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1993 R100 no spark

milo

Member
Total electrical novice with an electrical problem. 1993 R100 started then suddenly quit. Toggled kill switch but nothing. Then checked and no spark to either plug. Pulled the tank and disconnected and reconnected every connector, all are tight and clean. Wesco battery shows 12.7 v but is 12 years old so I replaced it. Toggled kill switch with plugs out but connected to wires and grounded on engine, no spark. Replace bean can and module with new Wedgetail system, no spark. Ohm between the (black) coil's 2 terminals reads 1.0 with multi meter set to 200. Replace spark plug and wires. Tom sent a new module but it does the same as the first Wedgetail: S mark aligned, power on, slowly rotate can counter clockwise but neither light illuminates. Repeat a couple times finally the trigger light lights, stop rotating but then it immediately goes out. Repeat this time no lights at all again. I inserted the meter prongs into both spare plug caps, the meter showed 1 . regardless of meter setting. Then finally 24.8 with the meter set at 200K. What should I be trying next?
 
Wow, sounds like you've done a lot! It's always frustrating when things suddenly quit. So the bike started and while running, it quits. First off, the bike needs a functioning battery to run...it's a battery-coil ignition. You replaced the battery but still won't start. I'd be curious to see what the voltage is across the battery as you hit the starter button.

I'm not as familiar the later bikes coils...is there only one coil? I guess then it has two towers that the spark plug wires insert into? You said you inserted probes in the spark plug caps and you got a reading of "1" and then later a reading of "24.8". Those numbers don't seem right at all. What's the scale?? Each stock spark plug cap has a built in 5000 ohm resistor. So measuring from one cap to the end of that plug wire should be around 5000. Seems like we should start with trying to figure some of the basic wiring.
 
You can utilize your multimeter to determine where the break is occurring - you’ve checked the battery, but you can also check the coils. Also use the continuity feature to make sure your wiring is solid along with your grounds. Since the bike started, my hunch is that something either shorted, you blew a fuse, or a connector came apart.
 
Wedgetail Ignition module with it's own "bean can"! Did you talk with Tom to verify your installation or sending you another module/bean can?

Btw, did the OEM ignition module and bean can work before you installed the Wedgetail?
 
I installed a Wedgetail system about a year ago and I think the built-in static timing is junk. I could not get it to work consistently. Get a timing light and adjust the timing that way.
 
Yes battery was fine and the new one is too, lights are bright and the starter spins the motor fast. Voltage on both batteries were right at 100% a day or longer after the Tender was disconnected. I'll look at voltage as the starter is turning but honestly I don't believe it's the battery because it started right up and was idling fast on part choke when it suddenly just stopped. And no spark since.

I must not have the meter set right because it's showing nothing through either spark plug wire just by themselves, original set or the new set I just put on. Scale at 200 it shows 1, with a meter prong on each coil spade (with wires removed from the spade). Rick from Motoelektrik said it should be .75.

I don't know for sure if the OEM module and bean can worked or not, but there was no spark with them.
 
I am not sure but the 93 bike may have an issue with the coil cracking? That would be visible on the coil.
You need to get your wiring schematic and check power supply to the ignition module, is there 12 volts. Check with snowbum's website on coil checking.

Tom, you mean Tom Cutter? a good guy. I would contact him again and find out what the procedure is for troubleshooting the Wedgetail system.
Snowbum may also have a write up on how to troubleshoot the ignition module.

Now for the simple check, LOL, Take the front engine cover off and make sure you didn't pinch the wires leading from the Hall effect module. Check the plug.

I don't have a wiring schematic for your bike so I can't give you any locations to check for voltage in the system. Good luck, St.
 
I am not sure but the 93 bike may have an issue with the coil cracking? That would be visible on the coil.
You need to get your wiring schematic and check power supply to the ignition module, is there 12 volts. Check with snowbum's website on coil checking.

Tom, you mean Tom Cutter? a good guy. I would contact him again and find out what the procedure is for troubleshooting the Wedgetail system.
Snowbum may also have a write up on how to troubleshoot the ignition module.

Now for the simple check, LOL, Take the front engine cover off and make sure you didn't pinch the wires leading from the Hall effect module. Check the plug.

I don't have a wiring schematic for your bike so I can't give you any locations to check for voltage in the system. Good luck, St.
Thanks. I'll look closely at the coil for cracking. The module must have power to it because the lights have come on, although not as they are supposed to. Does the module receive constant power?

Tom just forwarded new timing instructions which I'll try.

Front engine cover hasn't been put back, it is still off.
 
I had a '93 R100RT. If memory serves, the bike has one dual output coil. The coil cracking issue was resolved by then, but was an issue with two 1988 RT's two of my buddies had. And that problem only showed itself in wet weather. Remember that a coil is essentially a transformer, stepping up the 12vdc source to enough voltage (several thousand) to jump the spark plug terminals. With key on, what's the voltage (DC volts) at the primary terminals? It should be 12 volts. Then with key off, measure resistance (ohms) at the same primary terminals. Then remove both spark plug leads and measure the resistance across those (secondary side).
 
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