Checking coils, got a shock!

[frosty5011]

The coils don't look aftermarket. How shall I check?

Does it say anything on them? What color are they? Do the plug leads seperate unplug from the coils at the coil?

So far, all the 'stock' coils I've seen are either in a black casing, or a flesh/beige colored casing. On the stock ones, you cannot unplug the leads at the casing/coil.

 

[UncleMike]

Does it say anything on them? What color are they? Do the plug leads seperate unplug from the coils at the coil?

So far, all the 'stock' coils I've seen are either in a black casing, or a flesh/beige colored casing. On the stock ones, you cannot unplug the leads at the casing/coil.

They are off-white and say NipponDenso underneath them. It seems the wires are attached by some yellow goo.

I took off the tank and the airbox in order to get to the battery terminals. I turned the multimeter to DC20V and turned the ignition on, placing the red lead on the connection of the orange wire and the black lead on the negative battery terminal and got a zero reading for both coils.

 

[ScottMc1100L]

Great. One more freakin' thing. What do I expect for a $100 bike. At least she's pretty and I'm learning a lot.

Could be a cheap/inaccurate meter and or method of testing. Make sure you have CLEAN contact points and DON'T hold both ends with your fingers.

And don't **** on it while someone's cranking :lol: ...you guys kill me!

 

[t3rmin]

I took off the tank and the airbox in order to get to the battery terminals. I turned the multimeter to DC20V and turned the ignition on, placing the red lead on the connection of the orange wire and the black lead on the negative battery terminal and got a zero reading for both coils.

Hmm... that would mean you're getting zero voltage to the coils and the bike would not run at all. Try checking another point on the orange wire (it splits and one side of the "Y" goes to each coil, so you have a few different places to test). Make sure you've got some good metal to connect the multimeter lead to and scratch it a bit with the probe to get through any surface corrosion.

Also try putting the black multimeter lead on the engine block/head instead of the negative battery terminal just for kicks...

Unless your multimeter battery is totally dead or the meter is completely broken, you should get SOME voltage here. No multimeter is so inaccurate as to completely miss 12+ volts...

 

[UncleMike]

Hmm... that would mean you're getting zero voltage to the coils and the bike would not run at all. Try checking another point on the orange wire (it splits and one side of the "Y" goes to each coil, so you have a few different places to test). Make sure you've got some good metal to connect the multimeter lead to and scratch it a bit with the probe to get through any surface corrosion.

Also try putting the black multimeter lead on the engine block/head instead of the negative battery terminal just for kicks...

Unless your multimeter battery is totally dead or the meter is completely broken, you should get SOME voltage here. No multimeter is so inaccurate as to completely miss 12+ volts...

I tested it against my battery just to be safe and was getting 13.3v while ign. was off and 12.35v while it was on.

As for the coil, I peeled back some of the rubber guard and put the terminal directly on the connection at the coil. Should I be trying in another place?

 

[t3rmin]

Well I thought you said you were getting "zero reading" before, so I was worried. If you're getting greater than 12v with ignition on, then you're in good shape.

However, you should be getting zero, nada, nothing, with the ignition off. If the coils are getting power with the ignition off, then you'll eventually fry them, not to mention drain the battery.

*EDIT* When you say "tested it against my battery just to be safe", do you mean put both multimeter leads on the battery (ie: just testing the battery)? Or do you mean putting one lead (red one) on the orange wire and the other (black one) on the - (negative, black) battery terminal? I wrote the above assuming you had one lead (red one) on the orange wire and were getting 12.35v with ignition on.

 

[UncleMike]

Well I thought you said you were getting "zero reading" before, so I was worried. If you're getting greater than 12v with ignition on, then you're in good shape.

However, you should be getting zero, nada, nothing, with the ignition off. If the coils are getting power with the ignition off, then you'll eventually fry them, not to mention drain the battery.

*EDIT* When you say "tested it against my battery just to be safe", do you mean put both multimeter leads on the battery (ie: just testing the battery)? Or do you mean putting one lead (red one) on the orange wire and the other (black one) on the - (negative, black) battery terminal? I wrote the above assuming you had one lead (red one) on the orange wire and were getting 12.35v with ignition on.

Nope, I'm getting a zero reading when testing the coils. I tested just the battery to check and make sure my multimeter was still good.

