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ignition trouble maybe??

O

ORTIGO

Member
curious if anyone would know what makes a bike only fire when I let go of the start button? It flat out wont fire until I let go. 89 sportster 883
 
When I try to start the bike it doesnt matter how long I turn it over. It only fires up and runs when I let go. Sorry to mislead I havnt actually pulled the plugs while trying to start. I will if you think I need to.
 
I am working without a schematic so I am only guessing. Since your bike is a 1990, was it a points ignition system or were they solid state by then? If it is a points system, it is very possible your ignition system uses a ballast resistor on the primary side of the coil. If it does, in most cases the ballast is by-passed during cranking in order to hop up the secondary output of the coil. Sounds like that may be the case here. If the circuit that bypasses the ballast was failing, you would have exactly what your experiencing.

Could tell you a lot more if I had a schematic.
 
What Hoop is referring to is a holdover from the old 6V/12V days (anybody remember that). Originally old Ignition systems were designed for 6V operation, 12V was a cost reduction, simplification of the starting system to have more power available and less massive components using less current with less loss (Ohms law...more voltage, less current and resistance losses for given power, with the wiring no longer the diameter of you thumb, more like your little finger).

Of course the problem was, once running, that efficient 12V makes more voltage available for starting mode, but too much in running mode, being hard on points life with ignition system portion of the design still geared for 6V operation continuous running. The ballast resistor would be switched in once the starter had spun engine to life with ignition extra hot, but then put into "Run mode" with ballast resistor in..to save those points from arcing and burning.:D
 
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NewHD,,, Stop Stop your giving away my age. I bet I can go out to the garage and find a ballast resistor and a set of points out of something I drove 30 years ago. The days when "points, plugs & condenser" was a tune up! :p
 
Hoople said:
NewHD,,, Stop Stop your giving away my age. I bet I can go out to the garage and find a ballast resistor and a set of points out of something I drove 30 years ago. The days when "points, plugs & condenser" was a tune up! :p
Click to expand...

lol I remember the tail end of those days, Thanks for the comments guys.
 
Yeah I too remember ballast resistors if you owned a Chrysler you had a spare in the glove box, most ignition systems today have a resistor wired in the ignition wire
 
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