All the warning lights are on (Seca 750)

I hope this is an easy one...

I just installed a Maxim engine in my Seca 750 frame. I hooked up all the wire harnesses in what appears to be the correct connectors. The turn signals work, the engine starts up and sounds good... The problem is that all the warning lights are lit on the dash. So have I over looked a connector somewhere?

Other things i noticed: the neutral light does not come on when the transmission is in neutral, and I can start the engine while it is in gear with the clutch engaged.

As always - thanks in advance,
Rustee Gold
1981 Seca 750

 

The warning lights will all come on as part of the initial self-check, and remain lit until you start the engine. If yours are still on after the engine starts (sounds like that is the case) then you probably forgot to hook up one of the connectors in the headlight bucket.

 

In order for the CMS to switch from a standby state to an active state one leg of the AC Generator must become active to initialize the CMS. This same leg of the AC Generator is also used by the head light relay. So be sure the 3 prong connector from the AC Generator stator is properly connected to the main harness as well as the two pin connector from the rotor.

Does the head light illuminate when the bike is started?
Is the red warning light flashing or just a continuous glow?

Not sure about this one but would be curious if the starter will engage with the side stand down. Normally, it requires both for the starter to engage in gear. The clutch lever pulled in AND the side stand up.

 

The engine is running but the CMS never activates. So I checked the voltage at the battery while the engine was running... I got 12.24 volts. Revving the engine to 2500 did not change the reading - still 12.24 volts. So I checked the resistance between the 3 stator wres: 1.1 ohms for all three. The rotor wires measured 160 ohms. Seems like a lot. I checked the rotor and stator resistance on the engine I removed and got 1.0 ohms between the stator wires (All three were the same) and the rotor wires measured 36.6 ohms. Still too high. However, the stator was charging fine in the engine I removed.

I see the shop manual indicates the stator resistance should be .46 ohms and the rotor wires should be 4 ohms.

So do I need a new rotor? New stator? Can I just pull the stator and rotor from the old engine and put them in the Maxim engine? Can these things be rebuilt?

Do I need to do more testing?

Rustee

 

Did you make sure that all of the plugs are connected, and to the correct plugs? There are two connectors in the headlight bucket that can be plugged in to the wrong sockets (reversed).

 

I didn't open the headlight bucket - ever - until today to check the wires and the fuse that's in there. So I'm sure that those plugs are connected correctly.

Regarding the rotor... I seem to remember having used a pencil eraser to do something a few years back... does that sound familiar? Can I somehow clean it up and reduce the resistance?

 

The stator is likely OK as it is hard to measure that low resistance with a DMM. The best you can do is touch the leads together and subtract that number from the actual reading.

The field coil (rotor) is way too high, which indicates a poor contact between the brushes and copper rings on the rotor. You can try cleaning them with a hard eraser, but should also check the length and condition of the brushes.

Compliments of Len from the Information Overload Hour:

https://www.xjbikes.com/forums/threads/the-information-overload-hour.27544/

"If your charging voltages are too low, suspect the alternator brushes first, then perform the alternator stator and rotor checks as described in the Alternator Section elsewhere in the catalog. Alternator brushes should be replaced whenever they are less than 11mm in overall length......the factory maintenance interval indicates that you should expect to replace these brushes every 8-10,000 miles. Factory brushes have "wear marks" (scribed lines) on the brush to indicate their wear limit; these aftermarket brushes also have the scribed wear line. Overall length of these brushes are 17.10mm, with 9mm of length from the wear bars to the contact end of the brushes:"

 

if you used an 82 motor oil level sensor is the same style as the Seca. if you used an 83 maxim motor did you swap the oil level sensor as the 83 is not atari compatable. it works in the reverse way.

check your neutral switch see if you cut wire during assembly or forgot to put in on the switch. test switch to see if it has continuity to ground.
bike starting when clutch pulled in is normal

or bulb is burnt out.

 

I cleaned up the surface of the rotor. The contact pins were fine. Now the resistance is 11 ohms on the rotor wires. Still higher than spec but better than it was. Warning lights are all still lit when engine is running. Headlight is not on.

