no start, Confused and frustrated

[Sgriger534]

I can not get any spark from my bike, it turns over like a champ, but no fire. I have twelve volts at the coils, i am confused why i am not getting anything from the plugs

[CatatonicBug]

Have you tried removing the plug boots and trimming 1/4" off the ends of the wires, then re-installing the boots? It might be just that simple. JAT

[Sgriger534]

it was running fine till just a few days ago, all i did was clean the wiring up at the tailights and not i can't get anything at all from the plugs

[dbeardslee]

I'd do as Bug suggested, but you might also put a digital multimeter on your high tension wires and check the resistance. Just put a probe in the end of each high tension wire for a given coil (with the caps removed), set you multimeter to the 20000 ohm setting, and take a reading. Spec is 15000 ohms plus or minus 10%. If your coils are out of spec you might consider grafting in new wires, or replacing the coils. The other thing to check is your pickup coil wires. You can check them at the TCI by pulling the 4-wire connector, holding it with the 'slots' horizontal and putting a probe on each of the upper connectors. Set your dmm to the 2000 ohm range and take a reading. Should be 720 ohms plus or minus 20%. Repeat test for the lower 'slots'. Finish the test by removing the timing cover and gently pulling on the wires gently between your fingers. If you see the wire sheath obviously stretch you'll know it's time to redo your pickup wires.

[CatatonicBug]

Edit: Yeah, what he said

If you messed with the wiring, you may have dislodged a wire in one of the connectors that sends juice to the coils.

[psycoreefer]

I'll start posting here, instead of your taillight thread....just to keep it all together.

In the other thread you mentioned you only have 10.5 volts at the TCI, with ignition on. Have you addressed that? I really don't think the TCI will work correctly with that low voltage. If your reading 12 at the coils and only 10.5 at the TCI then you've got some connectors that need cleaning.

[BigRed]

I had this problem (low voltage at TCI was preventing the bike from starting). For me, it was bad connections; especially the ground connections at the voltage regulator. Unbolt your regulator, and file where it touches the frame, and file the ground wires that are bolted there as well. I hope this is your problem, because it's really easy to fix.

You should also unplug and clean all your electrical connectors because they will almost definately cause you problems.

Have you checked the voltage while you're cranking? It can drop sharply to low enough that you don't get a spark... I'm pretty sure you need about 10.5 volts for the TCI to work.

Good luck!

[randy]

Edit: Yeah, what he said

If you messed with the wiring, you may have dislodged a wire in one of the connectors that sends juice to the coils.

Ditto. The harnesses for the tail and the TCI are in close proximity, so double-check them.

BTW, it would help a lot if you add your model description to your signature. Some troubles and solutions are model-specific.

[Sgriger534]

it is a 78 xs11. What happens if the tci gets fried. When i was messing with the taillights i think i might have put power to the ground, non of the fuses are bad but i fear that maybe i messed the tci up.I don't know if this is werid but I have six volts at the end of the plug wire with the key on and it goes down when i crank, i don't know if that is werid to have power there or not, i am use to distriburted engines.

[mxmikie]

it is a 78 xs11. What happens if the tci gets fried. When i was messing with the taillights i think i might have put power to the ground, non of the fuses are bad but i fear that maybe i messed the tci up.I don't know if this is werid but I have six volts at the end of the plug wire with the key on and it goes down when i crank, i don't know if that is werid to have power there or not, i am use to distriburted engines.

i have tci's

[randy]

it is a 78 xs11. What happens if the tci gets fried. When i was messing with the taillights i think i might have put power to the ground, non of the fuses are bad but i fear that maybe i messed the tci up.I don't know if this is werid but I have six volts at the end of the plug wire with the key on and it goes down when i crank, i don't know if that is werid to have power there or not, i am use to distriburted engines.

Putting + to ground only would have (SHOULD HAVE) blown a fuse. Are you saying that you have 6 volts at the SPARK PLUG wire? If so, that's a new one.

[Sgriger534]

yeah, with the key and without cranking i have six volts at the plug wire, and when you crank of course it drops to about three volts, i am not sure how these ignition systems work, but i didn't think this was right

[dbeardslee]

Here's some tests you can run to try and nail it down. I didn't want to retype all this stuff again, so I copied and pasted from other posts, so if it get's a little redundant, that's why .

