No spark at spark plugs - nothing acrosss the gap set at .040 and grounded to the motor.

S&S 96 cc inch evo withS&S carb
1. Difficulty starting at times
2.Sometimeswhile idling the bike will start to runon one spark plug
3.let the bike cool for a minute and restart it may go back to running ontwo plugs.
4. out riding today and it went to one plug - made it back home
5. bike will not start and there is no spark at either spark plug- front or rear.

What other test shouldI try or any suggestions ?????/


96 inch S&Sevo with super stock module ignition-single fire coilwith S&S carb & VOES

 

Check for bad connections in the wiring for the ignition circuit (from the battery all the way through to the spark plugs). Check your coil for continuity and impedence (ohms) on the primary and secondary sides. If it ain't either of those two, it's probably your module. If you have, or have access to, another known good coil of the same type, you could try that on the bike. Same thing with the module. Not too many people have spare modules laying around since they are quite expensive. Try everything else before blaming the module.
I had a coil fail intermittently and when it went away completely, it took the module with it (at least, they both had failed, I assume the coil killed the module). It can be very difficult to trouble shoot intermittent electrical problems.You will need a volt/ohm meter. There are inexpensive ones at Radio Shack or Harbor Freight.

 

How do you check a coil for continuity?.

Voltmeter - but what do you do to test
1. Primary wiringtest ??

2. Secondary wiringtest ??

 

What about the VOES??? Would that cause this?

 

zenon9,
I am assuming that the S&S super stock ignition is a single fire type with a 3 ohm coil. The coil should have three primary wire terminals. Mark the wires for which terminal they are connected to and remove the wiring from the coil. Using an ohmmeter that can read single digit resistance, place one lead on the "common" primary terminal. This terminal should have the switched 12 volt power from the ignition switch via the run/stop switch on your handlebars or maybe one of those ignition relays that bypasses all that wiring up at the handlebars. There may be another wire on it that goes to the ignition module for its 12 volt power supply.
The other two primary wire terminals are for the individual cylinders coil primary windings and they should have one wire each going to the ignition module. Place the other meter lead on one of those terminals so you are taking a reading across the "common" to one of the other primary terminals. It should read 3 ohms give or take a couple of tenths of an ohm (assuming it is 3 ohm coil). Check the other primary winding by leaving the one lead on the "common" and switch the other lead to the other primary terminal. You should get about the same reading for both primary windings.
To check the secondary windings, leave the one lead on the "common" primary winding and insert the other lead into one of the spark plug wire towers. You should get a reading in thousands of ohms on this test (lots of windings on the secondary side). Move the lead from the one tower to the other tower. You should get about the same reading.
If you can't get the meters lead to reach into the spark plug wire tower, get a jumper wire with alligator clips on each end and a small screwdriver. Using the jumper wire clipped between the meter lead and the screwdriver, use the screwdriver to reach the connection down in the tower. While you're in there poking around, check the connections down in the tower for corrosion and clean them as necessary.
If you get balanced readings on the primary and secondary sides of the coil, it is probably okay. This isn't a guarantee that the coil is good because my bad coil had intermittent good connections...remember what I said about how hard it is to troubleshoot intermittent electrical problems.
Whilst you have the meter out and you are checking stuff, check your spark plug wires for continuity/resistance. Wiggle them around as you check 'em to make sure they are not opening up in certain positions. If they read about the same resistance, they are probably okay and your problem is either wiring in the ignition circuit, a bad module (I hope not), or possibly bad spark plugs. Run (as in physically check) the wires from the module all the way to where they connect to the other parts of the ignition to make sure they are not shorting to ground somewhere. The smallest pinch or place where it can vibrate can cut or wear through wire insulation and cause a wire to short to ground. This includes the tachometer trigger wire from the module.
This brings us to the VOES and Neil Ivanovich's question. I don't see where a shorted wire to the VOES or a bad VOES could cause the ignition to fail. It could cause the ignition system to switch between the advanced and the retarded ignition curves if it was shorting to ground and that would affect performance but I just don't see it killing the ignition.
Good luck man.

 

zenon9,
It would probably be a good idea to check your coil cold first and if it checks okay, check it again after heating it with a hair dryer.

 

OK, Thanks everyone I will be running these test today - Thursday

Willgetbackwith you tonightwith the results.

 

Hi Guys

Wellthe Bad news is I have not ideas was wrong with this bike.

That leads me to the Good news - whichis - The bike is firing on every hit at the moment.

OK-as the story goes - I removed the gas tank and removed the coil from the get go- no messing around with those tight spots unless it's a female.

took coil completely offf bike to run coil test- primaryto negfront= 3.1 ohm and same with rear

In testing secondary-I waslost at ohms setting 20k = 9.1and at ohms setting 200k= 9.1 at 2000k = 009 so I have no idea what that was all about in testing each plug tower.

Next I check my starter booster relay - switch on and all that stuff= OK 12.93 volts at postive terminal and negative terminal- so that wasn,t it.

At this point I ran the wires- so I clippedalmost every wire tie that was routing the nose cone sensor wires to the coil. I saw 2 ( two) spot thatconcerned me so I placed electrical tape over one and left the second wiring locationfree of frame contact. Performed a spark plug test and was amazed the both cylinders were firing. So next I jimmierigid my gas feed with tubing andabout 16 oz of gas - hit the switch and there you go - fire inhog , fire in hog

I will put it back topgether later but I stillDO NOT KNOW the real issue.

OK-one other observation - Ihave just replaced the stator - my fault on this one - did not lock down the compensator nut tight enough - so the rotor got wracked -rplaced the rotor but did not usedproper spacing disc (should have put it back the same way I found it - OK , my Bad ).
So I fixed my Bad- here is the rub - when the stator was grounded - the tachgauge would jump around like crazy - fixed the stator and the tach gauzewas better but alittle erratic still - now after going through this last no spark fix - the tachgauze is back to normal.

So - I amassuming the problem was a GROUNDEDWIRE to FRAME - and I think it was the tach wire making contact beneath the gas tank R/Tvibration - but I have no real evidence.

Stay tuned - I will let youknow after I re-assemble and run the bike course.

Thanks Guys - and Yes I had a few today - I mean after ALL - this Harley thing

Sometimesmakes you want to Cuss.

Megawatt - run that secondary coil testing by me again or can I get 40,000 ohms reading on a digital voltmeter.

I would like to know for future reference.

Thanks again - Joka

 

Your secondary side reading of 9100 ohms is the same as the reading I got on a known good coil I have so I'd say you're golden on the coil as long as it is consistant. Did you try the coil test again after heating it with a hair dryer?

 

No - I just stopped after the bike fired up
I get your point - but at this timeI have a strong feeling it wasa ground fault from an exposed wire beneath the gas tank.

I will let you know if I run into any problem with spark at the plugs again.


Thanks