After 10 years of solid performance out of his 2002 Road King, our friend, Oscar, was ready for more power. He’d done the normal upgrades such as pipes and air cleaner, but now the 88ci mill just wasn’t putting down the horsepower and torque he desired. Over the 10 years Oscar has owned his King, Harley has continued to up the engine displacement of its OE models from 88 ci to 96 ci and now surpassing the century mark with the 103s found in the latest models.
Of course Oscar’s first thought was to upgrade to a brand-new Harley with more power, a better frame, and an extra gear for highway cruising. But then a new bike would mean new payments and that didn’t sit too well with him. So after weighing his options, he decided the easiest way to get more power would be to bump up his displacement with a big-bore kit from S&S. Just by swapping out the stock cylinders and pistons for a set of 3.972-inch bore cylinders and pistons, he could nearly hit the triple-digit displacement mark, arriving at 97ci. Going this route would be a relatively easy bolt-on affair and wouldn’t require splitting and boring the crankcases.
Once the bike was at his local dealership, Los Angeles Harley-Davidson of Anaheim, and the top-end was torn down, the service tech, Kevin, noticed a problem. After nearly 60,000 miles, Oscar’s flywheels had taken a turn for the worse and had shifted and come out of true. As he cycled the flywheel assembly, Kevin noticed that they were beginning to bind up. Fortunately the issue hadn’t gotten too severe yet and hadn’t caused any internal damage, or worse, left Oscar stranded on the side of the road somewhere.
At this point, Oscar considered just having the dealership pack the engine up and ship it to Harley to go through the company’s remanufacturing program. While this would result in a factory-fresh engine, it wouldn’t solve his need for more power; he’d still be sitting at the original 88ci displacement and relative performance the bike came with. Not sure where to go next, Oscar hit us up for advice, and in turn we went straight to the source and asked S&S its opinion.
After some investigating and discussing Oscar’s dilemma with his collogues, S&S Marketing Manager Bruce Tessmer came back with a solution: ditch the stock flywheel assembly and shove one of S&S’s 4-3/8-inch stroke flywheels in between the cases. With the same stroke as that found in Harley’s late-model 96ci and 103ci bikes, S&S stated that its 4-3/8-inch flywheel would fit into the Oscar’s 2002 crankcase. Best of all, the flywheel assembly would squeeze in without having to machine the crankcases—like the big bore kit, it would essentially be a pressed-in/bolt-in affair. The combination of the big bore kit and the stroker flywheel would put the bike’s displacement to 106ci, past Harley’s late model OEs displacement. To help squeeze even more power out of the big-bore/stroker setup, S&S recommended adding a set of its 585 Easy Start cams, 58mm Single Bore Throttle Body kit, 58mm manifold, and one of its new Stealth/AirStream Air Cleaner kits. Oscar took the advice and added to his order some S&S Quickee Pushrods and tubes and hydraulic tappets. To dial everything in and make sure the bike stays in tune, he also got one of Dynojet’s new Power Vision EFI modules. The combination of all these components and the huge jump in displacement should result in some great horsepower and torque numbers, but more importantly for Oscar, the end result will be like riding a completely new and exciting bike.
This is a pretty involved hop-up so we are going to break it up into a couple articles over the next few issues. Follow along as we show you some of the main components from S&S that will be used to rebuild this engine.
02 The flywheel assembly comes fully assembled, dynamically balanced, and trued. Unlike the 1.671-inch crankpin found in H-D’s 88ci engines, S&S uses a smaller 1-1/2-inch-diameter crankpin. According to S&S, a smaller crankpin allows for the use of replaceable bearing races in the lower end of the rods. The smaller crankpin also equates to less weight while providing more clearance when stepping up to larger flywheel stroke. Through its experience with nitro drag race engines, S&S has found that the smaller crankpin is more than capable of handling the stresses associated with high-performance engines.
03 These are the cylinders and pistons that come with S&S’s 106ci Big Bore kit ($749.95) that will be used with the flywheel assembly. S&S offers these kits for 88ci and 96ci engines. With no crankcase boring required, owners of 88ci bikes can bump up to 97ci, while those that have the 96ci engines can step up to 106ci just by swapping their stock setup for these cylinders and pistons. The cylinders feature a high-strength liner material, and with a 3.97-inch bore, this is the largest diameter S&S is willing to go with these cylinders and still feel confident about their longevity and durability. While the OE cylinders can be bored to this same diameter, S&S isn’t sure the stock liner and spigot material is strong enough to hold up. The cylinders are available in silver or black powdercoat to match OE engine finishes.
