Another newbee with electrical problem.

I'm new to the motorcycle world, and I just got a 81 XJ750RH SECA I would love to put back on the road.

Infos :
Fuse box changed.
Motorcycle connected to a car battery.

When first turning the ignition switch the dash went on, with neutral & warning lights on.
I've tested the turning signals : they light on but don't blink: possibly dead bulb somewhere... let's go further...
Horns try hard to blow a sound, butt just 'clonk';
Having no headlight, I didn't try the light swithes.

Let's try the magical start button :
After a few hits on the start button, everything shut off. Since then, electrical blackout.

I've checked power the fuse box, and here is my statement :
key off : power comes to main fuse, not the 3 others 10 Amps : ok.
Key on : Power doesn't even come to main fuse anymore : not ok at all...

Any help would be highly appreciated !

 

One thing to check first. Is the battery hooked up correctly to the bike. If the battery is connected backwards the oil light should come on with the key off. Not trying to insult your intelligence but this is easy to do on these bikes. The cables to the battery have to cross each other in front of the battery to go to their respective terminals. I did it myself.
The turn signals may need to be cleaned of internal corosion. When they light up look at both front and rear lights and see if one is not lit. That will be the bad blub. If all light then start cleaning signals and connectors.

 

Howdy Amorican! From my schematic, you should see battery power at the main fuse feed. If you have lost this, you need to check out the line between the fuse box and the battery terminal. Corrosion or physical damage may be to blame.
Whereabouts in CA are you located? I've got an 81 750 Seca as well and I am rather familiar with the wiring. If you should need assistance, sing out!
Best of luck and let us know what you find out from your hunting session.

 

When the Battery is hooked-up backwards ... I would imagine any glowing warning light to be the very least of worries.


Check for Oil.
Check Alternator Brush lengths.
Check Starter for operating by jumping HT terminals on Solenoid.
Those horns aren't likely to make noise, again ... but there's adjustments on the back.
Unplug the Safety Relay and see if the situation improves.

Please keep us updated on this one.

 

Thanks a lot for your help !

BlueMaxim you were right, my battery was not hooked up correctly : I had a bad grip on the battery with the jumper cables.

Robert, I'm located in Mariposa, by Yosemite National Park.

RiCKoMatic, thanks for those hints. I'll give more news after I check everything.

By the way, the starter doesn't want to work anymore : I'm suspecting a blown up starter relay.
Let's hope I can still find relays at the dealer...

Thanks again guys. I'll definitively keep you updated.

 

Amorican, your just up the road (figuratively speaking). Should you run into trouble, holler, I'd love an excuse to head up that way.

 

If, as you say ... it all goes dead when you hit the start button ... I fear you are going to find that the Hot Starter Brush became one with that Commutator.

That's going to need an Electric Motor man or a replacement Starter.

At least you're "On the case" ... and have an idea where to look for what's causing you the trouble.

 

Checking done.
Some welding done on the ignition switch wires.

My actual statement :

- Starter is Ok; works fine when directly hooked on battery.

- Starting circuit cut-off relay Dead.
- Relay located under the AC ignitor missing. (Name & function unknown)

Any suggestion on what would be the easier/cheaper/quicker to replace those relays ?
Dealer, Online store, other...

By the way, After my inspection, I'm wondering about the coils wires order.
I understood from the manual -Left coil : left wire go on cylinder n°1, right wire on n° 4, right coil : left wire on n°2, right on n°3 . Am I right ?

 

yeap that's how they go!

 

AC ignitor? I'm puzzled as to what part that is. Are you referring to the TCI box perchance?

 

The missing relay is the Safety Relay.

No wonder!

 

Seems that Ac ignitor = Ic ignitor when I'm tired.
And you are right about what it is : even the wiring diagram calls it the TCI box...

Some automotive relays seem to have the same size. I was wondering if they could be a decent replacement... what do you think about that ?

 

You'll have to - "Play with it" a little bit.

The Yamaha Safety Relay is configured differently from a "Generic" Yamaha Relay and the popular ones made by Bosch and others.

You'll need to get it wired-up to Close when the Side-stand is up ... and Open when the bike's in gear or the Side-stand is down.

If the bike won't start unless it is actually IN Neutral ... that's the clue that it ISN'T wired-up right, yet.

 

No, a common relay won't work. The internals are a bit different but enough that you don't want to plug a standard relay into it. For the flasher, no problem but all the rest should be direct replacements only. If you still have the relay, you might be able to salvage it. If not... I could rummage through the pile of harnesses I have and see what lives in there.
If your starter/cutoff relay is still around, pop it open and see what colors are growing inside (Yamaha hadn't gotten a clue yet, the relays off our XJ's are all easily invaded by moisture). Clean with alcohol, blow dry and test.

 

Ok. Rick I think I'm getting the idea.
To me this means that 5 points relay would work.
Tell me if I'm wrong.


Robert, thanks for your offer, I sure appreciate. If the 5 points relay idea doesn't work, I will consider it. Please Give me a price.

 

There's only 4 Blades on the relay:

The standard relay is close to this:

+ - +
* - *

The safety relay is close to this:

* - +
* - +

If I have too ... I'll pull mine and map it.

That's something I already did in another thread ... but I can't find it.