 

[Billy Ricks]

Billy - that value is while checking with the plug caps on, right? If he was checking without plug caps (-10k for the set), AND his coils are aftermarket, then he would be OK....on the low side, but ok.

Sounds like stockers so the resistance is low.

You can usually get late model replacements from Kats and Bandits off Ebay for $30 or so that work just fine.

 

[Billy Ricks]

Here's a set of coils from a '99 that will look very similar to the old stockers.
http://cgi.ebay.com/ebaymotors/99-B...004QQitemZ140035443770QQrdZ1QQsspagenameZWDVW

 

[t3rmin]

Well obviously the bike is running (isn't it?), so there has to be voltage to the coils. I'm not sure what to tell you. I suppose the colors could be different on your bike. Regardless of what color, we're talking about the wires that feed the coils. Not the plug wires, but the wires on the other side of the coils. There will be two wires to each coil. Hold the black meter lead on the neg battery terminal and put the red lead on all of the wires going to the coils (one at a time). With the ignition on, one of the two wires going to each coil should have voltage.

If you're disconnecting the wires from the coil before testing them, make sure you test the correct side. If you test the coil side after it's been disconnected you won't get anything. If you test the other side (the side coming from the wire harness), it'll still work. I just tested mine without disconnecting anything by jamming the lead under the rubber/plastic sheath until I hit metal. It sounds like you're basically doing that, too, but I just wanted to make sure...

 

[UncleMike]

Well obviously the bike is running (isn't it?), so there has to be voltage to the coils. I'm not sure what to tell you. I suppose the colors could be different on your bike. Regardless of what color, we're talking about the wires that feed the coils. Not the plug wires, but the wires on the other side of the coils. There will be two wires to each coil. Hold the black meter lead on the neg battery terminal and put the red lead on all of the wires going to the coils (one at a time). With the ignition on, one of the two wires going to each coil should have voltage.

If you're disconnecting the wires from the coil before testing them, make sure you test the correct side. If you test the coil side after it's been disconnected you won't get anything. If you test the other side (the side coming from the wire harness), it'll still work. I just tested mine without disconnecting anything by jamming the lead under the rubber/plastic sheath until I hit metal. It sounds like you're basically doing that, too, but I just wanted to make sure...

Yup, that's exactly what I'm doing. Guess I'll just keep trying.

 

[t3rmin]

Make sure the kill switch is set to run, too, not just the key.

 

[UncleMike]

Make sure the kill switch is set to run, too, not just the key.

That seems to have accounted for it.

9.7v on the left coil
9.9v on the right

I told you to treat me like a complete moron. Seems a bit low to me, eh?

 

[t3rmin]

Ahh ok, now you've got it! ;-)

Voltage is too low, though! You're in the same range (actually a little lower) I had when I was having a bunch of trouble. And the voltage may even be getting worse once things heat up (sometimes questionable connections get worse with heat). If you can't go through the wiring harness, ignition switch, and kill switch, and clean up the connectors enough to get 12+ volts, install a relay with a direct wire from the battery like I did. Made a HUGE difference.

You *need* to have 12+volts to those coils!

You'll find relay(s) at the auto parts store in the lighting/electrical section. It'll look like a small box with 4 or 5 prongs coming out of the bottom. Open up your car hood and look in the fuse/relay box for an example. The relay install took me about 30 min. and I'd be happy to walk you through it if you go that route.

 

[UncleMike]

Ahh ok, now you've got it! ;-)

Voltage is too low, though! You're in the same range (actually a little lower) I was when I was having a bunch of trouble. And the voltage may even be going down for you once things heat up (sometimes questionable connections get worse with heat). If you can't go through the wiring harness, ignition switch, and kill switch, and clean up the connectors enough to get 12+ volts, install a relay with a direct wire from the battery like I did. Made a HUGE difference. You *need* to have 12+volts to those coils.

You'd recommend this rather than buying new coils?

I'm assuming if corrosion in the ignition switch and kill switch are robbing me of voltage, it's going to be the same issue even with new coils, right?

Would that entail just taking apart the right hand control and cleaning it up?

As for the wiring harness, what exactly am I cleaning? I've been wanting to clean all my connections of corrosion and slap some dielectric grease on there for some time, but I could never get a good enough step-by-step to figure out what it is I'm trying to clean.

