here`s a grain of truth in every cliché, but in some, like

T
here’s a grain of truth in every cliché, but in some,
like “There’s no replacement for displacement,”
there are enough grains to fill a silo. That saying is
especially true when you’re riding a bagger two-up, or
towing a trailer. Tom Chapman of North County Customs had a customer, Rick Wright, who does both with
his 2002 FLH. So Mr. Wright asked Chapman to give
his ride more poke from its Twin Cam. The solution
was to turn to the Delkron catalog for a set of 107-inch
cylinders and matching heads.
The Delkron 107 cylinders are larger than stock, so the crankcases must be stripped and
bored. Tom Chapman uses a JIMS fixture and tool to do the job.
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The cylinders have a 4.125-inch
bore, which necessitates removing
the engine, stripping the crankcases, and machining the cylinder
spigots to accommodate the larger
sleeves. This is a fairly straightforward procedure, except that the
process cuts into the thread area of
a stud fitted to the crankcase between the cylinders. The solution is
simple: drill the stud hole all the
way through to the outside of the
crankcase and fit an external
through-bolt in place of the stud.
It’s easy to do when the crankcases
are already disassembled.
The Delkron kit uses the stock
cylinder-stud spacing, so all you
have to do is take the studs out
when you machine the cases then
put them back before you install the
cylinders. The aluminum Delkron
jugs have iron liners and come with
Ross forged racing pistons, pins and
keepers, and the whole package is
sealed with Cometic gaskets.
Chapman topped the Delkron
cylinders with a pair of Delkron
heads; the cylinders and heads can
be bought as a kit, or separately.
The Delkron heads come assembled,
with 2-inch intake and 1.625-inch
exhaust valves, a custom intake
manifold, and Cometic gaskets.
Chapman also went for a set of
Delkron’s two-piece rocker boxes,
which are half an inch shorter than
stock for easy installation and removal into the frame. They also
have more spacious valve-spring
pockets that allow room for high-lift
cams and springs.
IronWorks August 2009
The “New” Delkron
here’s a new kid in town—the “New”
Delkron, Inc. Here’s the deal: Delkron
and HSE Inc. have merged their resources to become what is essentially a
new Delkron Inc. Delkron’s Steve
Swarthout and Shawn Macnamara have
teamed with experienced engine builders
and designers Steve “Posie” Pfaff, Frank
Aliano, and Mike Kemper, formerly known
as Hay Seed Engineering Inc., who bring
an accumulated 100+ years of engine-related knowledge to the table. This includes working with clients such as
Harley-Davidson and Indian, plus spearheading individual successes at P&M2
Powertrain LTD in Dillsburg, Pennsylvania
and Blackhawk Motor Works in Palm Bay,
Florida.
Revising Delkron this way enables the
company to expand its product line, tighten quality control and offer a long list of
machine-shop options for its customers.
Plans also include a program for remanufacturing many brands of American-made
V-twins, including single-cam Harleys.
T
Boring the cases is a job for an experienced machine shop with the tools and the
know-how to do it right; one slip and your cases are paperweights.
The bike was already equipped
with a Power Commander; a good
thing, says Chapman, because an
upgrade of this kind should never
be done without remapping the fuel
injection. “I recommend putting it
on a dyno and mapping it every 250
RPM,” says Chapman, who farmed
that job out to Temecula Motorcycle
Service. Chapman also equipped it
with a D&D collector exhaust.
The Delkron big-bore kit uses the
stock crank, and therefore
the stock stroke, which results in an engine that doesn’t vibrate as much as some
strokers. “When you keep
the stock stroke you don’t
have the piston speed a
long-stroke motor does.
This is a very good set-up
for someone who puts a lot
of miles on in a day.”
Chapman is pleased with
Resource
Delkron, Inc., Bedford, Ohio
440-786-8820
www.delkron-mfg.com
continued
IronWorks August 2009
63
ironworksmag.com
the results of the big-bore install.
“We set this motor up with a 9.8:1
compression ratio,” he says. “This
bike is in a conservative state of
tune and produces 115 horsepower
and 115 ft.-lbs. of torque. It makes
very early power, starts easily, and
runs on pump gas.”
When it comes to Delkron prod-
The Delkron cylinders are made of high-quality aluminum with iron liners. They come with a
black or natural finish, and look, in Chapman’s words, “like jewelry.”
Boring the cases for the new
cylinders affects the crossover
stud threads. The solution is to
completely bore the hole and
use an external through-bolt.
Delkron uses Ross forged racing pistons in
its cylinder kits. Rings, pins, keepers, and
gaskets are included. This engine’s compression ratio was set at 9.8:1.
Chapman topped the Delkron cylinders
with Delkron heads. The assembled heads
have stainless valves, upgraded springs,
and larger ports for better flow.
Reader Service No. 34
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IronWorks August 2009
ironworksmag.com
ucts in general, Chapman is equally
satisfied. “I use the term jewelry,”
he says, referring to his impression
of Delkron’s quality. “The fit and
finish of this kit are impeccable. The
pictures don’t do it justice.”
Neither does simply reading
about it, either. Unless you ride it,
you just can’t feel the full impact of
a top-end kit that produces tripledigit horsepower and torque numbers, yet starts and runs like a stock
engine. The Delkron 107 kit proves
another cliché—there’s no substitute
for cubic inches.
Chapman calls Cometic gaskets “the best
gaskets out there.” They come standard in
Delkron big-bore kits like this 107”
package.
Reader Service No. 35
Resources
Delkron
Bedford, Ohio
866-335-5766
www.delkron-mfg.com
North County Customs
Fullerton, California
760-728-5757
www.northcountycustoms.com
Performance Techniques
Orange, California
714-612-9060
www.hardyheads.com
D&D Performance Exhaust
Fort Worth, Texas
817-834-0996
www.dandexhaust.com
Temecula Motorcycle Service
Temecula, California
951-296-9377
www.temeculamotorcycle
service.com
Reader Service No. 36
IronWorks August 2009
65