On the starter solenoid, just under and a little to the right of the 'hot' wire (bolted on wire - goes to battery +) there should be a red/wht terminating in a little blob of solder. Those are the points you jumper with a wire to bypass the red/wht in the ignition. If it starts when you hit the starter with the jumper in place, and dies when you remove it, you'll know your problem is somewhere in the red/wht.

If you want to run some continuity tests on the red/wht, open the handlebar switch. One of the red/wht wires leads to the fuse block, and the other goes through the ballast resistor connector and then to the 'Y' connector at the coils. Unplug the ballast connectors, and test the wire from the 'Y' to the connector, and then from the other ballast connector to the handlebar switch. If all wires show continuity, plug the ballast connectors back together and test from the handlebar switch to the 'y' connector. If the continuity readings change you'll know the connectors are the problem. I'm guessing that's what it's going to show as that's where the heat is. When I removed my ballast resistor, I cut the connectors off and soldered the ends together and put a heat shrink over the connection. Nothing to corrode or short - no more problems out of that puppy.

If you want to check your starter button, you can do it with out taking the switch off. If you unplug the connector down by the gas tank, and put one probe from a multimeter on the blue/wht wire, and hold the other probe to the switch housing with the mm set to continuity, you should see an open circuit that closes when you push the button. If it shows continuity all the time, or doesn't show continuity when you push the button, then the button isn't doing its thing.

Sounds like you're making good progress. Have you checked your pickup coil wires yet? If you haven't here's how - take a digital multimeter, pull the four wire connector at the TCI, and hold it so the 'slots' are horizontal. Put a probe in each one of the 'upper slots' and take a reading. Should be 720 ohms plus or minus 20%. Repeat on the 'lower slots'. If the numbers are within spec, replace the four wire connector, and turn the ignition on but not running (if they're not in spec, jump to the last paragraph). From the back of the large TCI connector put a probe on the red/wht, orange, grey, and wht/red (one at a time) and put the other probe on a good ground. Set your dmm to volts and take a reading. Should be 12v. Repeat on the black/wht and you should get a reading of 6v. If your voltages are significantly less (I would say less that 11.5v), get to work cleaning all connectors, and pay particular attention to the red/wht wire. Don't forget to clean the handlebar switch too - and be careful with the kill switch. When you get the switch apart, there's a screw that holds the kill switch in. Once you've removed it you'll see a little circlip on a brass post. Watch it when you remove the circlip and pull the assembly apart - there's a small ball bearing and some springs and stuff in there that can really fly if you're not careful.

And to finish the pickup coil wire test, remove the timing cover (left side of motor) and take each pickup coil wire in your fingers and pull gently. If you've got any breaks inside the wires you'll see the wire sheath stretch. Just pull gently - the sheath will slide around on the wire a bit, and if you pull too hard you can almost make a good wire look bad. While you're in there you might check your pickup coil gap too.

[BigRed]

I'm pretty sure that has to mean that your coils are cooked, and you're shorting between the primary and secondary windings. Can't think of anything else that would be causing you to have voltage at the end of your spark plug wire without the bike running or cranking.

By the way, you might be lucky that your coils are fried... you don't want to be looking for voltage at the end of your spark plug wire when you're cranking the engine... that's a really good way to fry yourself with something like 75,000V depending on what coils you have.

[Ivan]

To check for shorted coils, check for continuity (ohms) between the small wires on the coils and the plug wires. You should have infinity meaning that your meter should say 1. or OL or Err.

Also, the voltage on the plug wire could be a symptom of the TCI going nuts and letting a small amount of rapidly switching voltage to the coil, which is amplified by the transformer (coil) and averaged out by the circuitry in the multi meterdisplay not being able to keep up. Check the same plug wire on the AC volts setting. If you get AC volts, chances are your coils are fine and your TCI has freaked.

I learned this one on a GM car once. There was voltage on the plug wires, and I couldn't figure out where it was coming from. So I put my spark tester in and cranked it to see if it would spark. It didn't until the engine stopped moving, then there was a very bright constant spark that made a whistle sound about as loud as a car horn for about 15 seconds until the ignition module popped and let out the magic smoke. My boss came over from the whistleing noise and we both stood there with a dubmfounded look on our faces that read "WTF!?!?" It was good for a laugh.