Tuning 9/1/2006
“Hi Mack, I brought my ride in for a tune up.”
To a lot of people they perceive this to mean, ‘change the oil, check it out and declare it safe’. Webster defines tuning as, ‘to put in first class working order’.
To tune a musical instrument you must first know what key the instrument is to perform. The key to tuning a machine is knowing how its operator intends to use it and enhance the machines components to better perform these tasks.
A service is how the machine is maintained in its intended duties, as well as, making wear created deficiency adjustments.
There are six most common requests I hear as a tuner. Number one is for the machine to have more sound. This is usually accomplished by an exhaust change, either by a muffler swap or entire exhaust system change for a specific tuning enhancement.
The second is a carburetor and air cleaner upgrade to move more air through the engine for better throttle responses just off idle. Should the machine be injected, the air cleaner change would be accompanied with a stage one down load chip, digital fuel optimizer or a power commander to electronically rejet.
The third most common request is for more pulling power for cruising and touring. This upgrade allows the rider to make better foot pounds of torque so a constant speed can be maintained with less throttle.
The fourth most common tuning request is more horsepower. This is quicker RPM to reach maximum torque. This is for the people who like traffic light to traffic light runs.
The fifth most common request is suspension tuning which can help the ride ability for the comfort of the rider. Spring rate changes, spring tension changes, shock changes and fluid changes will help to stiffen or soften suspension, as well as, raise or lower ground clearance.
Traction tuning, the sixth most common request, is also tricky. You have many things to consider, such as; engine power, drive line strength, tire height, tire width and tire compound. Sprint compounds are soft compounds with good cohesion for either aggressive cornering or rocket starts, but are low mileage short life tires. Now days, Avon and Metzler are the leaders in the world on cutting edge tread design, as well as, new H rated compounds (H being highway rated for long life). They have found ways to lay the cords in the carcass of the tire to transfer load from sidewall to the foot print on tread area for sure footed grip. The new rubber additives, which have chemically created stronger rubber that grips well, but resists premature wear, is now 21st century technology. These coupled with digital created tread patterns promise some really interesting riding with even greater possibilities. Traction is also related to air pressure. Higher pressures tend to run cooler and last longer. Low pressures will give you a soft ride as well as hook up and will also launch well, but will be short lived regardless of the compound. Low air pressure will also cause cornering problems such s wobble, squirm and low speed wiggles.
Tuning a machine for a specific purpose, rather that purpose is touring, around town, road course or drag strip; all components must complement one another while key components related to the largest goal are to strengthen the unit.
Now that the project is completed make sure you keep it on a regular service schedule to protect your investment and riding pleasure.
A good example of tuning is Danny Arnold from St Louis, MO. The Twin Cam Dresser Danny rides in the street dresser class is machined, built and tuned by him. This is a good example of precise tuning as any racer will be quick to tell you the proof is in the details. So, I can assure you, as a tuner myself and working with a 33 year old machine, the smallest details is where power is found.
Good Riding and God Bless!
Steve Caldwell - steve@precisionvtwins.com
877.429.0399