Tri-Spark EI and coil testing

jamesp

jamesp

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My Norton has developed spitting and back firing at low throttle openings. Seems to run ok when throttle is stabbed to higher RPM. I replaced the original Amals with new Premiers, made no difference. I have checked the timing, grounds, connections, and voltages, all seem to be good. The bike is newly wired with CNW harness, negative ground, three phase alternator and .Tri-Spark regulator. I wired the .EI accordingly per TS instructions. The .EI unit and Tri-Spark coils are about ten years old. It seemed to be running fine when first brought back to life, but developed the spitting and back firing. I do not use chokes, but have to shut it off before it gets fully warmed.

I believe either the .EI unit or one of the coils may be at fault. The red timing light comes on for static timing, but the test function does not work. I am looking for any suggestions on how to test the EI unit and the coils using a multi meter. Thank you in advance.
 
I guess you have tried new plugs? Maybe worth running a cable direct from the battery to the E.I. To rule out anything like the ignition or kill switches.
 
jamesp said:
My Norton has developed spitting and back firing at low throttle openings. Seems to run ok when throttle is stabbed to higher RPM. I replaced the original Amals with new Premiers, made no difference. I have checked the timing, grounds, connections, and voltages, all seem to be good. The bike is newly wired with CNW harness, negative ground, three phase alternator and .Tri-Spark regulator. I wired the .EI accordingly per TS instructions. The .EI unit and Tri-Spark coils are about ten years old. It seemed to be running fine when first brought back to life, but developed the spitting and back firing. I do not use chokes, but have to shut it off before it gets fully warmed.

I believe either the .EI unit or one of the coils may be at fault. The red timing light comes on for static timing, but the test function does not work. I am looking for any suggestions on how to test the EI unit and the coils using a multi meter. Thank you in advance.
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Testing the coils is simple. Disconnect the Black/White wire that goes from the Tri-Spark to the - of one of the coils. With the ignition on, use a jumper between the cylinder head and the coil you just removed the wire from. Each time you disconnect the jumper, both plugs should fire.

A far as the Tri-Spark self-test not working, most likely the button has gone bad or you are not actually pushing it and of course, the button must be pushed and held before turning on the ignition.

Did you do the tests I gave you in my email? Have you done the strobe timing? Have you sync'ed the carbs?
 
If you put in new carbs and it made no difference , it's electrical .
Trace backwards from the battery . Use a jumper wire from the battery straight to the ignition , as suggested . Run it . If the issue persists , it's in this direct circuit . This narrows things down to say your ignition , coils , HT leads being suspect .
Eliminate the kill switch by soldering the 2 wires together , at the switch . Clean up fuse holder . Clean up battery connections . Check or replace battery itself . Good luck . Enjoy .
 
jamesp said:
My Norton has developed spitting and back firing at low throttle openings. Seems to run ok when throttle is stabbed to higher RPM. I replaced the original Amals with new Premiers, made no difference. I have checked the timing, grounds, connections, and voltages, all seem to be good. The bike is newly wired with CNW harness, negative ground, three phase alternator and .Tri-Spark regulator. I wired the .EI accordingly per TS instructions. The .EI unit and Tri-Spark coils are about ten years old. It seemed to be running fine when first brought back to life, but developed the spitting and back firing. I do not use chokes, but have to shut it off before it gets fully warmed.

I believe either the .EI unit or one of the coils may be at fault. The red timing light comes on for static timing, but the test function does not work. I am looking for any suggestions on how to test the EI unit and the coils using a multi meter. Thank you in advance.
Click to expand...
Mine was doing the same,it was the ignition switch. Striped and cleaned up, problem gone.
 
marshg246 said:
Testing the coils is simple. Disconnect the Black/White wire that goes from the Tri-Spark to the - of one of the coils. With the ignition on, use a jumper between the cylinder head and the coil you just removed the wire from. Each time you disconnect the jumper, both plugs should fire.

A far as the Tri-Spark self-test not working, most likely the button has gone bad or you are not actually pushing it and of course, the button must be pushed and held before turning on the ignition.

Did you do the tests I gave you in my email? Have you done the strobe timing? Have you sync'ed the carbs?
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Hi Greg, yes, I checked the voltages and grounds and found the voltages were the same as the battery at each junction.
 
Thank you for all the responses. I will give them a try as soon as I can get back to it.
 
marshg246 said:
Testing the coils is simple. Disconnect the Black/White wire that goes from the Tri-Spark to the - of one of the coils. With the ignition on, use a jumper between the cylinder head and the coil you just removed the wire from. Each time you disconnect the jumper, both plugs should fire.
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Will this test rule out an intermittent short in the coil windings?
 
jamesp said:
Will this test rule out an intermittent short in the coil windings?
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No, but since the bike runs fine at higher RPMs, you do not have an intermittent short or open in the coils. You do not have an intermittent problem at all since it always has a problem at low RPMs and never has a problem at higher RPMs. As I've said before, it's unlikely to be an electrical problem for the same reason.

