Bennett's Performance - Sweet Tracker | Big Bore Hop-Up, Part Two

Big Bore Hop Up Part Two Mikuni Carburetor

2 The Mikuni HSR42 carburetor is a very easy installation process. Since the stock CV carb was already removed, Eric hooked up the stock choke with Mikuni’s starter nut (A), spring (B), and plunger (C) to work with the stock choke cable and knob. Once that was done…

2 The Mikuni HSR42 carburetor is a very easy installation process. Since the stock CV car

With a new carburetor and ignition, I had to complete the trifecta with the right exhaust pipe. SuperTrapp’s Sportster 2-into-2 XR Style System ($795) was the only pipe I wanted because it pays a well-deserved homage to the coolest motorcycle » on the planet in my opinion, the XR-750. The high pipe style and brilliant stainless steel construction exquisiteness will not only add a visual appeal to the Sweet Tracker, but a nice boost in power as well. What else could a guy want? The XR Style 2-into-2 pipes also include SuperTrapp’s award-winning disc tuning technology, which affects how the exhaust system performs. How many discs you use depends on what you’ve got going on in the engine components department, and also how loud you want your pipes to be.

With the installation of all-new engine components, I didn’t want to fill the oil bag with any old type of lube. Amsoil recently introduced its Break-In Oil ($7.15 per quart), which is loaded with zinc and phosphorous additives to aid piston ring seating during initial start-up and break-in-mileage accumulation. Because it’s formulated with no-friction modifiers, Amsoil’s Break-in Oil flattens sharp peaks on newly honed » cylinder walls, resulting in a larger surface area for the ring face to seat against creating a dynamic seal that claims to increase horsepower, compression, and torque.

3 Eric routed the throttle/idle cables to the Mikuni carb to ensure a proper fit.

We asked motorcycle performance guru, Eric Bennett, from Bennett’s Performance in Signal Hill, California, if he’d give us a hand putting Humpty Dumpty back together again. Lucky for me, he obliged. Eric can handle any and all Harley performance needs, and he’s an all-around good guy. HB

Big Bore Hop Up Part Two Mikuni Backplate

4 Eric then mounted the Mikuni backplate adapter and O-ring to the stock air cleaner assembly backplate with the provided hardware. Note: Mikuni makes kits that include a new backplate with air filter and air cleaner cover, but I dig the stock “ham can” air cleaner, which is being used here.

5 Moving on to installing the Daytona Twin Tec ignition setup, Eric never reinstalled the stock ignition after installing the cams in last month’s installment because we’d be installing the new ignition here. The new ignition installs into the cam nose cone shown here.
5 Moving on to installing the Daytona Twin Tec ignition setup, Eric never reinstalled the
6 Eric wrapped the ignition wiring with electrical tape in order to feed it through the bottom of the gear case to link up to the new ignition coil that will be installed later. You may be wondering why the ignition installs sideways, but that’s how the cookie crumbles for this particular model. Do not force the ignition module in place. Be very conscientious of the black plastic Hall effect sensors at the bottom of the unit when installing. If they get damaged, you’re screwed.
6 Eric wrapped the ignition wiring with electrical tape in order to feed it through the b
7 After routing the white/black, purple/white, green/gray, and pink wires from the new ignition unit to the factory ignition wiring Deutsch connector, Eric routed the remaining blue and brown wires to the supplied Daytona Twin Tec two-pin connector. After plugging the wires into the connectors, he routed them up to where the new ignition coil would be installed.
7 After routing the white/black, purple/white, green/gray, and pink wires from the new ig

8 Eric removed the stock dual-fire ignition coil from under the backbone of the frame. He needed to install the stock key ignition switch to the new ignition coil.
8 Eric removed the stock dual-fire ignition coil from under the backbone of the frame. He
9 The stock two-terminal ignition coil (left) is what’s known as a dual-fire ignition coil. Daytona Twin Tec’s three-terminal single-fire ignition coil (right) eliminates backfire and enhances idle quality. The single-fire ignition uses separate coil windings and electronics to fire each spark plug independently. Spark firing occurs only on the compression stroke. With a dual-fire coil, when the rear cylinder is fired on the compression stroke, the front cylinder is on the exhaust stroke. But when the front cylinder is fired on the compression stroke, the rear cylinder is already on the intake stroke. Under some conditions, a combustible mixture may exist in the rear cylinder at this point and the wasted spark causes a backfire through the carburetor. It was highly recommended that I use Daytona Twin Tec’s ignition setup to compensate for the performance engine mods and Mikuni carburetor.
9 The stock two-terminal ignition coil (left) is what’s known as a dual-fire ignition coi
10 Eric installed the single-fire coil and crimped on the provided ring terminals to the ignition wiring and hooked them up to the coil.
10 Eric installed the single-fire coil and crimped on the provided ring terminals to the

