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**TopCatGr58** · 05-19-2005, 06:15 PM

Hey Ben,

I'm no Electrical GURU, but if you'll look at the wiring diagram for the 79SF, you'll see that the headlight relay, the one where you spliced the hot wire into the Blue/blk wire has 4 wires. Black=ground, Red/white from fuse block, Yellow from Alt, and Blue/Blk to RLU. The relay should latch IF the yellow wire is truly generating enough voltage to throw the relay, and then it sends the power from the red/white into the Blu/blk. Since you bypassed the relay, and sent power to the RLU, you know the RLU is working. So... try that hot wire to the Yellow wire, and see if the headlight works. IF so. then the relay is GOOD, and you are NOT getting enough power from the Alt to trigger/latch it!

With your tach NOT working, really does sound like the ALT or reg/rect isn't working right!! Doubt that your tach is bad!

The oil pressure wire is linked to the red/blk wire going to the Light Checking Unit, which will light up in both situations, either a bad tail light, or the pressure sender possibly intermittently grounding. You're on the right track with checking the wire, but also check the sending unit, may be clogged and needs to be cleaned!? Keep at it!
T.C.

**randy** · 05-19-2005, 06:56 PM

What TC said.

Also, are you sure you're charging? If the REG/RECT isn't exciting the field coil, your ALT output voltage will be low vis a vis where TC was going, unable to latch the relay.

Note when you're testing, that the voltage at the yellow wire is an AC signal from the ALT, not DC so set your meter range switch accordingly.

**Shuriken** · 05-20-2005, 11:41 AM

Thanks for the quick responses, guys. I checked the regulator/rectifier by my crappy Clymer manual as well as the coils. I wrote down all my results but I am out of town presently and will have to post back with what I find after reading your replies.

From memory, the coils were 2.6ohms and 16kohms, and 2.6ohms and about 26kohms (arghhh) for primary and secondary windings. My scale was at 1kohms, so I couldn't set the meter where I wanted. My digital meter was more accurate but I could not get it to work consistently enough to believe the readings. It would blink a reading and then disappear. Temp was 80+.

When I tested the regulator function and charging system, both seem to function OK. I have a pretty new battery. Revving the engine raises the charging current, which is bled off at around >14 volts. I think the charging system is good. Manual says the regulator should bleed the voltage to ground above 14v.

From memory, the manual stated testing between wires (can't remember if it was regulator or rectifier) to see if there is either very high resistance or very low resistance when reversing the tester leads. That test checked out OK as well except for one wire, which if my memory is right, was like 1.8kohms. ??

For curiosity I also tested the ballast resistor while I had the meter out and I think it was also 2.6 ohms. I was also going to check valves and compression but I'll do that later. I find it's useful to have all of this data with a date on it.

So.... I'll test the relay as per your replies and hopefully will be on track for solving the problem.

How do I check the oil pressure sender? Is it under the carbs with the wire coming off of it? It looks like it would unscrew and could be cleaned that way?

As far as the tach goes, I have both 12v on one wire and 5~7 volts on the other, which is what the manual indicates. I would hope I don't have a generator problem but finding the true problem is the first step to fixing it.

She's a fast one. Compared to my 80g, she's a rocket. PSI readings and overall engine condition is much better. Plus the smaller rear wheel and less weight on the bike (4-1 aftermarket, no luggage rack, etc.). She'll bring up the front about 4-5 inches with a throttle snap down low and also gets front end light in 2nd gear. Pretty good for 6700ft elevation and carbs I don't think are dialed in on the mid range. So she has promise, but I have to get the electrics fixed so I can get her road legal.

Keep the replies coming. Thanks for your time.
Ben

**Shuriken** · 05-20-2005, 09:54 PM

TC/Randy:

Okay, this is what I found tonight as time permitted only a few minutes...

I spliced the 12v patch wire with an alligator clip to the yellow wire feeding the headlight relay. Sure enough, I could hear the relay work. The headlight doesn't come on but I can hear the switch work when I feed the yellow wire 12 volts.