I found a white with green stripe wire that is unplugged... can't see where it should plug into. The wire it near the starter relay in a wire harness. See the picture. Anybody knows where it goes?

 

Trying again with the picture... where does this wire connect?

 

I think it's the battery warning light... right?

 

The battery sensor wire should be white with a RED tracer (you said green, but the picture looks like a red stripe?).

 

Yep. The only thing that will effect is that the battery warning will come on and flash. It won't cause the problem that you have.

You should change the alternator brushes. They can look fine, but might not be.
One way to make sure is to measure the rotor resistance at the copper traces, the resistence of the brushes, and the resistance of the brush pigtail separately.

 

My bad... The stripe is red, not green.

 

After a bunch of reading and some testing, here is what I know:

1) There is no charge coming from the stator wires when the engine is running. I checked the voltage and it was zero on all three white wires. I have another "working" Seca 750 and I measured the white stator wires to have about 7 volts each when I revved the engine. (Measuring with the positive lead form the DMM on the back side of the connector and the negative lead grounded.)
2) The rectifier/regulator is working fine. I know this because I swapped the regulator/rectifier with the other working bike, and the working bike worked with the swapped rectifier while the non-working bike acted the same as before - no voltage coming from the white wires.
3) When I have the non-charging bike running, I can hear a fast clicking noise coming from the Starting Circuit Cutoff relay (I think this is also called the "Headlight Relay"?) The Haynes manual shows a test on page 244 and indicates the coil winding resistance should be 100 ohms. Mine measures 106 ohms - I assume that's pretty close?... The fast clicking noise seems to match the frequency of the engine RPMs - as the engine speed increases the clicking inside the relay increases, and when engine speed slows, the clicking slows.

Tomorrow I plan on swapping the relays from the working bike to the non-working bike to see if that makes a difference.

I'm really out of my comfort zone here 'cuz I don't understand electricity all that well, but I think either the relay is not working right, or the power lead to the relay is not getting the proper voltage to make the relay work correctly...

Rustee

 

The only part that I can help you with is that the headlight relay and the Starting Circuit Cuttoff realy are not the same relay.
Make sure which one you are looking at.

The Ultimate Relay, Switch, Sensor, and Diodes Guide

[Edited for clarity]
Headlight Relay:

Location:

- on all 1981-83 XJ750 Seca models: behind the left side cover, below the TCI and Regulator-Rectifier unit.

All other models do not use a headlight relay.

Identification:
- small metal "cube" relay, inked 3H5-00 on the top face.
- has a yellow (yellow) paint mark on the bottom terminal connector block.
- normally open; has an internal diode.
- plugs into a connector shell which has the following set of wires going to it:

Harness connector wire colors:

- on all 1981-83 XJ750 Seca models:
* Blue wire with black tracer stripe
* White wire with blue tracer stripe
* Red wire with yellow tracer stripe
* solid Black wire

Starting/Ignition Cut-Off/Neutral Safety relay:

NOTE: all XJ700 models and XJ750-X models use a consolidated relay assembly (mounted under and to the rear of the fuel tank, on the wishbone frame triple-tube joint) which combines the turn signal flasher, the turn signal canceller relay unit, and the starter circuit cut-off relay.

Location:

- on all 1981-83 XJ750 Seca models: under the gas tank, in-between the frame tubes, on a welded bracket just behind the flasher self-canceller relay.


Identification:
- on all models except XJ700 or XJ750-X models:
- small metal (original) or plastic (replacement) "cube" relay, inked 4H7-00, 4H7-01, or 12R-01 on the top face.
- has no colored paint mark on the bottom terminal connector block.
- sometimes labeled or described in manuals and diagrams as a "clutch switch unit", a "neutral safety relay", or an "ignition cut-off" relay.
- normally open; has an internal diode.
- plugs into a connector shell which has the following set of wires going to it:

Harness connector wire colors:
- on all XJ550 all models, XJ650 all models, XJ750 all non-X models, and XJ1100 models:
* Red wire with white tracer stripe
* another Red wire with white tracer stripe
* Black wire with yellow tracer stripe
* solid Light blue (sky blue) wire

 

Thanks for the clarification K-moe... The relay I am referring to (the one that's making the fast clicking noise) is the cut-off relay, not the headlight relay. As long as the engine is running, that thing sounds like a zipper...

