FREE PERFORMANCE SEMINAR

Are you getting the most horsepower from your motorcycle while keeping it reliable and dependable?  Let’s start with the basics…think of your engine as an air pump – you need to get as much air threw the engine as possible.

AIR FILTER – The air filter is the first place to start.  K & N air filters flow the best…not stock paper filters or foam filters with oil in them.  Also, the diameter and thickness of the filter is very important for flow. Thin and small diameter filters choke the engine off. Some may look trick, but that is it. Zipper filters with large diameter and taper shape toward ventury work the best. You will gain approximately two horse power with just this filter design. Air pulled into a tapered hole increases velocity. The straighter the shot to the carb or throttle body, the better your results. When choosing an air filter, the backing plate is also important when buying a hi-flow kit. You want a velocity stack design in the backing plate. This helps air velocity going into the carb. When changing to a good hi-flow air filter system the stock carb or fuel injection will require more fuel in the idle circuit and off idle throttle positions. On carb models, this is done with the fuel screw and a larger pilot jet. On fuel injection models, some type of fuel management is needed. This is attached to the ECM (electronic control module) to richen the mixture.  We recommend the Dynojet Power Commander, which is far superior to anything else on the market. The PC allows us to change air and fuel mixtures, throttle position, timing and accelerator pump features as many times as needed. Custom maps can be made for each cylinder; also the Rev Limiter can also be changed.  The PC can be moved from bike to bike, as long as it is compatible with the fuel injection type, i.e. Delfi, Magneti Murelli, and decel pop (FLH model pipes can be removed). We also use the Thunder Max EFI control module which uses both O2 sensors and adjusts itself to the targeted air fuel mixture in the chosen map for your modification. We also recommend this system tp replace the Harley-Davidson Race Tuner, Thunder Max also has teal time data and air fuel ratio graph and can clear engine codes, all on your laptop. Other less expensive systems are used as Vance & Hines power pact, etc. But these are only adjustable enough for minor modifications such as air filter and exhaust. In some cases with unknown engine modifications, air filter and pipes, a custom map may be necessary. This can only be done with a dyno/gas analyzer and proper program with an Eddy current brake and should be performed by a registered Power Commander Tune Center. The Power Commander is easily removed before going to the dealership if there is a warranty issue. All Harley-Davidson’s are lean from the factory due to emissions laws. Therefore, there is a great need for more fuel when making these modifications. Fuel injection (Delphi) is very efficient for hop ups and can exceed horsepower and torque over a carb model. It is more tunable throughout the throttle positions and can keep a consistent air fuel mixture, not to say they start easier and compensate for altitude and air temperature.

EXHAUST- Choose your exhaust system with your future hop-up in mind.   Two into one exhaust systems are the most efficient for scavenging the exhaust gases and pulling fresh air fuel mixture into the combustion chamber, which is also affected by cam overlap from aggressive cams and makes these types of pipes a must. If you can’t live with the look or sound of two into one pipe, there are some tuned one into one pipes with taper reversion characteristics or cross covers built into these pipes.  These work well and still have the traditional sound. Drag pipes are great for top end performance on drag bikes that are tuned to run on top end.  But for normal street use, low end and mid range tuning is more important. Drag pipes hinder performance and rob your horsepower. FLH cross over style pipes are the worst exhaust on the market. True duals with a good slip-on are the way to go if you want to keep the traditional look. But once again two into one pipes are superior even on baggers and weigh less.

DISPLACEMENT – Changes are easily accomplished on twin cam motors by simply boring the cylinders out for large displacement pistons.  There is plenty of sleeve thickness on a TC cylinder to achieve 95 cu. in. from 88 cu. in., 103 cu. in. from 96 cu. in. without changing the stroke. There is no need for new cylinders, although larger displacement engines can also be built from TC engines and EVO engines by total engine tear down and splitting engine cases and installing flywheels with longer stroke and machining case to except larger displacement cylinders. Stroke changes and larger cylinders effect the life and dependability of the engine and the motorcycle, with more wear on the cylinder and rod and more maintenance on the motorcycle from vibration and its drive train component from more horsepower and torque. The new 96 cu. in. engine can easily be changed to 110 cu. in. also with pistons and cylinder boring.

DECK HEIGHT – Setting piston deck height is very important for good combustion efficiency.  As the piston approaches TDC (top dead center), the air/fuel mixture residing in the squish area is squeezed toward the ignition source.  This promotes turbulence and a faster, more complete burn.  Another benefit of high turbulence is to reduce high-octane requirement and help prevent detonation.  This is an engine building step that is often left out and is not a part of Screaming Eagle kits from the factory. See above diagram.

