Vacuum line/timing

Information and questions on GL1200 Goldwings (1984-1987)
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Location: Madisonville, LA
Motorcycle: 1984 Goldwing Bobber

Vacuum line/timing

Post by Outbound86 »

Question, --- a vacuum line from the #4 carb goes to a black box which I believe is the timing control. I have also read that the gear selector has some control over the engine timing in each gear. What is the plus or minus of leaving the vacuum line off the black box? Do I get the same full ignition advance in 4th and 5th as I get in the first three gears? I'm looking for a little more engine timing but need to know if the electronics are offsetting any changes that I make. Thanks

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Re: Vacuum line/timing

Post by virgilmobile »

The module is the heart of the ignition system.The vacuum line does advance the timing depending on rpm and gear selection..As I recall,the timing is preset and when 4th or 5th gear are selected,the vacuum change (rpm change) moves the timing further.
Specifically the timing changes start at 15-1700 rpm and max out at 28-3200 rpm.This is from the vacuum on that line starting at 1.4" of vacuum and maxing at 3" of vacuum.
There is no vacuum at a idle.

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