04 The 3.927-inch forged coated pistons are flat top pistons that feature enlarged valve pocket recesses for oversize valves and higher lift cams, like the 585s that will be installed.
05 S&S recently came out with its new Stealth Air Cleaner which features a high-flow air filter combined with an air directional stinger cone over the top of the filter that directs air flow to the center of the radiused inlet of the back plate. The design helps streamline air directly into the carb/throttle body. You can use the traditional S&S teardrop air cleaner cover or S&S offers several other covers like the new AirStream cover, which is similar to the teardrop but features meshed vents. S&S offers the Stealth Air Cleaner and Air Stream cover as kits ($265.95) in either jet black or chrome.
06 Here’s the throttle body kit ($824), manifold ($134.95), Quickee Pushrod kit ($224.95) hydraulic tappets ($259.95), and Easy Start 585 cam kit ($367.95) Oscar got for his bike.
07 This 58mm throttle body combined with the Stealth/AirStream Air Cleaner kit should provide plenty of air to generate good power. Sold as a complete kit, the throttle body comes with larger fuel injectors, a fuel rail, harness adapters, and all necessary hardware, gaskets, and hoses.
08 Introduced a few years back, the Easy Start cams feature a spring-loaded compression release built into the heel of the exhaust cam lobes at the point where the valve would normally be fully closed. The raised lobe of the compression release holds the exhaust valve slightly open at cranking speed, which releases some of the compression making it easier to turn the engine over and relieves stress on the battery and starter. According to S&S the 585s are designed for larger displacement engines to deliver strong horsepower and torque through the 2,500-5,500-rpm range.
09 When we caught up with Kevin he had already taken the primary off, unbolted the engine case from the transmission, and was pulling the case out of the frame.
10 With the lower end on a work bench, Kevin removed all the case bolts, then bolted a JIMS crank assembly removal tool to the left case half.
11 As he turned the center screw of the removal tool the case slowly separated.
12 He was then able to remove the left case half exposing the left side of the flywheel.
15 The right side of the case was then taken over to the press so that the old right-side main bearing could be pressed out.
16 With the right-side main bearing out of the case, Kevin cleaned the case half and then checked the new 585 cams for clearance. One of the camshafts was placed inside the camshft bearing and Kevin rotated the camshaft to see if it would hit the inside of the case. As you can see, there was minimal clearance between the camshaft lobe and the lip of the case where the main bearing resides (arrow). There was also minimal clearance at the top of the cam’s rotation on the underside of the tappet housing. These areas needed to be addressed before moving further.
17 This Twin Cam Relief Tool from Zippers will precisely clearance the inside of the cam chest for the larger cams. The tool features cutter diameter and depth adjustment for precise control of material removal. The cam bearing supports the bottom of the spindle, the cutting bit is the blue piece against the main bearing housing. Kevin made sure to tape up any exposed areas and holes to keep bits of metal from entering the engine once reassembled.
18 After measuring the cams and adjusting the relief tool in accordance with the cam and the amount of material to be removed, Kevin bolted the support plate to the case and attached a drill to the cutting tool. He then slowly let the drill rev as he gradually fed the cutting tool into the case.
19 Here you can see the tool spinning around and gradually removing bits of metal from the case.
20 After a few minutes, Kevin removed the cutting tool and checked the cam clearance. As you can see, there is now much more room between the top of the lobe and lip of the main bearing housing (arrow).
21 The process was repeated for the other cam as well. The tool provides a very clean and precise cut.
22 Here’s a look at the underside of the tappet housing where the tool clearanced the case as well. At this point Kevin thoroughly cleaned and dried the case. We will leave off here. Be sure to check back next issue as we continue to follow the build-up of Oscar’s engine.
Los Angles Harley-Davidson of Anaheim
losangelesharleydavidsonofanaheim.com | (714) 871-6563
sscycle.com | (866) 244-2673