Electrical problems and updates

[Keithh]

Greetings All,

Yes, I'm again with electrical gremlins. The bike ran fine for sevweral days, had it out for a nice ride (when the side cover was lost!), parked it in the garage yesterday. Tried to start it today, once again, no joy. Swapping the TCI box with one TC brought over didn't solve the problem.

A question: How much should the voltage drop at the battery be whike cranking over the starter? When I checked the battery, it was showing 12.7 volts. When cranking over, it dropped to 11.5 or so. Voltage to the CDI box (red/white wire) is lower still - maybe boarderline for what it needs to function. Wondering if the starter is drawing too much? Didn't have a chance to put on the kick starter to see if it would start that way.

Any info/ideas appreciated.

Keith

[tw1980]

Does it have spark?I assume it does not since you are looking for an electrical problem.But yes the battery voltage will drop while cranking.

[petejw]

Greetings All,

Yes, I'm again with electrical gremlins. The bike ran fine for sevweral days, had it out for a nice ride (when the side cover was lost!), parked it in the garage yesterday. Tried to start it today, once again, no joy. Swapping the TCI box with one TC brought over didn't solve the problem.

A question: How much should the voltage drop at the battery be whike cranking over the starter? When I checked the battery, it was showing 12.7 volts. When cranking over, it dropped to 11.5 or so. Voltage to the CDI box (red/white wire) is lower still - maybe boarderline for what it needs to function. Wondering if the starter is drawing too much? Didn't have a chance to put on the kick starter to see if it would start that way.

Any info/ideas appreciated.

Keith

hi keith,
'that small drop while cranking is normal,
if it drops to around 10 and lower while cranking then
the battery would need replacing.
what readings are u getting at the tci?
remove a plug cap or 2 and stick a spare plug in and earth
it to the head, are u getting spark while cranking?
if so then the problem could be fuel, when was the last time
the carbs were cleaned? theres a small port in the fuel bowl for the enricher that can
block and cause hard starting when cold.

[crazy steve]

...When I checked the battery, it was showing 12.7 volts. When cranking over, it dropped to 11.5 or so. Voltage to the CDI box (red/white wire) is lower still - maybe boarderline for what it needs to function. Wondering if the starter is drawing too much? Didn't have a chance to put on the kick starter to see if it would start that way...

The highlighted sentence is probably the key. The TCI needs at least 10.5 volts to work, so if you have poor connections in the system the voltage drops can add up, which if you're seeing a lower number at the TCI is an indication of that. The roughly one volt drop when cranking is normal, so the starter is very likely good. Go through all the connections and make sure they're all clean and tight.

This many years down the road, the electrical connectors in these bikes are a known trouble point.

[Keithh]

Thanks for the feedback! I'm sure it is spark related - I've been battling this for wayyy too long now. When the bike starts, it runs great, which makes me think it has to be something common for both coils. The coil voltage (red/white) appears to be good - matches system voltage. The fact that it runs great once started has me thinking the pick up wiring is fine (meter seems to confirm that). During cranking over the engine, the red/yellow from the solenoid feeds 11+ volts to the TCI, zero when cranking stops - as you would expect. I went so far as to replace the harness (cleaning the connections in the process). I've cleaned the right side handle bar switch twice - appears to funtion normally. The emergency stop switch checks out fine- even disconnected to be sure. As I said earlier, even changing the TCI doesn't solve the issue. All other electrical functions seem be fine. It also has a new gel battery. Charging system puts out 14+ volts when running. Hopefully you can see my frustration! Pretty soon I will shoot it and part it out!!! Not really - way to nice condition to do that!

I haven't been through the headlight/instrumnet wiring, as all that appears to work just fine. Could I be missing something there? At this point, I'm looking for a dead cat to swing over it to see if that helps. Never know!

Keith

[Poprock]

Lots of connectors in that headlight bucket. They all need to be cleaned. Also clean all your ground connections. When I did mine the headlight got at least 10% brighter. If you havent changed to spade fuses, do so. While you're in there, pull the tin that holds the fuse panel and clean the big connectors back there. Amazing stuff happens when everything is clean.

[Keithh]

Electrical problem update

Greets all,

Here is the latest installment of the possessed XS electrical problem for your reading pleasure!
After being on charge for a few days while I was out of town, I checked the battery voltage and it was just over 13 volts. When I cranked it over with meter checking voltage at the red/white wire at the TCI, the voltage dropped pretty fast to 10.1 or so - obviously not enough to stimulate the box. It seemed to be an abnormal drop. Checking voltage at the fuse box at the brown wire in, the voltage is at least .5 volts below battery voltage.

Looks like I'll go over the connections yet another time to see if we can improve on this. Is there anything else that I am missing that might pull down the voltage like that? Does the ballast resistor affect the box at all, or is it strictly for the coils?

Tomorrow I'll try the kick starter to see what happens.

Any more thoughts appreciated! I wonder if anyone converted back to breaker points! At least their easy to figure out!

Keith

[natemoen]

If you were measuring the voltage at the batter when you got those reading I would've your battery is trash.

Ballast resistor is just for the coils.

[GLoweVA]

Checking voltage at the fuse box at the brown wire in, the voltage is at least .5 volts below battery voltage

The Tan (Brown) wire going into the fuse block is kinda expected to drop a little.
That voltage has to come from the battery, thru the main fuse, thru the key switch then all the way back to the fuse block.

The Red/White wire that feeds the TCI has to go thru all that, continuing on from the fuse block (ignition fuse 10A) it goes up to the right handlebar (on/off) kill switch then comes back and splits off to feed the starter solenoid, the ballast resistor and the TCI.