I then removed the patch and cranked the engine over with the meter set to AC to measure AC voltage at the yellow wire. Since the carbs are dry (tank is removed) I couldn't start the bike to measure running voltage, but when it sputtered the output was up to 10v AC, and cranking was around 5 or so.

I don't know what AC output should be when the bike is idling, though.

Also, shouldn't the headlight only come on when the engine is running? So just forcing the relay to close by feeding 12volts to the yellow wire shouldn't turn on the headlight, right?

So right now I can say the relay is good and the problem could be elsewhere? That would mean my tach might also be good?

Voltage Regulator
I found my electrical notes from my testing the other day. Per Clymer, I tested the regulator voltage between the green and black wires with the key on and I get 12.5 volts. Clymer says I should have less than 1.8. However, when I run the bike, the battery voltage climbs from 12.5 to 14.0. So is my regulator bad?

Rectifier
In testing the rectifier, Clymer says resistance should be high or low depending if the tester leads are reversed - on all tests. All tested high or low except when the leads were between the red wire and brown wire, and I got a reading of 5k ohms on a 1k ohm scale. So is the rectifier bad?

I suppose when I get time I should test AC output voltage when the bike is running. If it's good, perhaps I should suspect a faulty voltage regulator/rectifier unit?

Is that what you guys would think after reading this?

Ben

**randy** · 05-21-2005, 01:13 PM

Dumb question - have you tested the headlight bulb? Also, sounds like your regulator is bad, you should not see 14V at idle at the battery. The voltage normally starts to rise above 13 at around 2500 RPM, and tops out at 14.5 at 3000 RPM and up.

Maybe, just maybe the higher than normal voltage blew you headlight bulb?

**Shuriken** · 05-21-2005, 02:09 PM

Hi Randy,

Thanks for the quick responses. The headlight bulbs are OK. I'll check charging current at idle again. I think 14v was when revving the engine.

Ben

**Shuriken** · 05-21-2005, 06:29 PM

I checked the yellow wire AC voltage with the engine running. When I rev it up (my meter is on the 15v scale) AC voltage goes over 15. Unless the generator is supposed to make huge amounts of voltage, 15+ volts seems reasonable to me. Can I assume it's not a generator problem, then?

That 15 volts is what I read at the yellow wire just before it gets to the headlight relay. Should the regulator be kicking in before voltage reaches the relay?

The headlight does not come on at any time unless I splice 12v into the blue/black wire.

Ben

**TopCatGr58** · 05-21-2005, 09:45 PM

Okay Ben,

Check the Red/white wire going to the relay...is there power on it? It's supposed to come directly from the fuse block HOT! IF no power, then check the headlight fuse! IF there is power, then the contacts in the relay may be corroded so that even when the relay trips, it's not connecting the red/white wire to the blue/blk to continue the circuit of power to the RLU!
T.C.

**Shuriken** · 05-22-2005, 09:16 AM

I checked the red/white wire and indeed, there is voltage from the fuse block.

Relay?

Thanks for all the help.
Ben

**TopCatGr58** · 05-22-2005, 09:24 AM

Okay....,

Disconnect that Yellow wire that comes from the Alt going to the relay. Use that other Jumper 12V and then after starting the bike, jump the Known hot jumper line to where the Yellow ALT wire connected to the relay, and it should trip the relay, and IF the lights come on, then you'll know that BOTH the relay is good, and that you're apparently not getting enough "something" thru that Yellow wire to trip it....and again, with those previous readings you stated with your reg/rect that it is most likely the suspect!? I've seen several on Ebay lately for $10.00 or so!
T.C.

**Shuriken** · 05-22-2005, 07:25 PM

Splicing in the 12v wire to the yellow wire when the bike is running did not make the headlight come on.

Rectifier/Regulator?