 

Detonation – Normal combustion is not a violent explosion.  Instead it is a process where the air/fuel mixture burns in a smooth, steady motion with the flame front expanding from the spark plug until the entire mixture is burned.  If unburned air/fuel mixture is excessively elevated in pressure or temperature, it will explode in several spots without waiting for the flame front to ignite it.  This results in a violent collision of flame fronts after the spark plug has fired.  In this situation, the pressure rise is quick and violent and can result in engine damage.  The noise resulting from detonation is caused by the collision of multiple flame fronts in the combustion chamber and is frequently inaudible because it can be drowned out by exhaust sounds.

Pre-ignition – Pre-ignition is frequently confused with detonation.  Where detonation occurs after ignition of the intake charge, pre-ignition ignites the charge before the spark plug firing.  Pre-ignition is caused by a hot spot, which results from a red glowing body in the combustion chamber.  Pre-ignition will always occur before ignition takes place, while detonation always occurs after ignition starts.  Pre-ignition can lead to detonation, but detonation will not lead to pre-ignition.  Pre-ignition is caused by hot spots and destroys an engine by heat.  On the other hand, detonation is caused by high pressures, low fuel octane or air/fuel separation and destroys an engine by mechanical shock.

CAMSHAFTS – Since the camshaft defines the engines power curve and personality, camshaft selection is both a science and an art. There is no one clear answer for the correct camshaft as there is more than one opinion and a huge selection of cams on the market. Track side or Dyno testing is the only sure way to know how a cam is performing with a particular engine combination.  Knowledgeable engine builders rely on experience and follow proven guidelines when selecting a cam.  The cam combination we use works well low end and mid range, and most important, at highway cruising speeds (2800-3200 RPMs) when you need the power most.  Most people do not ride wide open all the time. There is a lot of math available on camshafts. Engine specs are required when selecting a cam. Long duration cams with valve overlap work well at higher RPMs and in the higher power band. Less overlap creates more torque throughout the RPM range. Higher lift allows more fuel air mixture for larger displacement motors and ported heads. There is always more engine noise with cam changes. Higher compression pistons are needed to retain cranking pressure with camshafts that have a lot of valve overlap. Compression created horsepower but with today’s gas pump, high compression pistons cause excess heat and pinging. Engines with 9:5 compressions are more rider friendly.

Removing the stock chain drive on twin cam models and replacing with gear drives is highly recommended for three reasons – more positive cam timing, less drag on motor, and more dependability.  They are stronger and have less wearable parts.  Stock cam chain shoes wear out fast.  Full synthetic oil substantially cuts down on cam shoe wear. Excessive wear is found at 12,000 miles and up; with good maintenance the oil filter should be cut apart and inspected for cam shoe pieces and metal. We try to catch this problem before engine damage results.

Engine, lifter block and rocker box clearance should be checked and machined as needed with all larger cams.  We also install heavier roller bearings in the case and cam support plate when installing larger cams.  Stock bearings can not handle the load, just as lifter rollers need to be stronger with the increase of valve spring rate and cam lift.  Synthetic oil really helps reduce friction.  Stiffer valve springs are a must to get the valve closed, especially at higher RPMs.  Also piston to valve clearance must be checked and a minimum of .030-.040 clearance is required when rotating the motor.

LIFTERS – Lifters are important when installing a cam shaft.  A solid lifter provides the most positive valve opening, but with cylinder expansion. This causes more valve lash and these lifters are very noisy.  Hydraulic lifters take up this valve lash which is caused by heat expansion, thus keeping the engine quieter. However, these can collapse at high RPMs causing the valves not to open completely or worse over pumping causing a valve to hit the piston.  We like the Jim’s Hydro solid lifter.  Not only are they beefier than stock lifters, but you get the best of both worlds with the lifter turning to a solid at high RPMs and a hydraulic at low RPMs.  This keeps the motor quiet.  They also have a built in anti-pump up device to prevent valve float at high RPMs.  Stock lifters on EVO engines should always be changed

as they tend to go out at about 10K-20K miles.  Twin cam lifters are a better design and tend to last longer.

VALVE TRAIN – Valve train must be light and durable enough to accurately transmit the cam lobe motion to the valves.  Light weight, adjustable push rods are used. Roller rocker arms are used for more rigidity and less friction at higher RPMs. For normal street use and everyday wear, we find that stock rocker arms work best.  Synthetic oil reduces the friction substantially.  On some cams, clearance on rocker boxes must be checked and adjusted as necessary when different rocker arm ratios are used.

