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"K13S/R" Technical Q&A K1200S/R Technical Questions/Answers

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Old 01-08-2018, 03:20 PM
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PCFC - Duty Cycle & Pulse Width?

Could someone help me understand why Dynojet has 'Duty Cycle' and 'Pulse Width' on the main computer screen? How are these helpful in understanding what's going on? I have the most rudimentary grasp of the three areas involved with the injectors, duty cycle, frequency and pulse width. I don't think Dynojet would use window dressing. Although, once again I'm having difficulty finding anything on their web site. I have noticed the numbers drop as the engine warms up. They also seem to become more similar. Thanks for any help.
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Old 01-08-2018, 04:44 PM
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Re: PCFC - Duty Cycle & Pulse Width?

Duty cycle is what percentage of time the circuit is turned on.
Pulse width is how long the circuit is on per cycle.

50% duty cycle means circuit is on 50% of the time of each cycle. Whereas pulse width is an actual number in milliseconds.

So it's important to know how long the injector is on to determine how much fuel is being injected into the engine per cycle. However, it is also important to know if the injector maxes out or drops too low so that fueling becomes erratic.

What does this mean? Well, the faster the rpms, the shorter the time available to inject fuel. If at some point, the fuel needed by the engine exceeds the time available, you know you need to upsize the injectors.

None of this really is important on a stock or mildly modified engine as you would think that the factory did its homework and sized the injectors correctly.
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Old 01-08-2018, 05:15 PM
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Re: PCFC - Duty Cycle & Pulse Width?

Ah, so size does matter! Didn't think I would hear that on a motorcycle forum. So it is a bit of window dressing. There is no real practical use at this level but offers some insight to the dynamics taking place. The ability to manage the number of variables is the evolution of sophisticated engineering. For me, a small insight can bring marvel at what is before me. Thanks for the response.
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