Bennett’s Performance Final, Maybe

Bennett’s Performance touts being the performance test bed for all-things big twin performance and handling in Long Beach, California. The team is also very involved in Bonneville Land Speed Record efforts. Unless the California Air Resources Board decides to shut down every California custom or performance shop, they will be burning rods, turning lathes, and twisting wrenches until they die.

I say, “They,” and I’m referring to Eric Bennett, the boss, and his longtime mechanic and Dad, Bob. Other technicians come and go. Plus, next-door are the men, including Jerry Branch, and John O’Keefe, who are the masters of the flow bench and headwork at the Branch O’Keefe machine shop.

All shops big and small in California live in fear of being shut down. But let’s not go there. For a few minutes let’s pretend that freedom rings in this country and our political structure loves folks who build anything from hot rods to custom motorcycles. They even support the notion that loud pipes saves lives, because it’s true. They love it that guys don’t beat their wives or do drugs, that they learn how to work with their hands and create something one-off, which they can ride to work or to Sturgis with pride. Am I dreaming or what?

Eric recently came across this 2004 Dyna and decided to research every performance resource and build himself the best hot rod Dyna on the planet, as a test project for anything performance, for Twin-Cams. He did, and we followed the process on, and this is the third and last stellar episode. But wait, their could be more, according to Eric’s assessment at this point.

“I need to change the shocks,” Eric said. “They are too low and shifting the weight to the rear. I need to tighten the handling.”

Eric was pushing is Dyna onto his shop dyno as we strolled into Bennett’s Performance, a very clean and well-organized shop, a couple of weeks ago. “I wanted to dyno it one final time without a rev limiter,” he said and discovered a dyno malady. The battery was low. At about 5500 rpms the dyno results didn’t indicate a smooth transition through the gears, but jumpy results. He was dying to try again, but we were forced to take a break.


“We’ve run across jumpy dyno results with other rubbermounted bikes, specifically Dynas,” Eric said. With the dyno fixed he removed his air cleaner and backing plate to allow the carb to float. Then he changed his 48 mm Mikuni main jet to the next larger size, for more fuel, and he retarded his timing one notch. He pulled it twice on the dyno and was proud to watch it jump from 117 hp, and to 119 hp, and 121 pounds of Torque. The power range was perfect for street use.

Eric now has 1978 miles on the bike since he rebuilt and upgraded the engine from 88 inches to 106. Shortly after the bike was completed and running, his dyno pulls indicated 112 hp and 119 pounds of torque, then 116 hp and 118 pounds of torque with a carb change, more miles and tuning. 


 Our discussion shifted back to handling. “At 100 it starts to wiggle,” Eric said, “There’s too much weight on the back.” He plans to install 14-inch Ohlins. Today, the lower badder look is slipping away for the jacked, terrific suspension, badass, dirt bike, café racer, SOA, go fast appearance.

We discussed the new CCE stiffer rubbermounts for Dynas, which might do the trick. “I still won’t be able to dial-in the handling as well as FXRS, like the Unknown Industry guys,” Eric said. “With my handling issues, they pulled away at just over 100 mph. The front feels fine, but I haven’t decided what to do with my number plate. Newer Dynas have additional gussets, but nothing like the FXR, period!”

He plans to black out the wheels and add Michelin tires, but he loves this engine configuration. “It’s perfect,” Eric said. “I didn’t need to machine the cases or crank up the compression. The cam isn’t radical, and I could run stock cylinders.” Jerry Branch told Eric that engines are like a combination lock. One number off and the system doesn’t work.

He’s currently looking for an ’06 or ’07 Dyna 17-inch rear wheel, and he will run a 160 tire. “It still gets 42 mpg. Reaching more than one horsepower per cubic inch with a naturally aspirated engine. It’s impressive.”

The S&S lower end contains a 4.5-inch stroke with 3 7/8-inch S&S pistons. Eric blocked the Mikuni carb out one inch to allow the air and fuel to atomize more before it reached the intake valves. “It’s a smoother delivery to the chambers,” Eric said. “We were lucky to score a set of Dave Thew heads designed for monster JIMS 116-inch motors by the Branch/O’Keefe team. This combination with 2.02 intake and 1.610 exhaust valves, and some slight porting, coupled with a Redshift .647 lift cam, and 11.5:1 compression gave Dave Thew 132 ass-kicking horsepower and 132 pounds of torque.