HEAD WORK – Head work is very important to get the maximum horsepower from your hop-up.  We feel and it is a fact that stock heads that are ported with larger valves and have reshaped ports flow more than Screaming Eagle heads and most after market heads.  In most cases they are also less expensive and don’t need a special piston design to match the heads.  This makes piston selection easier and less expensive while maintaining the stock look.  Opening up and shaping the port increases air velocity and fuel atomization.  This needs to be done on a flow bench by an experienced master.  We send all of our heads out and offer an exchange to reduce turn over time.  Also, premium valve guides, springs, and valves are used in these heads so they are pretty much ready to bolt on.  We also do 3-angle valve jobs in house on normal head work.  Polishing is an extra charge and is a fine edge for performance as polishing helps keep carbon from building up and also retains heat in the combustion chamber and exhaust port.  This helps with burn rate and greater gas expansion; and higher export velocity.

CARBUREATION – Carburetor changes are very important with hop up.  The stock carb is too restrictive and not adjustable enough for engine modification.  The stock carb is restricted by the throttle shaft and butterfly, plus the slide.  The Mikuni smooth bore carb has no restriction and has a more efficient venture design and a larger diameter venture.  Therefore, there is quicker throttle response and enough flow for ported heads.  We feel this is the most superior carb on the market.  Although S & S makes a great carb, they still have older technology and work well on shovels and iron head sportys. We take early EFI systems and M & M and convert to carb. This males the bike run and perform better.

IGNITION CHANGES - There is really no horsepower gain from ignition changes, except for being able to change rev limiter.  This allows the use of horsepower that the cam can deliver at higher RPMs.  Most cams keep making horsepower to 6200.  Stock rev limiters are set between 5400 and 5800 RPMs. Horsepower gain can be made by fine tuning advance curves - the rate of advance, and the total advance.  This helps prevent detonation and reduces engine temperature.  Single fire ignition is important for proper ignition timing.  All new H-D’s come stock with single fire for 99-UP.  There are ignition packages available for Evo’s.  Dual plugging is also an option.  The advantage to this is more efficient combustion burning so that the lower octane fuels that we buy today have less chance of detonating.  Running colder heat range on spark plugs will also keep engine temps down. This is commonly needed with high compressions pistons.

OIL COOLERS – Good oil coolers are a must with any air-cooled engine, especially stock or high performance engines. By good oil cooler, we mean radiator style and black - chrome doesn’t dissipate heat.  There are a lot of oil coolers out there, but with temperature readings taken on engines, this type is the only one that works.  Synthetic oil also contributes to cooler running temperatures.  Oil pump change can also help more flow and return.  We use a Zipper shim in the pressure relief valve to create more pressure. On balance engines to much oil pressure can result in damage to balance chain shoes which have hydraulic tensioners.

EASIER MOTOR TURNOVER – Getting motor to turn over easier, especially large displacement motors of 100-124 cu. in. can be accomplished by installing compression releases.  Easier ways are gear reductions on starter pinion drive and clutch hub, and up dating to a 300 plus cranking Drag Specialties amp battery. We try to keep cranking pressure around 145-160 PSI. This makes for an easy starting engine.

CLUTCH UPDATES – We have not had many clutch problems, as stock clutches seem to hold up well (depending on riding style).  Heavier clutch springs are recommended, but will also make your clutch lever harder to pull.  There are easy pull kits available to solve this problem.  Bikers with higher mileage, a high performance clutch plate kit would be advised.

GEAR CHANGES – Gear changes on front drive pulleys, especially on FLH models and when pulling trailers, make a big difference in engine performance.  It is not as necessary on lighter bikes unless you want to come out of the hole quicker or pull wheelies easier.  There are motor sprocket changes available that do basically the same thing.  A 6-speed tranny conversion is the ultimate way to use the horsepower and torque available. Most six speeds have a lower first gear and will lower your RPMs at highway speeds.

BREAK –IN PERIOD – The break-in period is crucial.  Very easy the first 100 miles and try to cool down often.  Petroleum based oil should be used for the first 500 miles so rings can seat.  We then recommend changing to 20W60 synthetic oil and change oil every 2500-3500 miles.  Redline 20W60 synthetic oil quiets the engine and provides better protection on hot days.

We at Sangers Cycles, Inc. take great pride in our workmanship and our customer service.  We strive to give the customer the most accurate and honest information available to us.  If you have any questions or comments, please feel free to contact us.

Thank you!!                      Kevin & Kay Sanger and crew.

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