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Making the Road King RompAnd It Still Looks Stock From the February, 2009 issue of Hot Bike
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You've heard it before: Speed is addictive. It's one of those things that you just can't seem to get enough of. Those were our exact thoughts while we eyed our colleague's '98 Road King fuelie. With the exception of the exhaust system and the Screaming Eagle cam, the motorcycle was the same as it was the day it left the factory. We wanted to take this 80-inch fuel-injected motor and give it the performance that would equal one of today's 95-inch kits. We wanted to gain significant horsepower and torque without increasing displacement. Considering this, we would need the help of someone well known for making big power without sacrificing durability - which a well-ridden Road King needs. One of our requirements for the Road King was to have the bike remain as stock-looking as possible. We wanted to have a real sleeper on our hands -- a bike capable of holding its own at a light and comfortable riding two-up on a hill. Our search landed us at Patrick Racing in Garden Grove, California. Nigel Patrick has been hot-rodding motorcycle engines for the last 25 years. His specialty these days are V-twin powerplants. We conveyed our thoughts about the hop-up we were planning on doing. After a few moments, he came back to us with the suggestion of adding a Dynojet Power Commander II Hooter 2-into-2 pipe and doing a little of Patrick Racing's CNC porting of the existing heads, J&E pistons, and a 0.560-inch lift Patrick Racing cam. We chose this exhaust to retain the almost stock look of the bike. If we had gone with a 2-into-1 pipe, we would increase our dyno numbers around four or five horsepower. Nigel figured that by making those modifications, the motor would give us the horsepower gains we were looking for without pulling the motor from the bike to facilitate additional stroke. Nigel's plan would save us time and allow us to keep more of our hard-earned cash in our pockets. We dropped off the bike and Nigel placed us in the capable hands of one of his top men, Doc. The Road King was rolled onto a lift and Doc tore into it.  1: By the time we returned...  1: By the time we returned the following morning, it was apparent that Doc had been busy, the bike was disassembled and he was getting set up to start Patrick's CNC porting procedure.  2: The original valve seats...  2: The original valve seats are machined out of the heads, and a new seating surface is milled into the heads. In order to install the new seats, the heads are heated with a torch, then the new seats are driven into the heads. The seats have 0.006-inch interference fit in the head, ensuring a good, tight fit to minimize potential problems down the road.  3: The key to Patrick Racing's...  3: The key to Patrick Racing's head modification is the procedure it developed to allow the heads to be ported exactly the same way, each time for a particular head design. After many hours of machining and flow bench testing, a set of heads is carefully measured, and all that information is digitized and loaded into the milling machine. Here, one of our heads is bolted to a five-axis rotary table waiting for the mill to start running the program necessary for this style of head.  4: After the head has been...  4: After the head has been ported and the valve seats machined, they are treated to the final step of the porting procedure. Brian uses a strip of 80-grit emery cloth inserted into his die grinder to form a flapper. This flapper is then used to smooth out all the surfaces from the intake port into the combustion chamber right on through the exhaust port. The surface is smoothed out to ensure the fuel and exhaust move through the head as efficiently as possible. Although the surface is smooth, it is not polished. By keeping the surface finish slightly rough, a certain amount of turbulence is created to ensure top performance.  5: A comparison of our two...  5: A comparison of our two heads: one ported, while the other remained stock awaiting its turn on the mill, seat cutter, and Brian's die grinder.  6: Our head awaiting installation...  6: Our head awaiting installation of new, larger valves. The stock valves were 1.850-inch on the intake and 1.565-inch on the exhaust compared to our new valve dimensions of 1.940-inch intake and 1.625-inch on the exhaust. After the head has been cleaned with an ultrasonic parts cleaner, Doc test-fits the valves in the seats. Once he is satisfied with the fit...  7: ...the valves are lapped...  7: ...the valves are lapped into the seats one at a time. After lapping, Doc visually inspects the surface of the seat to verify that the valve makes proper contact all the way around. The lapping compound is then cleaned from the surface, and the head is ready for assembly.  8: A valvespring compressor...  8: A valvespring compressor is cinched down in a bench vise and Doc installs the valves by adding a valve stem seal, a bottom collar, a high-lift spring kit, a titanium top collar, and a set of keepers.  9: A set of J&E forged pistons...  9: A set of J&E forged pistons will replace the stock pistons. The new domed pistons will add to our compression numbers. The stock 80-incher has a compression ratio of about 8.4:1. Our new setup is designed to bring the number up to 10.1:1. The J&Es have proven their performance when paired with Patrick's CNC ported heads.  10: Here's a good look at...  10: Here's a good look at the Road King's Screaming Eagle camshaft on the left compared to the new Patrick Racing camshaft. The new camshaft has 0.560-inch of lift as well as longer duration than the one it replaces. This will ensure that the valves will open far enough and stay open long enough to let the motor really flex its muscle.  