace components
without risking damage. He removed the cam cover bolts and
the cam case cover. It's not necessary to remove any ignition
sensor from the cover.
Here's the original Screamin' Eagle cams set in place. There's
one chain on this side of the support plate from the pinion shaft
to the rear cylinder cam. On the back side a chain runs from one
cam to the other.
We used a JIMS tool to hold the cam chain tensioners
locked away from the chains after the cam cover was removed.
Another JIMS tool held the gears in alignment so we could
remove the gear bolts from the cam and pinion shaft.
We popped the gears off then the chain tensioners were
Then we moved onto removing the cam set and guide plate
all as one piece. The S&S booklet documents specific fastener
removal order for the oil pump and cam support plate. The cam
system slipped right out of the engine case. In some cases, a
press will be necessary to remove the cams and cam bearings
from the support plate with a JIMS tool. In this case, the cams
and stock bearings slipped right out of the support or alignment
Another S&S Note: It's not necessary to
remove the oil pump from the engine to complete this
installation unless grinding in the gear case must be performed
for clearancing. If grinding takes place, all gear case
components must be removed and all holes taped off with duct
tape to avoid contamination.
There's another JIMS tool to support the plate and install the
new S&S bearings. Gene used a 1 1/16th socket as a guide to
tap the new bearings in place after smearing them with Redline
assembly lube. A few light taps and they slipped into place.
S&S supplied a new outer bearing retaining plate and it only
slips on one way. S&S recommends checking the clearance
between the bearing retainer and the woodruff keys securing
inner gears to the cams. Remove material from the retainer as
needed to provide .030-inch clearance between keys and
retainer. Gene installed the bearing retainer plate and used blue
Loctite and tightened the screws to 20-30 inch-pounds torque.
Gene grabbed the new S&S cam set and washed any anti-
corrosion packing residue from the surfaces. Then he slipped
the correct cam in the correct hole. The longer cam with the
keyway is the rear cam. The two cams have alignment notches to
indicate how they should be positioned. He used a press to
install the cams in the cam plate, pressing the tall cam first until
it was even with its mate, then pressed both into place. He
double-checked to verify that the cams were aligned properly.
Then he coated the crap out of all the new components with
This shot shows the stock roller bearing. The new S&S
bearing is a ball bearing set.
He inspected the brass pinion shaft bushing for severe wear
and performed a quick test fit to insure that no cam lobes would
hit the case casting under the lifters. This wasn't a high
performance set of cams, so there wasn't a problem, but it was
good to inspect.
It's a lousy photograph, but it is a JIMS tool removing the
case cam bearing.
Again he used a series of JIMS expansion tools to remove
the case cam bearings. The case cam bearings are the ones
known to go to shit at between 10,000-25,000 miles especially
under performance loads. The stock bearings are smaller,
shorter and fewer in the race than the S&S performance roller
Again a JIMS tools was used to carefully tap the new bearing
into the cam gear case. Gene drove the new bearings into the
case material until they mated with the inside case lip. While the
case was still open, he inspected the oil pump for scoring. He
also checked the back of the cam plate where the oil pump
Gene also cleaned the lifter block gasket surfaces while the
case was open. Any material that inadvertently fell into the case
could be easily removed.
The head of the screwdriver held the oil pump
pick-up just the correct distance from the floor of the case.
He installed the cam set and bolts loose and spun the cams
to insure there was no binding or problems. He tightened the oil
pump Allen fasteners, first alternating sequence, one through
four to 95-inch pounds. He performed this task while making
sure there was a gap beneath the pick-up opening in the
bottom of the pump. If there was no gap, the cam case would fill
with oil. He used a large flat-bladed screwdriver as a guide to
insure the gap didn't disappear during the tightening process.
Then Gene tightened the cam plate to factory torque specs
and installed the key and rear drive gear timed with the slots on
the components. There's no way to go wrong unless you're
blind. He almost forgot the front cylinder cam clip ring that
prevents the cam from backing out.
"I never had one come loose," Gene commented.
Gene installed the big cam gear bolt with Loctite and
to 35 foot-pounds. The smaller gear, with washer and Loctite,
was torqued to 25 foot-pounds. S&S supplied new fasteners
with the gears, but he used the stock machine washers (S&S said
you don't need 'em). Next, he
replaced the hydraulic lifters.
Before replacing the chromed case cover Gene checked this
area for clearance since the S&S pinion gear is larger than the
"I always need to think about pushrod order and rotate the
engine so the rear valves were down as far as possible,” Gene
said. The new adjustable S&S pushrods were just two lengths.
The two long ones were used in the exhaust sides.
Replacing the pushrods, tubes, lifter block, guide
pin and gasket at one time. A miracle.
S&S supplied all new covers minus the center spring
retainers. Gene worked with the lifter blocks and pushrods to
determine whether he could install the pushrods without
removing the rocker boxes. A larger lift cam could pose a
problem; these units were very close to being too long. Gene
had to feed the intake pushrod, the lifter block gasket, and the
pushrod covers into place in one dainty motion. It was a trick to
hold and guide all the elements, but it worked.
There's that surfer in the chrome. He was kind enough to
relinquish his trademark pushrod cover containment special
tool. Even JIMS doesn't have this one in their stock, just two
I also learned the code of pushrod adjusting.
Gene paints the adjuster flat with H-D touch-up
paint and counts four turns, or you can go for 24 flats.
"You lower them all the way," Gene explained. "Then you
take all the slack out, and screw them down four turns. The
hydraulic lifter doesn't move. You've opened the valve four
turns. That's why you can't turn the engine over for ten minutes.
If you did the valve could smack the piston. So you
need to wait ten minutes for the lifter to settle, and then adjust
the front cylinder."
After all was said and done, the pushrods should spin when
the engine is turned over and the valves cams lobes are down.
Again Gene checked the cam cover for clearance, since the
S&S gear is larger than stock, but we still didn't face any
clearance problems. He tightened the pushrod jam nuts on the
rear cylinder, checked for spin, then moved onto the front
cylinder pushrod adjustment. He waited another ten minutes,
checked for pushrod spin, turned the engine over once for a
final inspection then replaced the cam cover.
Note:In this case, with new S&S pushrods, the
adjuster spins on a fixed threaded shaft, and the jam nuts
tighten down against the adjuster and not up against the
Gene added three quarts of Redline 20-50 synthetic oil and
replaced my Screamin' Eagle exhaust system.
"It should hold four with a new filter," Gene said.
Then I went for a ride.
We dyno'd the King with the new, but very similar, cams.
There was no excessive noise and my max torgue came in very
close to the original.
I'm going to
take it back after I put add 100 miles. I'll report back.
This piece was final edited by Bruce Snyder who owns
an '03 H-D. He made the following comment about his
experience with cam drives:
Here's my shoes after only 12,000 miles.
Just out of curiosity, what kind of shape were your tensioner
shoes in? Mine were still fully intact at 57K, although the inner
shoe would've probably been toast in another couple thousand.
But a friend of mine had a shoe grenade and take out the oil
pump on his RK at 42K. I can send you a pic of what my shoes
looked like if you're curious. Seems to be a crap shoot on how
long they'll last - I know another fellow who's racked up over
60K on his '03 Duece with no issues.
Here's Bruce's shoes. Note that all the wear and tear to
these puppies could have clogged an oil passage.
Enjoy the ride. My local indy installed Andrews 26Gs in my
'03 FXST a year ago (a tad milder than your S&S set) and I love