AFAIK, you've still not strobe timed the bike. If the timing is correct, just because you installed new carbs does not mean that the carbs are properly synced and the air screws properly adjusted.
 
marshg246 said:
No, but since the bike runs fine at higher RPMs, you do not have an intermittent short or open in the coils. You do not have an intermittent problem at all since it always has a problem at low RPMs and never has a problem at higher RPMs. As I've said before, it's unlikely to be an electrical problem for the same reason.

AFAIK, you've still not strobe timed the bike. If the timing is correct, just because you installed new carbs does not mean that the carbs are properly synced and the air screws properly adjusted.
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What you say about the intermittent problem not being intermittent makes sense. The carbs are synced as I am using a gantry and I checked it. The old carbs were also on the same gantry. The gantry is a thing of beauty when working well. It was running and idling well before the back firing started. The back firing started before I was able to put a light on it. Under current conditions, I cannot run it very long. Stephen Kelly of Tri-Spark thinks the EI stator could be at fault since the test function is not working. He has offered to test it. Thank you for your input, I appreciate it. I really do dislike electrical problems.
 
Have you tested for air leaks, the cross over balance tube on manifolds and the carb to mani to head joints? We had a recent thread on por running HiRider and after much work and checking, it turned out to be a crack in the balance tube.
 
Tornado said:
Have you tested for air leaks, the cross over balance tube on manifolds and the carb to mani to head joints? We had a recent thread on por running HiRider and after much work and checking, it turned out to be a crack in the balance tube.
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No, I haven’t done that. The carbs, o-rings between carb and manifold, and insulators are all new. The Amal literature for the new Premiers stated that they had been tested before shipping. My old carbs had clear pilot jets. Both sets of carbs acted the same, so the testing you mentioned did not cross my mind. As I am running out of things to try, I will keep your suggestions in mind. Thanks.
 
jamesp said:
No, I haven’t done that. The carbs, o-rings between carb and manifold, and insulators are all new. The Amal literature for the new Premiers stated that they had been tested before shipping. My old carbs had clear pilot jets. Both sets of carbs acted the same, so the testing you mentioned did not cross my mind. As I am running out of things to try, I will keep your suggestions in mind. Thanks.
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I assume you’re aware of the potentially too small premier pilot jet topic?

Do yours have #17s or #19s fitted ?
 
Quite a few people have reported swarf with new Premiers over the last few years, even though maker says otherwise. Timing can still be checked again….
 
jamesp said:
No, I haven’t done that. The carbs, o-rings between carb and manifold, and insulators are all new. The Amal literature for the new Premiers stated that they had been tested before shipping. My old carbs had clear pilot jets. Both sets of carbs acted the same, so the testing you mentioned did not cross my mind. As I am running out of things to try, I will keep your suggestions in mind. Thanks.
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Sound like it's running too lean mixture at low rpms.
Try it with the pilot jet screws adjusted to only 1/2 a turn out.
Are you sure your new Premiers are fitted with the correct pilot jets?

I'm asking this because I had a similar problem and it turned out to be carb issues.
Running with a little choke would temporarily cure the low rpm problems for me and helped me diagnose the problem, but apparently you don't have chokes fitted so can't try that.
 
jamesp said:
No, I haven’t done that. The carbs, o-rings between carb and manifold, and insulators are all new. The Amal literature for the new Premiers stated that they had been tested before shipping. My old carbs had clear pilot jets. Both sets of carbs acted the same, so the testing you mentioned did not cross my mind. As I am running out of things to try, I will keep your suggestions in mind. Thanks.
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Always best to confirm your assumptions when trying to solve bike issues, at least in my experience.

Even perfect carbs can succumb to dirt accumulating in the pilot jets from the tank after some time running fine.
 
Skoti said:
Sound like it's running too lean mixture at low rpms.
Try it with the pilot jet screws adjusted to only 1/2 a turn out.
Are you sure your new Premiers are fitted with the correct pilot jets?

I'm asking this because I had a similar problem and it turned out to be carb issues.
Running with a little choke would temporarily cure the low rpm problems for me and helped me diagnose the problem, but apparently you don't have chokes fitted so can't try that.
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I bought the carbs from Greg Marsh, so I feel confident he would size them correctly. Also, the motor performed the same way with my old carbs, no difference.
 
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