The MAJOR problem with having the wrong relay in there is this:

With the IGN - ON and the Bike IN Gear and the Clutch Lever PULLED
Nothing happens.

But ... with the IGN - ON -- IN Gear and Lever RELEASED ... Pushing the START Button will ENGAGE the Starter and the Bike will Lurch forward or even START.

Very dangerous.

 

I gotta find one first. A new one is about $70 online. Got to pull the unit I have off the bike and pull numbers then root through the pile and match up. And this will get done when???
The 5 point relay you mention, it is Normally Closed in one position and Normally Open in the other correct? If you know which of the wires go to which circuit, you could swap wire positions on the connector to create the system you need. Good idea. Just be certain your switching the right wire to the right circuit or your still sitting there.

 

It seems that you won't finally have to look in your harness nest.

I've got already two 5 points relays, I'm working on adapting them :
Here is the information I've gathered, in case it could be usefull to anyone.
The automotive relays seem to be supposedly almost standard. Sort of...
Each wire points must face each other.
Each point should also have a number ingraved.
85 & 86 are for the switch wire, the one who will trigger the relay.
30 beeing the power entrance,
87A the closed relay power output,
87 the open relay output.

87A should be in the center of the relay.
30 should be oriented differently than the others.

 

Way to go! Incidently, on a lark last night I looked up the starter relay on BikeBandit and they offer it at just over $30. Just an option should things not go according to plan.

 

Do I need to pull my Safety Relay and map it for you -- Robert?

Would it help you design a work-around to make a generic relay be substituted?

 

May well be. Let me pull out my schizmo and look it over. This shouldn't be that bloomin' hard, especially if we put our collective minds to it. I'll get back to before the weekend.

 

I hear the starter krank again after the 5 points relay connection and some relays mixing.
It's kranking in neutral, stand down, clutch not pulled.

Now, there is no spark.
I'm wondering if the relays could not give the right signal to the tci in order to give a spark.

I'll read the threads on the forum to see if I find something usefull.

 

Unplug the Safety Relay and see if the bike Starts in Neutral.

 

I'm sorry fellas, I have not been able to give this issue much of my time this week. I haven't forgotten it.

 

The YAMAHA Safety Circuit Schematic Drawing for 650 / 750 Bike appears on pages # 242 - 243 in:

Haynes
Yamaha XJ 650 & 750 Fours
653cc - 748cc. 1980 to 1984
Owners Workshop Manual
Haynes # 738

IBSN 1 85010 353 4
Haynes Publishing 1994

 

Hello guys !
Sorry for my lack of news, I'm quite busy on some familial stuff.
The electrical troubleshooting will have to wait until this week end.
I shouldl have some updates at that time.

Thanks again for your help !

 

Hi again!

I'm back after a long month of absence.

With another set of relays, I've been able to hear the starter again.

I've put some gas in the carbs and tried to start the Xj, and connected the battery wires backward...
I know, I've been warned with the first reply.... But still, I did it.

Now, nothing happens when I turn the key. I'll try to check what I've killed this afternoon.

 

I would suggest to you ... that you find yourself some RED Paint ... and place a Painted Safety Reminder on your Battery.

Considering your having been warned NOT to hook-up the battery until you were sure it was not done wrong ... I am quite sure that everyone who learns of your hooking-up the Battery backward, will have a strong reaction; and that the reaction will not be one of amusement!

That you are able to "Check what you may have killed this afternoon" may very well be a short list.

But, considering that "YOURSELF" is at the Top of that List ... you should be grateful you have the checking to do.

Paint your Battery with a Safety Marking so that you don't make this dangerous mistake; again!

 

Rick, I had no clue this coud be THAT dangerous to invert polarity.

All I can say to defend my case is that it's not on the motorcycle side the mistake has been done.
I'm working with car batteries right now.
I've had to put back the battery I initially used on the car it belonged to, and found another one for the motorcycle purpose.
My mistake is that the lead connectors are switched compared to the first battery, and I did not know that could happen. I've jumped the wires the way they previousely went.

Doesn't change anything to my responsability though.

 

Ouch! Have you checked your fuses? Did you fry the rectifier or the TCI? Inquiring minds want to know!

 

its not dangerious,it may fry some elct componets but a battery doesnt care,years ago almost if not all vehicels was pos ground,the danger is hooking up 2 batteries together wrong when jumping,and I'll tell you something else almost everyone who has worked on stuff has done it at least once even if they dont admit it,usually no harm comes from it as long as you dont turn anything on guess you wasnt so lucky

 

I've seen bikes with NO wiring harness left ... that darn-near caught fire ... for just having Jumper Cables hooked-up backward for a moment.

If you escaped having something melt or fry you're the luckiest guy in XJ-Ville this month.

(Best thing that ever happened was having that Circuit Breaker Open on the new battery Chargers when they are hooked-up azz-backward.

 

I think I can compete for the "luckiest guy in XJ-Vill" this month.
I burned one fuse. I still have to check the rectifier, but eveything else is fine.
The turn signals came back with a new relay.

I can hear the starter again, so I'm fianlly back to the spark problem.

I've got some reading to do, try Rick's trick about the safety relay and I should be back soon.

Thanks again for your help.