11: Doc measures the cam that...  11: Doc measures the cam that just came out of the bike. That measurement is compared to the measurement of the new cam. They are within 0.001-inch. That means no additional shimming will be needed to keep the amount of endplay within specs. After the cam is installed and the nose cone is replaced, Doc will measure the cam endplay to double-check that it is indeed in specs. The total amount of endplay in this case worked out to 0.0015-inch well within HD's limits of 0.050-inch.  12: The camshaft and cam gear...  12: The camshaft and cam gear thrust washer are ready to be installed. Note the aluminum blocks being held up by some wooden shims. The aluminum pieces have magnets inserted into them. These magnets hold the lifters up and out of the way to facilitate installation of the camshaft. The wooden shims are used to ensure that the lifters are raised high enough during the installation process.  13: It is important to line...  13: It is important to line up the timing marks on the camshaft, the breather gear, and the pinion gear. The timing marks are denoted by a small mark or a line on the gear near the root of the gear teeth.  14: The cylinders have been...  14: The cylinders have been machined for the new pistons to fit, with this done, Doc hones the cylinders to give the new rings a proper surface with which to seat against.  15: After both cylinders have...  15: After both cylinders have been honed and thoroughly cleaned, base gaskets are installed and a piston is attached to the connecting rod sans rings. The cylinder is then slid over the studs and snugged down. Doc then takes out his depth micrometer and measures from the top of the cylinder down the top of the piston. This is known as measuring the deck height. The point of this exercise is to ensure that when the piston is at top dead center, it is as close to the top edge of the cylinder as possible without going above the top of the cylinder. The domed portion of the piston projects above the top of the cylinder, but the circumference of the piston must remain below.  16: Nigel chucks up one of...  16: Nigel chucks up one of the cylinders in the lathe and machines 0.030-inch from the base. Once the material has been removed, the piston will at TDC be even with the top of the cylinder. Keeping the piston close to the top of the cylinder is vital in keeping the motor from knocking.  17: Once Doc is satisfied...  17: Once Doc is satisfied that he has the proper deck height, he fits the rings in the cylinders and checks for proper ring gap: ours measured 0.010-inch. The rings were then fit to the pistons. The pistons were installed on the connecting rods, and the cylinders were slid down over the pistons with the help of a ring compressor. The heads were then set into place and torqued down. Here the rear rocker box has been installed while the front one is being buttoned up.  18: It's now time to adjust...  18: It's now time to adjust the adjustable pushrods. Since our lifters are not new and have been pumped up with oil, they will need to be bled down. This is accomplished by rotating the piston to bottom dead center, then lengthening the pushrod until it contacts both the lifter and the rocker. Once contact is made, the pushrod is opened up an additional 2.4 turns. This works out to approximately 0.100-inch in our case. All pushrods do not use the same thread pitch, so make sure to check what pitch yours has and then calculate the number of turns from there. After you have adjusted the first pushrod, wait until the lifter has bled down. To verify this, place the pushrod between your thumb and forefinger and try to spin the pushrod between your fingers. If you can spin it, the pressure has been bled down. You can now move on to the next pushrod... and the next, and the next.  19: Doc mounts the Power Commander...  19: Doc mounts the Power Commander II inside the cover on the primary side of the bike. The Dynojet Power Commander II is an electronic device that allows a mechanic to re-program the fuel injection by means of an external computer. The Power Commander II is connected to the motorcycle's ECU and intercepts signals from sensors that are tied to the ECU. The Power Commander II takes those signals, and based on the map that is programmed into it, makes changes to the fuel delivery system as well as the timing. The map that has been installed at Patrick racing could be copied to a disk, and then installed on another bike without having to figure out a new map.  20: The Power Commander II...  20: The Power Commander II on an injected motor is like having a large selection of different-sized jets for a carbureted motor. It will allow you to make a wide variety of adjustments without a box full of parts.  21: A set of Hooker 2-into-2...  21: A set of Hooker 2-into-2 Exhaust pipes was chosen to finish up our hop-up. In addition to being a great-looking pipe that allows us to retain our 2-into-2 styling, they come with an adjustable ring at the outlet of each pipe that will allow small adjustments to affect the characteristics of the motor. These adjustments also affect the sound emanating from the pipes.  22: Doc readies the Hooker...  22: Doc readies the Hooker pipe to be installed on the primary side of the bike. The pipes come complete with necessary mounting hardware and full-length heat shields. Once the pipes are installed, it is important to clean them thoroughly. If this is not done, the oil from your hands will have a tendency to burn down into the chrome, making your brand-new exhaust system look not so brand new.  23: Once the bike is back...  23: Once the bike is back together, Nigel hooks up his laptop and loads a map into the Power Commander II. The Power Commander II comes loaded with a default map, but to get the most out of the horsepower potential of our new motor, Nigel loads a map that he knows will take full advantage of everything the motor has to offer. If you purchase a kit from Nigel, he will download the proper program on a disc for you to install into your Power Commander.  24: Once the bike had some...  24: Once the bike had some break-in miles logged on it we took it, back to Patrick Racing and put it on their dyno. After a few runs and a little tweaking, the motor put out 83 horsepower and 86.7 lb-ft of torque. Our not-quite-stock Evo registered 56 horsepower and 62 lb-ft of torque. This modification also works great on a Twin Cam motor, while yielding even more horsepower than it did in the case of our Evo. All this and we still have the stock air cleaner in place. If we changed that as well as a 2-into-1 pipe...well, that's another story.
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