my buddy has a 74 ironhead that runs like crap when he turns the lights on. The battery was just replaced so im assuming it's a problem with the generator. can anyone recommend a place to get them and a roundabout price?

 

First check battery voltage without lights on and then with lights, it should be more than 12,5 Volts when motor isn't running. Has bike original ignitionlock ? are ignitionkeys ok ?

Electric or kick start or both ? points or electronic ignition system ?

 

I doubt that the problem is with the gen.

Unplug the headlight bulb and try again. This will isolate if the problem is with the light and its direct wireing, or if it is somewhere else in the lights circuit.

Here are my notes for a thorough charging system check. Run thru this not leaving out any steps and see what comes up.

IronHead Charging System Checkout

You need a multimeter. The digital ones are best and can be had for less than $10.00. A voltmeter is a multimeter set to measure DC volts. An ammeter is a multimeter set to read DC current in amps. The ohmmeter section of the multimeter will test for continuity. Continuity means that current may flow between the two points.

I find alligator clip probes are much more convenient than pointer probes. Occasionally a pointer probe is better so i have a set of each.

When using a Multimeter, if the object fails a test, repeat the test ensuring that you have good connections with the meter probes, especially to a good ground.


1. Fully charge battery.

It is not good enough to put it on a charger overnight and assume it is fully charged. Some batteries will take 24 hours to fully charge. The way to know for sure is to do a specific gravity test [for liquid filled batteries], or to use an automatic battery charger.

I have heard that you should never use a battery charger greater than 2 amps for any motorcycle; that it is best to use between .75 and 1.5 amps. Best are the automatic chargers such as Battery Minder or Battery Tender.

2A. Cell test battery [not for maintenance-free batteries].

Remove caps from battery cells. Keep the red voltmeter lead on a terminal and insert the black lead progressively into each cell, far enough that it contacts the plates. You should get readings of 2, 4, 6, 8, 10 and 12 volts. If one cell does not contribute its proper 2 volts then that cell is dead and the battery is no good.

2B. Load test battery.

It is said that, with electronic ignition, you should never crank the engine without grounded plugs attached to the wires. For this test you should install an extra set of plugs into the wires and set them onto the top cylinder head fins.

Disconnect both spark plugs. Attach voltmeter leads to the battery terminals. Crank the engine for 10 seconds [no more!]. Observe the meter WHILE cranking. If it goes below 10 volts then the battery is no good. Alternatively you can buy an expensive battery load tester.

Bring the battery up to full charge again before proceeding.

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

With voltmeter connected to battery terminals check voltage while cranking. Then with voltmeter on battery cables check voltage while cranking. If voltage drop due to cranking [should not go below 10 volts] is different cables may be bad or there may be corrosion.


Here is another very simple non complex test you can do if you suspect that something is draining your battery when the key is off. This applies to bikes that have no digital instrumentation (like ironheads). Unhook your negative battery terminal. Touch the wire back to the negative battery terminal, there should be no spark when you do. If it arks and sparks (like a downed hydro pole in a rain storm in a horror movie) then something is drawing power when it shouldn't be.

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.

6. Generator Test #1: Residual Magnetism

Disconnect both the A and F terminal wires. Connect the +ve voltmeter lead to the A and the -ve lead to ground. Run the engine at about 2000 RPM. The meter should read at least 2.0 volts. If the voltage is low polarize the generator and repeat the test. If the generator fails this test it must be disassembled for repair.

7. Generator Test #2: Maximum Output

Remove both the A and F terminal wires. Connect the +ve voltmeter lead to the A and the -ve lead to ground. Run the engine at about 2000 RPM. MOMENTARILY [not longer than 10 seconds] connect a jumper lead from ground to F and read the meter. The meter should read 25 to 30 volts DC. If the generator fails this test it must be disassembled for repair.

8. Here's a good way to bench test your generator:

1. connect a jumper from the "+" battery post to the "A" armature terminal on the gen.
2. Connect a jumper from the "-" battery post to the "F" field terminal of the gen.
3. Now take a third jumper from the "-" battery post and touch it to the case of the gen.

If all is well the generator will run like an electric motor. With the gen gear pointing away from you the rotation is clockwise.

Don't try this with the generator on the bike.

9. Polarizing the Generator

With the generator fully installed in the bike, all connections made, ignition off; connect one end of a jumper wire to the gen A, and momentarily touch the other end to the battery +ve terminal.

Usually [but not always they say], you will get a spark at the battery terminal and a light clunk sound from the gen.