 

I imagine that's down to the voltage spiking and then dropping. Since you have a second bike, swap the stator from it (the stator comes out without needing to touch the rotor).

Go ahead and swap relays first, just because that's less work. Though your voltage readings from that stator tell me that it's not doing the job properly.

 

I swapped the relays... no change. The good relay installed into the bad bike has the same rapid clicking.
I swapped the rotor and stator... no change. No voltage coming out of the white wires.

When I measure the rotor resistance on the good bike I get 9.4 ohms. The rotor resistance on the bad bike is 9.6 ohms (used to me about 160 but I cleaned it up since then.) I know the spec calls for 4 ohms and I'm in the process of ordering new brushes foe Len, but I'm not convinced that will fix the problem.

 

The brushes are the only thing between the wires and the stator. If the stator (and rotor) works in one bike, but not the other, that seems to rule out the one component that hasn't been swapped out; the brushes.

 

Just to be clear, this is the relay under the tank inked 4H7-00, 4H7-01, or 12R-01 on the top face.

This should be close enough to at least partially work. Try turning the ignition to "ON" and place a thin feeler gauge approximately 1/8 inch away from the generator cover. Current through the brushes / field coil should produce a magnetic field that will pull the feeler gauge toward the cover.

This should be measured in AC volts, and the leads should be placed to measure phase to phase - white to white wires. Typical AC voltage is close to 11 VAC at idle and around 13 VAC at about 2K rpm with everything connected.

You can also check the stator output open loop by separating the stator 3 pin connector. The voltages should be much higher and will climb rapidly when the engine is revved.

Idle of about 1100 RPM = 18.5 VAC
Rev to about 2100 RPM = 30.5 VAC

And to check the condition of the regulator / brushes / field coil you can do as below. Note a failure in any one item indicating no current through the rotor would cause the charging system to fail.



And, just to throw something really strange out there since it is a new / used motor - is the rotor rotating when the engine is turned over? You would need to check that manually by turning the crank with the AC Generator cover removed.

 

I swapped the stator and rotor as a unit - the brushes came with the rotor

 

Replies to Rooster53...

When I turn the key on and hold a feeler gauge to the alternator cover I can feel the pull of the magnet.

The relay is 4H701 (see picture).

I haven't done the DMM test yet but will do so tonight.

So why does the relay open and close so fast while the engine is running. I assume it's supposed to close as long as the starter motor is engaged and then open up after the engine is running... What would cause it to continue to open/close while the engine is running?

 

That relay is supposed to click once (engage) when you turn the ignition on, and stay that way unless one or more of the safety conditions are not met (The start/run GO conditions are: When starting; in neutral, or in gear with the clutch lever pulled. When running; in neutral with the sidestand down, or in gear with the sidestand up.)

That is the correct relay.

Rooster, you might have missed this from page one.

The only condition that I can think of that would make a good relay bounce like that is a low voltage condition (to just barely what's needed for the relay to close) or a cyclical voltage drop.

 

There are 2 red with white stripe wires on the relay. If I remove the relay and jump those two red wires, and start the engine, will anything bad happen? I want to test to see if things will work (like the CMS and the alternator). It might give me a clue...

 

So... at this point... I would prefer to just crawl in a hole and vegetate for a spell....

The short version is: the problem is fixed! The warning lights work and the alternator is working great!

The slightly longer version (and considerably more embarassing)... K-moe indicated there were 2 connectors in the headlight bucket that can be accidentally swapped... turns out there are 2 in the wire harness near the battery that have that same "feature"... it seems that if you hook the white stator wires to colored wires and the other colored wires to the other white stator wires... Well, you get my drift. I'm including 2 pictures... the first is how the wires were connected for the last week
The second picture... Well, the bikes runs pretty good now.

Thanks for all your patience. I actually learned a lot from your suggestions.

Rustee

 

Good job. You learned a new thing (and so did I).
Celebrate!!!