1) What instrumentation, if any, is attached to the bike? For example, is the exhaust analyzed chemically to determine air/fuel ratio? Is the fuel flow measured? Is something else measured?
You only need two inputs. A tach signal for rpm and either 1) a tube inserted into the exhaust pipe, or 2) wide-band O2 sensors screwed into bungs in the head pipes.
2) What changes are made to the bike and what is adjusted during/between dyno runs to accomplish the "dyno tune"?
The only way to tune is to have a means to make changes to the fueling. I will do this assuming there is a Power Commander fuel controller on the bike, since this method is the most common over all brands of motorcycle and the most involved.
You warm up the bike and re-set the throttle points/tps for zero throttle and 100% throttle.
You will tune the front cylinder 1st.
You run the bike at idle and set the desired air-to fuel ratio at the rpm range where the bike will normally idle.
You put the bike in 4th or 5th gear and do a dyno pull at 2% throttle position and save it. The dyno will show a graph through the rpms from the lowest to the highest it revs at that position.
The dyno software will show an air-fuel graph at the bottom like this (The dashed line across the graph can be set to the desired ratio by the operator):
The Power Commander software has a fuel table like this:
Now... the operator will adjust the cells at each rpm, over several sampled pulls at 2% throttle position, until the air-fuel line is flat across at the target line. Then he will move on to the next higher throttle position (5%) and do it again... until he has done all the way up to 100% throttle.
Then, the operator will switch to the fuel table for the rear cylinder and move the O2 sensor to the rear head pipe and start over... tuning the rear cylinder at each throttle position through the entire rpm range.
There is also a table for ignition timing, but that's another topic...
3) Wouldn't the changes made to one brand of bike likely be different than the changes made to another brand? For example, if you were dyno tuning a Valkyrie, you would need to know how to adjust and synchronize the six carbs. If you were dyno tuning my 2006 HD softail you would need to know how to manipulate the fuel injection (probably by the addition of an aftermarket fuel controller). If you were dyno tuning a vic, you would have to deal with a different fuel controller and the O2 sensors.
The proper air-to-fuel ratio is the same for all 4 stroke internal combustion engines. If tuning a carbureted bike you would have to disassemble the carbs and change jets, adjust needle heights, and set the pilot screws to achieve the proper fueling. On a fuel injected bike you do this electronically thru the fuel controller. With a Power Commander, the stock O2 sensors will be deleted (they are not used, since the tune will be open-loop).
4) Do dyno tuning experts know all/most of these various tuning methods or do they specialize in one brand?
Either you know how to tune or you don't. Whether it's a single cylinder dirt bike or a 6 cylinder Honda, the process follows the same principals. You make the air-fuel ratio correct. Whatever it takes to achieve that.
The dyno is just a measuring tool that allows you repeatable measurements... like a yardstick... it doesn't do any tuning.
2006 Victory Kingpin
Lloydz 116" Stroker/Big Bore, .495 Cams, Torque Tubes Airbox,
RPW Thor Pipe, Lloydz ECU Flash, PC-III, PTS (-2), Rivera
Primo Clutch Spring, 31 Tooth Pulley w/Buell Belt.