No spark, what went wrong?

[nikonyamaha]

Long time follower of the forum but registered last week. Here is my dilemma:
Carbs were cleaned and sync'd. Original coils were arcing from the wires to the engine so were replaced with "new old stock" along with new NGK spark plug caps. Orange, grey, & red/white wires from the coil properly terminated. Adjusted the idle and did a test run in the neighborhood and all was well. Started in the morning, idled good and pulled strong with no lag or hesitation. But would not start in the afternoon. No spark to the spark plugs. I am not good at tracing electrical problems (if that's what it is), so what do I look for? Is it the resistor (which was not changed out); is it a possible short at the kill switch, is it the" new" coils themselves? All help is appreciated.

[natemoen]

What year and model bike do you have? Does your bike have a ballast resistor on it? Have you tested the resistance of the coils? Did any of the wire come apart? Do you still have power reaching the coils?

[bikerphil]

If you have the old type glass fuse box, might have a problem there. If your battery is weak, it won't give enough juice to the TCI to fire the coils.

[nikonyamaha]

1980 XS1100G; yes, original ballast resistor; no have not yet checked the resistance; no wires came apart.

[natemoen]

Does the starter turn the engine over or when you try to start it does it do nothing?

[nikonyamaha]

The starter turns the motor over with enough rpms.

[natemoen]

Do you have a multimeter available to use? If so check the voltage across the battery terminals. Do you still have the glass fuses in the fuse block? If so take each fuse out check it with the multimeter (if available) and when you have the fuse out twist the metal ends. If they break they were bad and needed to be replaced anyways, if not you might be ok. (on another note if you have the glass fuses ASAP switch over to a blade style fuse block a mod here names TopCatGr sells them cheap and its a easy swap out)

[nikonyamaha]

All glass fuses have been replaced with the blade style. I will check the fuses tomorrow.

[natemoen]

Typically if the kill switch or tipover switch is not working right (or activated) then the starter does not even spin so I doubt it is that. I would say to check the fuses first. Then if you do have a multimeter (if not you can get one cheap usually for under 20 bucks) check the ohms on the coils if you put the meter leads on the 2 small wires coming from the coil you should get about 1.5 ohms. If you put the meter leads on the spark plug wires (without the plug caps) you should get about 15,000 ohms. You can leave the plug caps on when you do this test but then you have to add on to the reading for the resistance that you plug caps have built in (its usually 5,000 ohms per cap so 10,000 ohms total to add on). If either of those numbers are off by more than about +/- 10% the coils are bad. You can check the ohms at the ballast resister as well you could read about 1.5 ohms here as well. Check voltage at the ballast resistor while your there and you should get 12 volts coming into the resistor and I believe 9 volts coming out of the resistor. I am not sure what the voltage should be at the coils so I will not say what that would be but do some research here and I am sure you can find it.

Also check the voltage at the battery and make sure it does not ever drop bellow 10.5 v (even when cranking) if it does then the TCI does not send spark to the coils.

Keep us posted

[b.walker5]

I am not sure what the voltage should be at the coils so I will not say what that would be but do some research here and I am sure you can find it.

9 volts at the coils while at rest or with the motor running. 12 volts (battery voltage) while cranking. Theres a circuit in the TCI which bypasses the resistor for starting.

As stated, Resistor should show 12 volts on one side (battery voltage) and 9 volts on the other while under load. i.e. coils connected. Bypassing the resistor by bridging the wires together will rule it out of the equation and supply full power to the coils. Many are running happily this way, but there is a school of thought that suggests that the TCI could be damaged by doing so. I dont subscribe to that school but either way it's not going to do any harm for a short test.

Also as stated, check your battery voltage, but while cranking, if the battery voltage to the TCI drops below 10.5 it wont fire the coils.

[tantor]

Also check the voltage at the battery and make sure it does not ever drop bellow 10.5 v (even when cranking) if it does then the TCI does not send spark to the coils.

This was one fact that I needed to know. Thanks for posting this!

[fredintoon]

- - - Started in the morning, idled good and pulled strong with no lag or hesitation. But would not start in the afternoon. - - -

Hi Nikon,
same thing happened to my XS11SG. Running normally when we got to the hotel in the evening. At the start of the rally next morning, switch on, everything lights up, push the button, nada. Did that day's ride in the Buick. Fuses looked OK so it has to be the effin' killswitch, right? Did the most thorough killswitch cleaning job ever done in front of an audience in a hotel car park. Still nada. Checked every fuse with a multimeter. Replaced the blown fuse. Vroom!
Note that a blade-style mini-fuse can blow and still look OK from the outside, just like a glass-tube one.

[nikonyamaha]

Here are the stats:
Battery: 12.6v at rest, 11.8v at start up, 13.0v at 2000rpm, 14.0-15.0v at 3000+ rpms. So this should rule out the rectifier.

Ballast resistor: 1.79 ohms, 11v in & out at rest. (I forgot to check the ballast resistor voltage during start up and running. Could this be faulty?)

Pick-up coils: 759 ohms & 701 ohms. Per manual, in spec.

Ignition coils: primary wire orange - 24.6 ohms; primary wire gray - 24.32 ohms. Secondary wires 1/4 - 24,620 ohms; secondary wires 2/3 - 24,320 ohms

10 amp ignition fuse OK (if it was blown, the engine would not turn). For the same reason I ruled out the kill and tip-over switch because the starter spins.

Coil resistance is high and yet the bike will start. But after running for an hour and sitting in the sun at 90+ degrees for 10 hrs it will not starting (sometimes). Does ambient temperature having anything to do with it? But once it starts and the motor is at temperature it will restart with no problem. And it never misses while riding.

I am at a loss, did I miss anything?. The manual stated that if the pick-up & ignition coils were OK then the ignitor unit (the black box) is faulty. An expensive part to replace. Is new old stock still considered good?

[natemoen]

If your primary coils are reading that high then the coils are most likely bad. They should not be reading anything over about 2 ohm!

Also when you checked the pickup coil wires did you move or pull on the wires underneath the timing cover? If not the wires could probably be bad (its a common problem with these bikes). Here is a link to the tip on how to check them and fix them if it is a problem http://www.xs11.com/forum/showthread.php?t=543 .

With the secondary wires I am assuming that you checked the coils with 5K resistor plug caps on? Just want to make sure because if the caps were not on then that side would be bad as well.

I doubt its going to be the TCI but its not unheard of.

[b.walker5]

Hi NikonYamaha.

Hard starting when hot isnt all that uncommon, but there can be lots of reasons for it. Mine was fuel related, but the symptons were slightly different to yours.

Theres a couple of threads here that have dealt with the subject in the past so maybe you can pick up some extra clues and hints from them.. do a search for more and be perpared to read a lot.

http://www.xs11.com/forum/showthread...d+starting+hot

http://www.xs11.com/forum/showthread...d+starting+hot

Recheck that primary coil reading, and the method of testing. Thats very high. As Nate said, shouldnt be any higher than 2.0 ohms. Book says 1.5 +/- 10% @ 20 degrees. Secondaries also look a little high, should be 15k +/- 10%.

Hope this helps
Brian