10. Polarizing the Generator - The Complete Story

1. with the gen on the bench
[i] jumper the gen A to batt +ve
[ii] momentarily jumper from gen F to batt -ve

Note: This can be done the other way around,
[i] jumper gen F to the -ve batt
[ii] momentarily jumper gen A to batt +ve

2. with the gen on the bike, wires not connected
[i] jumper from gen F to a good ground
[ii] momentarily jumper from gen A to batt +ve

Note: This technique is preferred over #3 because the good ground is better than relying on grounding the F thru the reg.
Note: As with #1 this can be done the other way around.

3. with the gen on the bike, all wires connected
[i] momentarily jumper gen A to batt +ve

Note: This is technically the same as techniques #1 and #2 as the F is grounded thru the reg.

4. For bikes with a mechanical reg [1959 to 1977]

Momentarily jumper between BAT and GEN on the reg.

Note: this is technically the same as all of the other techniques as BAT is connected to batt +ve and GEN is connected to gen A.

5. For bikes with a Cycle Electric Generator/Regulator

On the Cycle Electric DGV-5000 generators you have to remove the brush cover and touch a wire from the positive terminal of the battery to the positive brush lead of the generator to polarize it. You can't polarize the generator from the external terminals. (One of the terminals is the battery terminal, and the other has an internal diode.)
You have to try pretty hard to reverse the polarity on those generators and they rarely need to be polarized.

For clarification: Cycle Electric does have a voltage regulator (the CE-540) which looks very similar. It will bolt up to a standard Model 65A generator and has external leads which connect externally between the regulator and the generator.
The CE-500 bolts to a Cycle Electric DGV-5000 generator and the regulator is internally wired to the generator.
- With the CE-540 setup the generator can be polarized by running a lead from the battery + to the "A" terminal.
- With the CE-500 you need to polarize the generator at the positive brush lead.

11. Generator Brushes Assembly: Dismantle, Cleaning, Repair

1. The brushes holder and related parts can be dismantled without removing the gen from the bike. This is useful because, in my [limited] experience, if the gen light is coming on then one or both of the brushes is probably sticking. This can be easy to fix.

I am writing this from memory, not while doing it. I think i have the removal process right.

Remove gen end cap. Remove the bracket and brush cover strap. Remove the commutator end cover. There are 3 screws visible. Two just hold the brushes to the brush holder; these do not need to be removed. The third screw attaches a wire from inside the gen to the brush assembly. Remove this screw. Now the brush assembly can be removed.

Usually it is quite dirty in there so at this point i use a spray can of electrical contacts cleaner to clean up the mess.

The brushes will spring out of the brush holder. They must be each longer than 1/2 inch else replace both. Reinstall each temporarily and work them between thumb and finger to see if there is any binding.

To re-install brushes in holder use long twist ties from the kitchen. Pick out the twist ties after the holder is re-installed.

2. To remove the gen from the bike: Disconnect the wires from the A and F terminals; remove the two bolts from the gearcase side; raise the inner end toward the 11:00 o'clock position, lower the outer end toward the 5:00 o'clock position, and remove carefully.

For the rest you really need a manual. The FM is very good. It is usually not necessary to remove the gen drive gear - this requires a gear puller to remove. The rest of the gen dismantles quite easily.

Once opened up you can do more cleaning and inspection; again using the spray can electrical contacts cleaner.

The FM contains a number of tests that you can easily do once it is opened up: field coil test, shorted or open field test, grounded armature test, and open armature test.

The shorted armature test requires special equipment which a shop would have [a growler]. Doing actual repair may require special equipment such as a lathe, and perhaps experienced hands.

 

Points ignition, both kick and electric. He does use keys not sure if it's the original setup though. The battery was just bought last week. Still gonna check though

 

Old/bad ignition switch might cause this, usually they broke so that lights are flickering...but it can cause also ignition problems. You can test this by bypassing ignition switch.
It's also good to check that wires in handlebar ( right side) aren't pressed by switch covers.

 

Just recently went through (from what you described) exactly what your friends going through! It nearly drove me f'n completely insane...

Anyway, here's (what fixed mine.)

Basically ur ganna use a fairly thick gauge wire a jumper/arc ur batt + to the + on your generator. U may even hear a click when this happens... Then do the same thing with batt - and jumper to gen -.

110. Polarizing the Generator

1. with the gen on the bench
[i] jumper the gen A to batt +ve
[ii] momentarily jumper from gen F to batt -ve

Hope this helps. Good luck

 

Ironmick.. finally got around to testing the generator how you said to. It spun like an electric motor so it should be good. Now It is backfiring really bad and hard to keep running. We're not really sure what the issue is because it wasnt doing any of this when he put the bike away for the winter. Could it be a timing issue? Would something cause the timing to be off during the winter? The carb has been cleaned and re-jetted and it is still running like crap. spark plugs and wires have been changed dont really know which route to take next.