Dave’s bike with fat tanks and beach bars could not be beat at the drags.

I spoke to Eric’s dad who talked of his Bonneville bikes and going after a 167 mph record. Eric was the rider. “We couldn’t get over 161, but then I learned about aerodynamics. I gained 9 mph by moving the pipes inboard. We gained another 5 mph when Eric shifted his riding position and tucked one foot behind the primary.” They grabbed a record.

So, you can tell by the smell of go-fast, the posters of Burt Munro on the wall, and the Bennett record next to the counter, that this group is all about motorcycles and folks who ride hard and fast. Hang on for the next report. Extreme Bennett’s Performance Tech Chart
Regular Stuff
Owner: Eric BennettBike
Name: Brute
City/State: Signal Hill Ca
Builder: Eric BennettCity/state: Signal Hill, CA
Company Info: Bennett’s Performance Inc.

Address: 1940 Freeman Ave,Signal Hill Ca, 90755

Phone: 562 498 1819
Fabrication: Bennett’s
Manufacturing: Harley-Davidson
Welding: me
Machining: me
Year: 2004
Make: Custom
Model: Twin cam
Displacement: 106 cubic inches
Builder or Rebuilder: Eric Bennett
Cases: H-D
Case finish: Black
Barrels: H-D turned round By Branch
Bore: 3 7/8-inch
Pistons: S & S
Barrel finish: stock
Lower end: S&S
Stroke: 4 ½-inch
Rods: S&S
Heads: Branch #4 Dave Thew mods
Head finish: Stock
Valves and springs: AV&V
Pushrods: S&S
Cams: 585 S&S
Lifters: S&S
Carburetion: Mikuni 48 mm modified by Bennett’s
Air cleaner: S&S muscle
Exhaust: D & D Bob cat modified by Bennett’s
Mufflers: D&D Bob Cat

Year: 2004
Make: H-D
Gear configuration: Stock 5-speed with wpc treatment
Primary: stock
Clutch: Rivera Primo Pro Clutch
Final drive: Stock
Year: 2004
Builder: H-D
Style or Model: Dyna

Front End
Make: H-D Speed Merchant
Model: 2004 Dyna sport
Year: 2004
Length: Stock
Mods: Speed Merchant Trees, risers, grips
Sheet metal
Tanks: H-D
Fenders: stock
Panels: stock
Oil tank: factory
Sheet metal: nicked Black
Molding: none
Graphics: Nothing yet, maybe pinstriping
Type: Factory
Pinstriping: Maybe George the Wild Brush
Make: H-D
Size: 19-inch
Brake calipers: Brembo
FrontBrake rotor(s): Lyndall
Tire: Metzler

Make: H-D

Size: 16-inchBrake calipers: Stock
Brake rotor: Lyndall
Pulley: H-D

Tire: Dunlop
Foot controls: Factory stock Master cylinder: H-D
Brake lines: Barnett
Handlebar controls: Factory Clutch
Cable: Barnett
Brake Lines: Barnett
Shifting: Stock
Kickstand: Factory

Ignition: Dyna twin cam 88
Ignition switch: H-D
Coils: H-D
Regulator: Stock
Charging: Spyke
Starter: H-D
Wiring: Mostly stock
Headlight: Alloy Art
Taillight: Alloy Art
What’s Left
Seat: Le Pera
Mirror(s): Speed Merchant
Gas caps: Stock
Handlebars: Todd’s Cycle
Grips: Speed merchant
Pegs: Speed Merchant
Oil filter: Hi Flo
Oil cooler: Jag
Throttle cables: Barnett
Fasteners: Unbrako
Specialty items: Custom Number Plate fabricated by Brandon at Speed Merchant
Credits: S&S Cycle, Alloy Art, Speed Merchant, Mikuni Carbs, Rivera Primo, Bikernet, Lyndall Racing Brakes.
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