I also checked the oil switch. Not sure how exactly to test it but it didn't look gunky and I traced its wire under the plastic starter housing to its bullet connector - didn't find any problems there. Guess I won't get an easy fix on this stuff like I'd hoped. These danged electrical problems have taken away far more of my riding time than have mechanical ones.

Not to get off topic, but one of my coils mysteriously stopped working during my meddling. I retested them: one was 1.2 ohms / 15k ohms and the other was 1.1 ohms and 19k ohms. I wonder if 10 percent variance really makes them useless as the manual suggests.

Ben

**TopCatGr58** · 05-22-2005, 08:35 PM

Ben,

Since the headlights didn't come on with that HOT wire spliced to the Yellow, then it does sound like the RELAY is shot! As for the Oil Pressure sending unit, yes, it does just unscrew, and you can clean out the insides, carb spray, wire, whatever to get inside there and free up the part that is pushed up with oil pressure breaking the ground circuit!

As for your coils, the specs state 1.5 ohms, plus/minus 10% which is only 0.15, so range should be 1.35 to 1.65 ohms, you're under on both coils with this!!

Secondary 15Kohm, range 13.5 kohms, to 16.5 kohms! And these are NOT thru the caps, but high tension wire to wire only.

I've seen several relays on Ebay recently. Same for coils! But did you see my recent post about alternative coils from Mike'sXS?

BTW, for a handlebar grip, you might be able to find a bicycle one at Walmart, just to put a grip on the left side!?
T.C.

**Shuriken** · 05-22-2005, 10:15 PM

Thanks TC.

Yeah, I wondered about the coil readings. I used 3 meters and got different results each time, but I settled on the most reliable meter even though I originally planned to average all of the readings.

I would be curious to know what fellow XSives can measure in their own coils to see how far I'm off. I suppose when the old coils resistance goes too high the spark becomes weaker and weaker, etc. Until today they both produced spark - now one coil is dead.

I'll read your coils post after this.

At this point I am going to have to suspect one of two or both of the following things unless I can figure out a better test procedure:
1) headlight relay is bad
2) regulator/rectifier unit is bad
3) both are bad

Reasons for the above conclusions:
1) I get 12v dc on the Red/Yellow wire from the fuse box to the relay, which is good.
2) I got around 15v ac on the yellow wire from the alternator and 5-7 volts on the appropriate wire going to the tachometer
3) splicing 12v dc to the yellow relay wire when the engine is running does not activate the headlight
4) both headlight bulbs are good
5) I can operate the headlight by turning on the key by patching 12v dc from the fuse box to the blue/black wire
6) Testing the rectifier per my manual says tests should produce either high or low resistance - one wire gives a middle value.
7) another Clymer test, for the regulator, says with the engine not running but the key on, voltage should be less than 1.8dc. I had 12.

Reasons against the above conclusions:
1) splicing the 12v dc wire to the relay makes the relay click when the engine is not running (relay working?)
2) voltage regulator with engine running cuts voltage off when it gets above 14v dc.

Upon removal, I did use carb cleaner in the oil switch but I couldn't really find a way to know whether it worked or was clean.

Maybe if I replace enough parts something will fix itself.

At least cold compression at ~7000ft elev. is better than on my old 80g - cold psi was 125, 130, 130, 130.

Ben

**Shuriken** · 05-23-2005, 10:00 PM

Curios how my manual tells me my voltage regulator/rectifier unit should have a connector with 3 wires - gree, black, brown. Mine has just green and brown. No black. Testing the rectifier seems OK until I test between red and brown wires, which makes me question the rectifier. Also in testing the TCI unit voltage, all check out OK except for Black/White to ground, which should produce 6 volts and I get negligible voltage.

Ignition coil #1 quit working. I swapped coils and the same thing happens with a good coil. Plugged #2 coil's wires into #1 and I get spark.

So, I tried to find the headlight / tachometer problem and now I seem to have a whole slew of problems to which I see no solution.

If this keeps up I won't hesitate to sell her and get an FZ1. I've about had enough of electrical.
Ben

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