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Need to by pass ballast resistor Magna 5.0 OHM coils using Dynatec electronic ignition. Magna notes and 4into1 possible point of failure, blew my fuse

Bhitt_us

Bhitt_us

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CB750 1971 problems blow fuse on startup. Suggestion to disable or by pass Need to by pass or disable ballast resistor with these coils Magna 5.0 OHM coils using Dynatec electronic ignition. Older Magna notes not online anymore and 4into1 indicates possible point of failure, blew my fuse several times in a row
 
5 ohm coils are the same rating as the stock coils. I've been running Dyna ignition for thirty years without issue combined with either 3 ohm or 5 ohm coils. I would start looking at connections making sure everything is clean, tight, and properly insulated (no shorts). Where are you using a ballast resistor? I've never used one.
 
i understand a ballast resistor is to restrict current to the starter motor so that the ignition gets its full working power, it does on cars anyway
 
kirky said:
i understand a ballast resistor is to restrict current to the starter motor so that the ignition gets its full working power, it does on cars anyway
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Yes, but I have yet to see one on a SOHC/4 unless someone felt compelled to ad one...

The ballast resistor is used on older automobiles to restrict current to the points to keep from burning up the points so quickly when running. In start mode the ballast is bypassed to push full current to the points for easier starts. I am not aware of any ballast resistor used on the SOHC/4's, since when properly tuned the bikes start easily and aren't pushing enough current to the points to be worried about them burning out. Stock points last quite a long while on the SOHC/4's.
 
Using the right coil for the ignition used eliminates any need for a ballast resistor. Do you have "high performance" coils installed? Using a low ohm coil would be the only reason to use a ballast resistor on that bike with a stock ignition. An ignition without points generally uses 3 ohm coils.
 
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