I have similiar problem on 05. Just didn't remember it till I saw your post. If I activate signal early in traffic, by the time I get to corner it is off and I have to hit it again. Blinks like 5 - 6 times. Hopefully someone has info. I thought maybe it was adjustable somewhere on the bike.
I also claim the right to be wrong however, I found out on my 1500 and now the 1800 that if if push the signal button firmly, left or right, a couple or more times, the signal stays on until the angle sensor turns them off. I know there is no valid explanation for why it works this way but, it works for me. I can sit at a stop light forever or indicate a turn while riding without the turn signals turning off until after the turn. All I can say is try it, nothing lost.
Here's what the Owner's Manual says (2005, page 33): The turn signal switch is used to signal a turn. To operate, move the switch all the way to the left or right and release it. The appropriate turn signal lights will start blinking. The lights will automatically stop when you complete the turn. (You can manually cancel the lights by pushing the switch in.)
To signal a lane change, move the switch all the way to the left or right and release it. The turn signal lights will automatically stop in 7 seconds or after riding 110 yards (120 m).
In town it doesn't stay on long enough. On the highway it stays on too long. You just have to live with it. Just get used to hitting it two or three times in town and manually cancelling it on the highway. That's the way most of us do it.
Rich - If your signals truly cancel after 3 or 4 flashes, you have a defective cancel unit and need to get it replaced under warranty. The minimum you should get is 11 flash cycles.
The cancel time changes based on your speed. Also, if the wheels are not moving, the unit will not self cancel (like sitting at a stop light). It does not use the bank angle sensor, but instead uses a small angle sensor on the bottom of the steering head that senses handlebar movement (not lean angle). This sensor is essentially a rheostat (variable resistor) that feeds a sensing circuit. It can tell when you move the handlebars off center, and then back again. When this happens it self cancels. If no handlebar movement is sensed, it then cancels when it reaches the time out period.
All speeds above 35mph it canceled at 12 flashes at 7.4 seconds.
Sometimes the number of flashes would vary by one flash depending on where the last flash fell in the time window. For example, at 35mph sometimes I would only get 11 flashes, and sometimes I would get 12, and once I got 11 1/2 flashes when the time window cut off in the middle of a flash cycle. This tells me that the circuit is not counting flash pulses, but is either measuring time from a clock circuit or is counting pulses from the speedometer.
I suspect the circuit is not only looking at the number of pulses coming from the speedo, but is also looking at their frequency to determine speed, and has different cancel counts for different frequencies.
Further calculation from the above times shows the following:
speed (MPH)-----speed (ft/sec)----- Distance traveled until cancel
Here is the cancel unit removed from the bike. It is inside the steering head.
Here is the bottom of the cancel unit, look up under the forks. The rheostat is in the center of the unit and connected to the wiper arm which is fixed to the bike. This causes the rheostat to turn when you move the bars. Many times, this wiper arm will come off the tab on the rheostat, resulting in signals not properly canceling after completing a turn.