Last night I was out on the bike and a few times had problems starting the bike. When it was hot a few times it would clunk a bit when trying to get it to start and on the next attempt it would crank longer then usual but turnover after a few seconds. I put a new hd battery in less than a month ago figuring it was time but some of the issues I'm having now I had before the new battery. I checked with multi meter and here are some of the numbers I'm getting. My concern is once the bike is hot my voltage just does not seem right. At rest the battery is at 12.82. With the ignition on it is 12.24. At start up drops to about 10.9. At idle 13.44 and as low as 13.11 after about 5 minutes running. 14.08 at 3000 rpms. After running about 10 minutes at idle with passing lamp radio and front brake applied volts go to as low as 12.61. The starting clunks (not sure if that accurately describes it) was the first time it has happened since I put the new battery in but had did it from time to time before I replaced it. Any thoughts?

 

check your cables- tight ( both ends!), clean and no corrosion inside the insulation

here's my neighbors battery cable- I found this after he had spent over $1300 at the dealer replacing batteries, stators and voltage regulators



mike

 

What year is the bike?

 

Sorry about that. It's a 2008 FLTCHU.

 

Load test battery.
If ok
Check charging system.

 

Stator output?

 

check connections

 

There are two Stickies in the Tech Electrical section that will help you diagnose any problems. You will need a multimeter.

 

The poor starting may not have anything to do with the battery/charging system. But, it sounds suspiciously like the compensator is sending you a message that it's a piece of crap and needs replacing. Same symptoms as my 07 EGC with 50K miles last year. You're due on that issue with an 08.

 

May help..just my 2 cents..

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%
12.3 = 50%
12.0 =25%

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.
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. 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. 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 jump, push start or run bike with a half dead battery except in an emergency. Charging a worn out battery can kill alternator stator or the voltage regulator or both. Probably a big dollar repair. 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. The older stators with two wires is a two phase AC system. Lot of people call it a single phase but it’s two. The AC voltage you see appears single since you check it AC across the two wires since there is no earth ground. If you were to check one wire to an earth ground, it would show ˝ the voltage. Same with the other. Together they double and are two phase. The newer 3 wire system is a 3 phase AC system for the higher amperage output.
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. 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 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.