11 Next, Eric test-fit the plug wire length from the spark plugs to the coil and measured how much wire would be needed.
11 Next, Eric test-fit the plug wire length from the spark plugs to the coil and measured
12 After figuring out the correct length, Eric snipped the plug wires for each cylinder and routed them up to the ignition coil and plugged them in. Installation for the Daytona Twin-Tec components was completed at this time.
12 After figuring out the correct length, Eric snipped the plug wires for each cylinder a
13 Moving on to the SuperTrapp exhaust installation, Eric stuffed the exhaust gaskets into the exhaust ports of the re-worked heads…
13 Moving on to the SuperTrapp exhaust installation, Eric stuffed the exhaust gaskets int

14 …then installed the stock exhaust pipe flanges onto the new pipes with the stock circlips.
14 …then installed the stock exhaust pipe flanges onto the new pipes with the stock circl
15 After mounting the front head pipe to the front cylinder first, then the rear head pipe, installation was nearing completion.
15 After mounting the front head pipe to the front cylinder first, then the rear head pip
16 Eric slid the mufflers on with the provided clamps one at a time. Be sure to test-fit everything before tightening the hose clamps.
16 Eric slid the mufflers on with the provided clamps one at a time. Be sure to test-fit

17 The SuperTrapp mufflers mount to the outside of the right shock with a provided bracket. I had to find some spacers to prevent the bracket from rubbing against the shock body. After finding the right spacers, the shock bolt was re-installed.
17 The SuperTrapp mufflers mount to the outside of the right shock with a provided bracke
18 To cinch the mufflers up there’s a hole at the bottom of the same shock mounting bracket where Eric installed the provided hardware to finish up the exhaust pipe installation.
18 To cinch the mufflers up there’s a hole at the bottom of the same shock mounting brack
19 The last step with the SuperTrapp pipe installation was plugging in SuperTrapp’s tunable discs. The technology allows users to fine-tune exhaust note preference as well as play with torque output in the low, mid, and high ranges. The discs come with anti-seize and a provided Allen wrench for installation.
19 The last step with the SuperTrapp pipe installation was plugging in SuperTrapp’s tunab

20 This specific kit included 24 discs (12 for each muffler), and Eric and I decided to install all 12 on each and decide whether or not to remove discs after some break-in miles.
20 This specific kit included 24 discs (12 for each muffler), and Eric and I decided to i
21 Back to the air cleaner installation since Eric wanted to install the SuperTrapp pipes first to check for clearance issues. Once everything looked up to snuff, he installed the Mikuni backplate adapter and O-ring along with the air filter mounting hardware to the stock backplate with blue threadlocker.
21 Back to the air cleaner installation since Eric wanted to install the SuperTrapp pipes
22 The stock breather bolts were utilized for this application to get the backing plate installed to the cylinder heads…
22 The stock breather bolts were utilized for this application to get the backing plate i

23 …and the K&N filter and stock “ham can” air cleaner cover were the last to be installed. That about does it for the installation of all the engine components for the Sweet Tracker. After everything was buttoned up, Eric started the bike and adjusted the Daytona Twin Tec ignition timing. He then played around with the adjustable idle mixture dial on the Mikuni carb until everything was running tip-top. Per Eric’s recommendations, I was instructed to put about 50 break-in miles on the bike, change the oil with Amsoil’s 20W-50 Synthetic Motor Oil, and also change the filter with the K&N oil filter that I scotch-brited. Then after about 500-or-so miles on the bike it would be ready for some runs on the dyno. Check back next issue when we reveal what the bike pulled on the dyno.

Source:

Amsoil (800) 956-5695
amsoil.com

Bennett’s Performance
(562) 498-1819
bennettsperformanceinc.com

Daytona Twin Tec
(386) 304-0700
daytona-twintec.com

Harley-Davidson
Contact your local dealer
harley-davidson.com

K&N Engineering
(800) 858-3333
knfilters.com

Mikuni
(818) 885-1242
mikunipower.com

Revolution Performance
(920) 892-2109
revperf.com

SuperTrapp
(216) 265-8400
supertrapp.com

hot.bike@sorc.com