So, If (without starting) you're getting good voltages up to this point, then your connections up to here should be okay.

Just a thought, (Maybe someone can chime in here) If the starter solenoid(coil) is drawing too much current, then the voltage drop at that point could cause the R/W wire voltage to be lower at the TCI.
Remember that his bike runs just fine, it's just a starting issue.

I think we've kinda figured out why you're not getting spark while starting, (low voltage at TCI), now we've just got to figure out why and why it only happens sometimes.

When I checked the battery, it was showing 12.7 volts. When cranking over, it dropped to 11.5 or so.

It sounds to me like the battery seems okay. It seems to be able to withstand the current draw from the starter.

Just to clearify something, there are 2 R/W wires to the TCI.
One diagram show one of these to be W/R, but then turns to R/W.
The first wire, (next to the black wire in the plug) is the power in.
This one is the one that needs the 10.5V to run.
The other wire (next to the Grey) is the one that feeds the coils to bypass the ballast resistor.
It gets it's voltage from the R/Y wire (from the starter solenoid) during starting (~12V) and when the bike is running it comes from the other R/W wire, this will only see ~9V due to the ballast resistor dropping some of the voltage.
Here's a pic of the circuit.

[tw1980]

I think we are assuming and speculating.1 when the bike doesn't start,does it have spark?If it has enough energy to crank the engine it has enough power to the TCI.Start looking for bad connections.Pick up wires broken?Both coils can not fail at the same time.Is there power to the coils?If so and you don't have spark I would suspect the pick up wires.

[GLoweVA]

It's not really speculating, he has no spark while starting and the problem only occurs sometimes.

Keith's been having this issue with his bike for months now.
This is his 3rd thread on the same problem.
When It does start, it runs fine. (perfect even)
He has checked his pick up wires and they are fine. So that's not the problem.
He's even swapped out with a new(er) harness and tried a different TCI.
He has enough juice to run the starter and crank the motor, but as you can read above, his voltage at the TCI drops to 10.1. (below the magic 10.5 that's needed for the TCI to work)

When I cranked it over with meter checking voltage at the red/white wire at the TCI, the voltage dropped pretty fast to 10.1 or so -

There's something that's causing the drop in voltage somewhere, but only during the starting. He thought it might have been the draw of the starter itself, but as stated, he's getting okay voltage during the start.

When I checked the battery, it was showing 12.7 volts. When cranking over, it dropped to 11.5 or so.

That's why I think it may be the starter solenoid(coil). It's in the circuit with the TCI box and may be causing the lower voltage at the TCI.
Maybe I can take the starter solenoid of my SG and drop it off at his house this weekend and he can swap them out and see if that cures his issue.

[crazy steve]

..Checking voltage at the fuse box at the brown wire in, the voltage is at least .5 volts below battery voltage...

That's too much drop IMO; you still have one or more marginal connections between the battery and the fuse panel. The higher the current in the circuit, the more critical it is that the connections be good. You need to check every connection (including the internal contacts of the ignition switch) and clean as neccessary to get that number lower. This is the main feed for the bike, and as all the systems current goes through this circuit, it needs to be near-perfect. I'm assuming that you're seeing this number with just the key 'on'; once you start the bike (and other circuits come on line), it will only get worse. Look here: http://www.xs11.com/forum/showthread.php?t=35339 for how to check individual connections/contacts. You really should be seeing zero resistance on these if they're good.

This can be tedious, finicky work, but there's no help for that. I spent several days chasing poor connections on my SG before I eliminated all the problems; in my case it was intermittently poor connections at the plugs between the handlebar controls and the main harness among others. My problem turned out to be mostly loose connections; the female half of the plugs wasn't gripping tight enough, by tightening those up for a better grip I got it fixed (that and liberal use of DeOxit...).

[GLoweVA]

I think I might have to agree with you Steve. He hasn't cleaned his key switch, so maybe that might be one of the (or the only) issue(s).

Loose connections could be a culprit too. That might explain the randomness of the fault. (when it does and doesn't happen)

I'd suggest that when he has a 'no spark' condition, then go thru and check continuity (resistance) of the circuits to see if there's one that's a little high and then find that connector.
Voltage checks might be good, but if the connection is just barely touching, then once current flows, the resistance felt thru the poor(loose) connection will cause a drop in voltage in the rest of the circuit.

[crazy steve]

As a retired electrician, I can tell you that intermittent type problems are the worst kind to troubleshoot. The only 'fix' is to go through the system very methodically and carefully, checking every connection until you find it.

Ideally, you should have no voltage drops in the circuits other than what you drop across the various components. But that will be impossible to achieve, so all you can do is reduce them to a minimum. Generally, the absolute maximum drop you can tolerate is 5% on a individual circuit, with a 3% figure 'overall' being considered 'acceptable' but not desired. On a 14 volt nominal system (bike running, charging system working properly), that means you shouldn't have more than a .4 volt drop in total for anything other than the starting circuit. If everything is right, you can get this, no problem.

[TopCatGr58]

If it has enough energy to crank the engine it has enough power to the TCI.

Hey Terry,

I have to disagree with this statement. I experienced this phenomenon myself with an aged battery. IT was able to crank the engine over, but did not have enough reserve capacity to provide the 10.5 volts to the TCI to get it to start. I put the jumper/booster battery JUST on the Ignition fuse circuit and the bike then started just fine with the otherwise weak battery. I replaced the faulty battery and have been able to start it just fine ever since.

T.C.