Ok on a little vacation to the Tail of the Dragon. Pulled off at a little rest area in Cherokee and the bike quit. Hooked the little bump box up and it started, but when I unhook the jump box the bike dies. Had to get a tow over the mountain to our hotel.

Now for the question. Should the bike run on just the stator? Or would it die? I keep a close eye on the volt meter and it never went down to 14 volts. It stayed were it always does. Just kinda wondering.

 

Last month a friend of mine's Street Glide had the same issue. We jump started his bike and he rode it 150 miles until we could buy a new battery. I have heard Harleys won't run on just the alternator like a car will. He kept going but, perhaps his battery had just enough left. His charge indicator showed a bit over 14 volts.

 

Newer bikes and cars need the circuit completed. If your battery is just dead it will run, once you boost it. If it has an internal short, or break it will not complete the circuit and stay running. The jump box was doing that for you until it was diconnected.

 

SJ is correct. If wired correctly, it could since one side of the alternator is permanent magnets but it is not wired that way with relays and such.. Unlike a car, it truly does not need an exciter (battery voltage going thru one side of the alternator since that is the permanent magnets in a Harley). Car alternator has just wire on both sides of the alternator and therefore needs needs a battery to even function. They have one carbon brush that probably would not work all that well inside Harley's oil slung primary.
The alternator on a Harley is truly a Magneto AC alternator.

 

No, it requires a good battery to stay running.

Even a modern car will not run on just the alternator.

Anything with fuel injection and computers requires a good battery.

 

http://www.hdopenroad.com/open-road/...rging-systems/

 

Thanks for the replys. I'm hoping it the battery. I will charge it and have it tested, and go from there.

 

Rev. 08-08-16
Some electrical 101 and a little more..

Remember, the best made brand new battery that has been on a maintenance charger for 3 days that has a loose or bad connection is no better then a boat anchor with a loose rope. The connection can get loose after one ride if the battery is not anchored and the wires are short and get tugged in a direction that can unscrew the bolts.

After a good 24+ hour maintenance low amperage charge, with the charge light in the solid green and the battery has set about 24 hours off charge, voltage should be about 12.8 volts.
12.8 = full charged
12.6 = 75% charged
12.3 = 50% charged (Lot of new modern cars with system protection will not even click at this point but will have good headlight beams showing)
12.0 =25% charged

Always check both the terminals at the battery lead and also at the terminal on the wire. That helps to verify connection. With a DC volt meter (one that has a feature to lock high and low reading is best) hooked across the battery terminals and reading 12.8 or so, crank motor and while its cranking it should not drop below about 9.6 volts and as soon as it starts and throttled up to 2000 rpm, voltage should read around 14.8 volts. The 2000 rpm is the bench mark standard. Ignore idle output. Ignore output above 2000rpm unless it exceeds 14.9 volts. That is a sure indication that regulator is bad.

The crank check shows a rough check of the reserve amperage capacity of the battery while cranking with a 150-200 amp load on it. The 14.8 shows a good alternator and if you leave it on a while as the regulatory will drop the voltage a little showing itself working. However, with the lights and stuff always on, it will never drop back much. If you have a lot of options, most modern bikes will not show 14.8 charging volts at idle but stock newer bikes will be close. Older bikes with lower amperage output not so much. However, 2000 rpm is the bench mark for the standard 14.8 volts.

If you think battery is good and something is draining it sitting, now would be a good time to check for drain problems. Go to Harbor Freight and get you a AC/DC meter for under $25 or so. http://www.harborfreight.com/ac-dc-d...ter-37772.html Make sure it has DC amps draw, DC voltage, resistance and AC voltage. Key off. Remove the negative cable off the battery. Set meter on DC amps. Hook the meter lead to cable and the other to battery. !!Key off..do not turn on!! Ignore that first draw as the alarm trims back and stuff charges for 1 minute. Now,how many milliamps (mA) is it drawing? It should be no more then 6 mA which is the ECM (1), speedometer (1), tac,TSSM (1),HFSM (1) and voltage regulator (1)

When a battery wears out, a good charge will show fairly good voltage, but the battery can still have very low amperage capacity which will show in the crude crank test above, but it really should be checked after a good charge by removing it from bike and getting a free check at a place like AutoZone that has a fancy load meter check that gives you a print out of the battery health. Battery MUST BE CHARGED to check it. Be sure they set their meter to correct cold cranking amperage stated on the battery. Never charge the AGM absorbed glass mat battery with a regular car battery charger unless it is a newer one that says safe with this type of battery. Also, by taking battery out you now know you have good connections. Vibration tends to loosen the connections or a little corrosion will prevent charging or cause starting problems. Be forwarned, these checks quite often are incorrect due to the low amperage of these small batteries and junk checking equipment. If bike is charging , no load on battery when key is off and you are still having problems…REPLACE THE BATTERY. If battery is more then 3-4 years old.. REPLACE THE BATTERY.

Using the maintenance charger can get more years from a battery but be careful here. You do not want the last start 5 miles from home. If it still grunts when you first hit starter or kicks back with a bang, replace it. After a few years, charge and pull battery and have it checked for cold cranking amperage ever spring. Even then, if it grunts most ever start, I would replace it. Most battery checkers at AutoZone and places like that do not do really well on the low amperage setting on small batteries. Not sure why but they tend to say they are OK when they are weak. If they have one that fits your bike, Wal-Mart's AGM absorbed glass mat battery is just as good as any for one third to half the money of a Harley Battery. Do not put an old fashion one with vent tubes on a modern TC Harley. Do not jump, push start or run bike with a half dead battery except in a real emergency. If a bike battery is down and you jump it, throwing all that amps to it from a big car battery especially one that is running can wreck a bike regulator or charging system. Charging a worn out battery can kill alternator stator or the voltage regulator or both. Probably ending in a big dollar repair in parts alone.

It is also a good idea to always check your battery at 2000 RPM with your meter set to AC. If by chance, the regulator goes bad, sometimes it will let AC come thru. That is a sure sign of a bad regulator. Older 2 wire stators have a single phase output while the newer stators with 3 wires have a 3 phase output. The 3 phase system provides a more consistent and higher current output to the voltage regulator. The voltage regulator takes the AC from the alternator, rectifies it to DC and limits the voltage level to the battery depending on the voltage reading it gets back from the battery.

Also remember, when starting a Harley, hit the starter and hold it in till it is firing on both cylinders and running before letting up. If you let up before it’s running, quiet often, it actually take an FI motor longer to start. There is a fraction of a second more for a long stroke Harley then a multi-cylinder car for it to get going. If you do not do this, it will kick back with a bang, sneeze thru the intake or crank a lot longer the second time or shame on you the third time. Also, if you have a habit of doing this, the starter solenoid switch contact will only have half the life it could. You cannot hurt the starter. The starter gear has a sprag clutch. There are drive pins in it that as the gas motor catches and run, it outruns the starter motor drive and disengages it from the electric motor. If you hold it in a little too long and listen carefully, you will hear the sprag clutch run up the ramps and slip. Makes a sizzle hum. This will show you your starter sprag clutch is OK.

 

Okay charged the battery for about 4 hours. Took it to Advanced to gt checked. It only showed 9 volts and 0 cold cranking amps.

 

Headed to Laconia one year, I pulled over for a smoke, went to start it (05-FLHS)
and got the dreaded click click. I got a push start and rode the bike 40 miles to the
harley shop no problems. This was a carbed bike though. I think running a bike like
this does put a strain on the stator. I was willing to risk it that one time, but
I wouldn't ride the bike too far on a duff battery, it could get very expensive!