Ironhead runs great cold, dies when hot?

[Tat2Neil]

*edit for future readers: it ended up being a frayed/split wire from the generator to the voltage regulator under the bike and a faulty voltage regulator)

I picked up another Ironhead to add to my collection, a ‘78, rigid, kick only, I’m assuming 6 over forks but haven’t grabbed a tape measure yet, and a hell of a rake.

While I was riding it home on surface roads with moderate traffic, it ran flawless the first 30 minutes, but about 2 miles from my destination as I came up to a stop light it started to cut out, gave it some gas and got to the next light and it died as soon as I let completely off the throttle. Couldn’t get it started and had to push it too a gas station through the stop light.

Tried kicking it over about 50 times and she never even coughed or sputtered. And I noticed my headlight was dim, super dim, just a orange glow on the filament.

Fast forward after getting picked up and bringing the bike home 2-3hrs later in my shop I turned the key on, headlight was bright again, 2 kicks and she fired right up. And This morning, fired on the first kick, ran and idled just fine.

So before I get myself stranded again I’ve been searching for a solution. I’ve read about voltage regulators going bad and causing funky things once the bike heats up, but would that explain an apparent loss of electrical power (dim headlight) that corrects itself when it’s cooled down?

I’ve also read about the coil causing similar problems if it’s going bad, but I don’t think that explains the dim headlight.

Could it be the battery itself?

I know the bike has sat for a couple months.

Thanks in advance for any input. And here she is, aside from general cleaning, probably a new paint job on the tank at least, then i’ll probably just pinstripe some stuff and call it a day and put some miles one it!

[TriNortchopz]

Sounds like there is something causing the battery to drain with ignition on. The battery recovers with ignition off allowing you to restart it. I would have a light switch so the lights are not on when starting it; start it, then turn on lights.

From
IronMick’s Complete Guide to Troubleshooting Ironhead Electrical Problems

Follow this procedure carefully. Do not leave out any steps …

IronHead Charging System Checkout

You need a multimeter
1. Fully charge battery.
2A. Cell test battery [not for maintenance-free batteries].
2B. Load test battery.

3A. Current Drain Test #1

Disconnect the battery -ve cable from the battery. Connect the ammeter between battery -ve post and the battery cable. It should read .003 amps or less.

3B. Current Drain Test #2

Disconnect the +ve terminal from the battery. Connect an automotive test light between the battery and the cable. If light comes on there is a current draw.

Note: To determine which circuit is faulty disconnect the circuit breakers or remove the fuses one at a time. When the light goes out you know which circuit is the problem.

3C. Battery Cables Test

4. Charging System Test
Measure the battery voltage with the bike not running. It should be at least 12.x; preferably it will be 13.x.

Measure the voltage with the bike idling at about 2000 to 3000 RPM. It should be at least 1.0 volts higher than the not-running reading, otherwise the charging system is not charging the battery. It should be at least 13.x, preferably 14.x.

5. Regulator Test
Disconnect the regulator. Connect your ohmmeter to the orange and tan wires. Note the reading. Reverse the connections. Note the reading. One reading should show continuity, the other should show no continuity. If the regulator does not pass this test it is no good. This is the circuit that prevents the reg from draining the batt when the bike sits overnight.
This test only tests one circuit in the regulator, so even if it passes this test it may still be no good. There are other tests of the regulator that require specialized equipment. These tests are in the factory and Clymer manuals. I recommend taking both the reg and the gen to an automotive electric repair shop for testing if needed. Note: these shops usually want to test both parts together.

See the full Troubleshooting guide here:

http://odenmotorshop.com/2013/12/ironmicks-complete-guide-to-troubleshooting-ironhead-electrical-problems/

[rockman96]

Could it be the battery itself?

Yes.
It could also be an intermittent short pulling the battery down... I once had an intermittent short near the steering head that drove me nuts for a short time. I take it you have only been out on it this one time, so there is no pattern established yet... But if'n I were a betting man, I'd bet that your battery is going south.

ETA: I had this reply mostly typed out before trinortz responded, but I was diverted and after I posted I saw he gave you a very good and thorough procedure.

[Tattooo]

Yep it could be the battery or charging system or both...

[Kdial85]

re adjust your pushrods and make sure they are not too tight, my old iron head did the same thing when I first got it. Also you can check the coil too.

[Tat2Neil]

Sounds like there is something causing the battery to drain with ignition on. The battery recovers with ignition off allowing you to restart it. I would have a light switch so the lights are not on when starting it; start it, then turn on lights.

From
IronMick’s Complete Guide to Troubleshooting Ironhead Electrical Problems

Follow this procedure carefully. Do not leave out any steps …

IronHead Charging System Checkout

You need a multimeter
1. Fully charge battery.
2A. Cell test battery [not for maintenance-free batteries].
2B. Load test battery.

3A. Current Drain Test #1

Disconnect the battery -ve cable from the battery. Connect the ammeter between battery -ve post and the battery cable. It should read .003 amps or less.

3B. Current Drain Test #2

Disconnect the +ve terminal from the battery. Connect an automotive test light between the battery and the cable. If light comes on there is a current draw.