 

[t3rmin]

New coils won't help you with the voltage thing. You may *also* have bad coils, but I'd worry about getting 12+v there first and seeing how it runs.

To clean connectors start in the back by the regulator/starter/fuse block, find every connector, pull it apart, spray WD-40 in, and put it back together. Dialectric grease would be good also. Tug on every wire in the plastic multi-connectors (if it comes out easy, redo it) and twist every "bullet" connector around good to scrape off corrosion. Any burnt/melted connectors should be replaced. Do the same for all the connectors in the headlight bucket. Also pull the fuse block off and clean all the connections in the back. Replace the fuses, even if they look good. Rip into the ignition (key) switch and kill switch and clean/grease everything.

This is alot of work to do correctly. I didn't even bother to tear into the ignition and kill switches and do a super thorough job. I just did a cursory cleaning of connectors and replaced all the burnt ones I found. Then I just went the relay route since it was much easier and I felt more comfortable with a nice solid direct wire from the battery to the coils.

The relay is just a switch. The "trigger" to the switch is the original orange wire. It (the relay) completes the circuit of the direct line from the battery to the coils only when it sees voltage on the original orange wire. That way you bypass all the old shoddy wiring but the coils are still only powered when the ignition is on.

 

[svahnm]

I felt more comfortable with a nice solid direct wire from the battery to the coils.

That is what I did also for my gs850g after many inexplicable running problems. I managed to suspect also carburetors, valve clearances and vacuum leaks etc...

I even tried to clean connections and switches twice including key switch. Somehow voltage dropped always. I could not ever find the place with bad connection. (I should have used testlamp instead of multimeter, because only on heavy load bad connection would show up)

Finally I jumped temporary wire (with fuse) from battery to coils. Same time I also installed a new battery, plugs and caps - the problem was gone!

Symptoms were so wierd! First cylinder 2 was failing (cylinder 3 occassionally too).
If I removed plug caps from 1 and 4 THEN cylinder 2 worked fine! Now, I know it was just not enough to fire all 4 cylinders properly. EDIT: FYI: I swapped each other coils, wires, plugs and everything but symptom did not move from cylinder 2 anywhere.. That was what made me desperate and think of carbs and other non-electric related.

Meanwhile I even changed to electronic ignition and new coils from the breaker points ('79). The problem was gone for a while until voltage dropped enough again. It happened so many things that afterwards it surely looks obvious, but when problems occured and pinpointing did not make clear answer I was too confused..


UncleMike, relay controlled extra feed to the coils is better for long run (or new wire harness), but in the beginning if you don't have spare relay at home you could just test it with temporary wire straight from battery. Just be careful not to ground accidentally that hot wire anywhere.

 

[bonanzadave]

Mike,

That voltage at the coils is exactly what I get and mine runs AOK. I think your ok there, but if the relay add on worked for others go for it. With voltage at the coils we have Identified a NON-CDI system. Make sure you have 3 ohm Non-cdi coils. The Accel web site offers good troubleshooting tips. Good Luck. The Accel coils you need are 140403 (NON-CDI)

http://go.mrgasket.com/InstructionSheetsList.aspx?BrandID=9

Did you put the new spark plug caps on ?

 

[t3rmin]

That kind of voltage may or may not work depending on whether it gets worse when hot, the condition of your coils/wires/caps/plugs, the tuning of your carbs, etc. etc. Also, aftermarket coils may still be able to generate more of a decent spark with 9+v than stockers.

BUT, you will _never_ get as hot/thick of a spark with 9+v as you would with 12+v. Buying Accel coils will not fix the problem. It may or may not cover it up, but the fact remains you've got some crappy wiring somewhere in your ignition, which is not something I'd ignore!

Svahnm gave some good avice. If you want to see how it'd run with the relay trick in place, just temporarily run some wire direct from the battery to the coils (just use some wire nuts to connect the wires). This isn't a long term solution since you don't want to power the coils while the bike is off, but you can see whether or not it'll make a difference.

For my money, once I saw low voltage at the coils, there was no question whether I'd wire up a relay if I couldn't get it cleared up by cleaning connections. Even if it's not causing problems now, it'll just get worse as time goes on and you _WILL_ be impacted by it in the future if you don't fix it now.

 

[UncleMike]

Don't worry, guys. Any job worth doin' is worth doin' right.