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Steve
Steve, Motorcycle Mechanic
Category: Motorcycle
Satisfied Customers: 6908
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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90 flhtc. after riding 40 to 50 mins, the voltage will start

Customer Question

90 flhtc. after riding 40 to 50 mins, the voltage will start to climb the regulator will catch and drop back to 13.4. This will happen 5 to 5 times and then peg the gauge at 16 amps. After several test on stater and voltage regulator I finally decided to change regulator resulted in no change, after more tests, I decided to screw it replaced stator and voltage regulator as a brand new pair. No change. Forgot to mention, replaced battery with brand new Harley battery. Took digital tester on ride confirmed gauge is accurate. My last attempt was to run a separate ground wire from base of regulator to negative post on battery to eliminate all of my grounds. No help. The problems has been accuring at shorter intervals. Can shut bike off and restart with no change unless bike is completly cold. Even replaced main circuit breaker. Continuity test of battery cables. HELP!
Submitted: 1 year ago.
Category: Motorcycle
Expert:  Steve replied 1 year ago.

the dash gauge is a VOLTMETER, not an ammeter.

it reads in volts dc.

the only thing that can cause the gauge to read high volts is a bad regulator.

you may have bought a bad regulator.

again.....the only thing that can cause voltage to read high, is a bad voltage regulator.

let me know if you need ore help.

Steve

Customer: replied 1 year ago.
I've borrowed known good regulators with no change. I'm on my 4th regulator. This is the answer i always get. Not regulator.
Customer: replied 1 year ago.
All tested good even the original . And yet the problem still exists. I apologize. I said amps and meant volts.
Expert:  Steve replied 1 year ago.

your power train is rubber isolated from the frame.

your bike has 2 battery cables and a power train to frame ground strap.

- a cable connects the POS battery terminal to the starter.

- a cable connects the NEG battery terminal to a starter mounting bolt.

- a ground strap connects the frame to the inner primary, underneath the transmission.

ensure all cables are in good condition with a clean and tight connection at both ends.

I have seen this problem before. I had the same problem with my 1992 FLHTC.

the first time it was the ground strap ot connected to the inner primary.

the second time it was a bad brand new regulator.

Steve

Customer: replied 1 year ago.
Thank you. I've tried all that. Replaced and tested cables. Cleaned cables, jumped cables, jumped grounds. Getting tired of buying new regulators. Could it be something in wiring
Expert:  Steve replied 1 year ago.

the battery provides the power to run the bike.

the regulator keeps the battery charged.

the battery is the surge suppressor for the system.

your bike will not operate without a battery connected.

- the only other thing I can think of is if you are losing the battery connection.

- the battery pos terminal is connected to the starter. on that terminal of the starter is also a wire which connects to the main circuit breaker.

if this wire is not making a good connection between the pos battery cable and the main circuit breaker, you might be seeing a surge caused by loss of the battery.

Steve

Customer: replied 1 year ago.
I have no problem with paying just please continue to give it thought. I'm lost. Bike runs fine. Please reread original message.
Expert:  Steve replied 1 year ago.

reply to my last post.

Steve

Customer: replied 1 year ago.
Cleaned both ends of battery cables. Cleaned starter connection. Removed and replaced circut breaker. Really appreciate you taking time but this is why I'm so frustrated. I keep hearing what I've already done.
Expert:  Steve replied 1 year ago.

to this point, you have YET to address the issue in my LAST POST.

please read it carefully.

please ensure this is not your issue..

Steve

Customer: replied 1 year ago.
Checking it today. I will let you know results.
Expert:  Steve replied 1 year ago.

let me know if you need more help.

Steve

Customer: replied 1 year ago.
I do. Good connection. Cleaned both wire and post. No corrosion. Still stumped.
Customer: replied 1 year ago.
Just want to remind you that length of time is very important. It takes 40 mins or so before it starts happening. And then it bops around before it pegs out. Went to Sturgis last year, first noticed it on ride home. The time before it starts has progressively gotten shorter
Customer: replied 1 year ago.
I have the faring, seat and tank off now. going through it a wire at a time. Problem is I probably won't know exactly what the problem is. I would and do appreciate all your insight as I am completely stumped.
Expert:  Steve replied 1 year ago.

it seems I won't be able to help you.

best of luck.

Steve