 

i may be wrong but to me it seems you got a short somewhere that is using up your coil juice......that is if your generator is putting out eneough.how much does it show to be charging with lights off?with lights on?-----i dont see how your timing could have been affecyted just by sitting there and if its only screwing up when you turn lights on then you know it is electrical

 

I have never been certain if the "run it like a motor" test is aboslute. It the gen does not motor it is no good for sure. If it does motor then ... i am unsure if it is good for sure or if it just might be good. No one has ever resolved this for me on these forums.

runs like crap when he turns the lights on
Does [did] it run ok with the lights off? This could be coincidence, or as already suggested a wiring fault in the ignition/lights circuits.

It is backfiring really bad and hard to keep running.
This sounds like an electrical problem, current to the coil being unreliable or the spark plug firing irregularly for some other reason. One time i had this it was loose connections at the ignition coil. You could try a new set of plugs and/or wires. Next thing i would check is the wire from the points to the coil and the wire from the coil to the Run/Stop switch.

Here is a word description of the wire diagram for 1978 - mainly the same for your bike. You might start by checking any wires on the bike that are accessible, then work on the ones that you can access only one/both ends - mainly any that are part of the starting/ignition system.

One check is the "voltage drop check". If a wire has 12 volts at one end than it should have 12 at the other; a small drop off would be normal but a large drop off would indicate a problem. Another is a continuity check.

1[a] GREEN from generator F to voltage regulator
1[b] TAN from generator A to voltage regulator
1[c] TAN from generator A to BLACK at generator lamp

2[a] ORANGE from voltage regulator to connector, then ...
2[b] RED from connector thru MAIN cb to battery +ve
2[c] RED from MAIN cb to starter relay
2[d] RED from MAIN cb to ignition switch B terminal

Note: current passes thru MAIN cb in reverse direction along 2[b] to charge battery

3[a] RED from battery +ve to MAIN circuit breaker [same wire as 2[b]
3[b] BLACK from battery +ve to solenoid long stud
3[c] BLACK from solenoid short stud to starter motor

4[a] WHITE from ignition switch IG terminal [1st key stop] to IGN cb and ACC cb
4[b] GREEN from ignition switch L terminal [2nd key stop] to LIGHTS cb

Note: IG and L are connected by a small GREEN [sg]; at 2nd key stop both IG and L are 12 volts, even with sg removed. So, with sg removed anything connected to IGN, ACC or MAIN will come on at first key stop; anything connected to LIGHTS comes on only at second key stop - a simple, useful modification, especially so that the headlite is not on while using the starter motor.

Two BLUE from LIGHTS cb:
5[a] to rear wire harness connector then GREEN to tail light
5[b] to headlite dimmer switch and thru connector RED to speedo and tach lights

Two wires from headlite dimmer switch:
5[c] yellow to low beam
5[d] white to high beam and high beam indicator

Two ORANGE from ACC cb:
6[a] to rear stoplight switch
6[b] to ORANGE wire connector in headlite bucket

Four ORANGE from ORANGE wire connector:
6[c] to diode, thru connector to BLACK to oil lamp & gen lamp, and to a free spot in connector
6[d] to turn signal flasher
6[e] to front stop light switch
6[f] loops back into connector itself to service four free spots in connector

6[g] GREEN from oil lamp to oil pressure switch
6[h] GREEN from flasher to a connector, then two GREEN from connector to left and right turn signal buttons, then VIOLET and BROWN to left and right turn signal lamps

RED from rear stop light switch to rear wire harness connector
RED from front stop light switch to rear wire harness connector
RED from rear wire harness connector to stop lamp

7[a] GRAY from IGN cb thru headlite bucket to RUN switch

Two WHITE from RUN switch:
7[b] to ignition coil [12 volts when key and RUN are both on]
7[c] to START button [12 volts when key and RUN are both on]

7[d] BLACK from START button to starter relay [12 volts while START button is pressed] which results in ...
7[e] GREEN from starter relay RED 2[c] to solenoid small terminal
7[f] Solenoid activates, passing 12 volts along two BLACKs [i]from battery to solenoid 3[b] and [ii] from solenoid to starter motor 3[c]

 

ok it wont even start now. i would be able to get a reading from the volt meter on all of these wires with the bike off and key turned on.. right? And it was recommended to me to try and just replace the condenser and points. sound like a valid cause of the backfiring and poor running? I want to try and rule out all of the easy stuff before we take it to someone who knows what they are doing