Note: To determine which circuit is faulty disconnect the circuit breakers or remove the fuses one at a time. When the light goes out you know which circuit is the problem.

3C. Battery Cables Test

4. Charging System Test
Measure the battery voltage with the bike not running. It should be at least 12.x; preferably it will be 13.x.

Measure the voltage with the bike idling at about 2000 to 3000 RPM. It should be at least 1.0 volts higher than the not-running reading, otherwise the charging system is not charging the battery. It should be at least 13.x, preferably 14.x.

5. Regulator Test
Disconnect the regulator. Connect your ohmmeter to the orange and tan wires. Note the reading. Reverse the connections. Note the reading. One reading should show continuity, the other should show no continuity. If the regulator does not pass this test it is no good. This is the circuit that prevents the reg from draining the batt when the bike sits overnight.
This test only tests one circuit in the regulator, so even if it passes this test it may still be no good. There are other tests of the regulator that require specialized equipment. These tests are in the factory and Clymer manuals. I recommend taking both the reg and the gen to an automotive electric repair shop for testing if needed. Note: these shops usually want to test both parts together.

See the full Troubleshooting guide here:
http://odenmotorshop.com/2013/12/iro...ical-problems/

Awesome! This was exactly the sort of check list I was looking for, many thanks sir! And I agree, i’ll Probably wire in the same 3 position switch I did on my ‘99 so I can have Low-off-high. I need to add in a running light in the rear since it’s brake light only, and also a small license plate light. But first things first, figure out my battery draining issue!

[Tat2Neil]

Yes.
It could also be an intermittent short pulling the battery down... I once had an intermittent short near the steering head that drove me nuts for a short time. I take it you have only been out on it this one time, so there is no pattern established yet... But if'n I were a betting man, I'd bet that your battery is going south.

ETA: I had this reply mostly typed out before trinortz responded, but I was diverted and after I posted I saw he gave you a very good and thorough procedure.

I did try to take it around the block today right after my OP, and didn’t even make it to the end of my street before she sputtered out and died, and back to dim headlight and wouldn’t even try to start. Pushed her home and put the battery on the charger for 1.5hrs and barely had to push the kicker to get it to start, this was all before I saw everyone’s responses so i’m about to start running through the checklist. Thanks for the reply!

[Tat2Neil]

Yep it could be the battery or charging system or both...

I’ll let you know the final couplrit

[Tat2Neil]

re adjust your pushrods and make sure they are not too tight, my old iron head did the same thing when I first got it. Also you can check the coil too.

I plan on doing just that, but I think the current issue is electrical based and not the pushrods, but good advice none the less!

[farmall]

If you didn't personally wire it, go over the ENTIRE electrical system because many, many customs turn out to have been wired by drunk children. Besides the excellent advice above, SEE ALL the wiring. Fondle, caress and wiggle that shit. Know all connections are tight. Inspect any switches. They wear out and can become intermittent or even intermittently short to ground.

Test the battery (load testers are cheap and worth owning, they work on auto batteries too) and if the battery is old I'd consider replacing it even if it tests good. Those inspection bands on generators exist for good reason. Get a visual on commutator and brushes.

[Tat2Neil]

If you didn't personally wire it, go over the ENTIRE electrical system because many, many customs turn out to have been wired by drunk children. Besides the excellent advice above, SEE ALL the wiring. Fondle, caress and wiggle that shit. Know all connections are tight. Inspect any switches. They wear out and can become intermittent or even intermittently short to ground.

Test the battery (load testers are cheap and worth owning, they work on auto batteries too) and if the battery is old I'd consider replacing it even if it tests good. Those inspection bands on generators exist for good reason. Get a visual on commutator and brushes.

Looks like this is my next step, I hope I don’t end up re wiring the whole bike, but I’ve narrowed the problem down to something in the charging system. I’ve bench tested the generator and it worked, I bought a new battery to rule out that, but when I started the bike I put a volt meter on the battery and could watch it slowly drop, i let it idle with some occasional holds at higher RPM for 2-3 minutes and it dropped from 12.1 to 11.8 and it would never flucate with RPM increases. I assume it should act like a newer charging system and have a higher reading at the battery when it’s running?

[Tattooo]

I assume it should act like a newer charging system and have a higher reading at the battery when it’s running?

Yep your assumption is correct...... It ain't charging it should be around 14v, and if you keep running it and killing your battery you can take it back for another new one.....

[Tat2Neil]

Well a +1 for farmall.. I gave the bike my simple green and scrub brush treatment in preparation for a re-wiring, and once I crawled under it there was a big ‘ol fray that about smacked me in the face. It was the wire from the armature terminal to the voltage regulator. So a quick patch there and zip tied out of the way to keep history from repeating itself. Started the bike back up and still draining the batt. Long story short, after a few more tests and part swaps, discovered my voltage regulator had also shit the bed. Swapped in a replacement and was finally seeing + readings on the meter. Also noticed my headlight now brightens with revs, dims slightly at idle. Rode to work and had fully recharged the batt on the way. Thanks for the pointers!