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Steve, Motorcycle Mechanic
Category: Motorcycle
Satisfied Customers: 6813
Experience:  30+ yrs. experience, MMI, HD technician, HD early, engine rebuild/performance, bike builder, kit bike program manager, CCI 2001-2004
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98 iron horse, stopped running on me, have replaced battery

Customer Question

98 iron horse, stopped running on me, have replaced battery twice in a year, and now with a new battery it will turn over but not fire. Getting gas to carburetor. Sure it is an electrical problem. If the voltage regulator is bad would that be enough to not have enough spark at the plugs and to drain the battery
JA: Did you test the battery with a voltmeter? And have you ever changed one before?
Customer: Yes, brand new battery
JA: What is the model/year of your motorcycle?
Customer: 98 American ironhorse
JA: What year is your motorcycle?
Customer: Sorry meant 2005
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: Thought is was the coil checked for continuity, not sure what the actual specs should be, but it I think they were within reason
JA: Anything else you think the mechanic should know?
Customer: The person that owned it before me had hooked up led lights that have never worked , I pulled all of them off
Submitted: 3 months ago.
Category: Motorcycle
Expert:  Steve replied 3 months ago.

we should just start at the beginning.

measure the battery voltage under the following conditions:

- ignition OFF.

- ignition ON.

- with the start button depressed.

let me know what you find.

we can continue then.


Customer: replied 3 months ago.
Off was 12.93
On was 10.55
Expert:  Steve replied 3 months ago.

and with the start button depressed and the starter turning the engine?


Customer: replied 3 months ago.
Customer: replied 3 months ago.
On both
Expert:  Steve replied 2 months ago.


- turn the ignition off and measure the battery voltage.


-turn the ignition ON and measure the battery voltage.


- with the ignition ON and kill switch to run, press the start button and measure the battery voltage.

please provide all 3 voltage readings.


Customer: replied 2 months ago.
12.77 key off
12.73 key on
10.36 turning over
Expert:  Steve replied 2 months ago.

your battery seems fully charged, but the voltage during starter operation is too low to allow the ignition to make spark.

- this usually means the battery is old and worn out, or a cheap Chinese battery. but it can also mean there is a problem with the battery cables. they may be loose or there could corrosion build up where the terminals are crimped on the cables.

see what you can find.


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