Triumph Stag changed coil now won't start

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Peter-109
Posts: 38
Joined: Tue Feb 15, 2011 7:06 pm

Triumph Stag changed coil now won't start

#1 Post by Peter-109 »

Hello everyone,
Just drove the Stag over to Robsport, drove home and changed the ignition coil and now I won't start, won't fire at all. I haven't checked for a spark as it got dark, but does the coil body need an earth? Being as the coil is painted black I wasn't sure.
Cheers!
-Peter
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JPB
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Joined: Fri Jan 07, 2011 3:24 pm

Re: Triumph Stag changed coil now won't start

#2 Post by JPB »

No, the coil body doesn't need to be earthed.
J
"Home is where you park it", so the saying goes. That may yet come true.. :oops:
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Luxobarge
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Location: Horne, Surreyshire

Re: Triumph Stag changed coil now won't start

#3 Post by Luxobarge »

JPB wrote:No, the coil body doesn't need to be earthed.
Err - far be it from me to question someone who clearly knows more about electronics than me, but surely it does? How does the HT side complete a circuit? Surely ones side of the secondary coil is the HT king lead, and the other side is the coil body = earth?

OP - do you have the original coil still? I know I'd be changing that back straight away to check it really is a fault isolated to the coil.

Cheers! :D
Some people are like Slinkies - they serve no useful purpose, but they still bring a smile to your face when you push them downstairs.
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JPB
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Re: Triumph Stag changed coil now won't start

#4 Post by JPB »

The "earth" side of both coils is common. ;)
The following sketch should explain why no can earthing is needed:

Image
J
"Home is where you park it", so the saying goes. That may yet come true.. :oops:
Peter-109
Posts: 38
Joined: Tue Feb 15, 2011 7:06 pm

Re: Triumph Stag changed coil now won't start

#5 Post by Peter-109 »

Tried the old coil this morning and nothing, sooo i must have touched or knocked something but no idea what it is :S
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Luxobarge
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Re: Triumph Stag changed coil now won't start

#6 Post by Luxobarge »

Thanks John. Never knew that!

Peter - correct, you've somehow introduced the fault when you changed the coil. So, I assume this is still conventional points ignition? In that case, first check all the coil and dizzy connections for soundness. Then go round with a meter and see what's missing. Check the Low Tension side - you have 12V at the + terminal of the coil? If not, trace this back until you do. Then check you have a voltage on the other side of the coil with the points open, and then 0V with them closed - or you could check this side with an ohm-meter for continuity.

A wiring diagram will help here if you're not sure what goes where.

All the best with it! :D
Some people are like Slinkies - they serve no useful purpose, but they still bring a smile to your face when you push them downstairs.
Peter-109
Posts: 38
Joined: Tue Feb 15, 2011 7:06 pm

Re: Triumph Stag changed coil now won't start

#7 Post by Peter-109 »

Ah right forgot to mention it is on lumenition. Yep I have 12v to the + side then the -VE side i have 12v aswell and that has the wire to the lumenition box and 2 other orange wires. is that right? I have 12 volts on the - side when the little disc isn't breaking the signal in the dizzy so is that wrong? Cheers!
Wicksy
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Joined: Fri Feb 18, 2011 5:32 pm
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Re: Triumph Stag changed coil now won't start

#8 Post by Wicksy »

It's gone quiet :shock: Assuming you still have the problem what about the basics :?: i.e. fuel getting through and spark at the plug are often overlooked.
A very rough and ready but effective method is to remove a plug and set it in it's lead with the plug body in firm contact with the head and then crank the starter - the darker the better and you will see and hear the spark if things are OK.
On fuel - disconnect at the carb inlet and crank if it's a mechanical pump or just switch on if it's electric - keep it brief on the starter or ignition switch as there should be quite a gusher if the pump is healthy.
In the interests of health and safety DO THE IGNITION CHECK FIRST AS RESIDUEL FUEL VAPOUR COULD EXPLODE and have a can to catch the fuel. Also have your garage fire extiguisher handy - you do have one don't you :!:
If both checks are positive it should start and run - simples If it fails either check, go into that system. Of course you could simply have run out of fuel :oops:
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JPB
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Re: Triumph Stag changed coil now won't start

#9 Post by JPB »

Connect the amplifier in accordance with the diagram pmd. Without that connected correctly, you'll find that it won't start - no matter what else you do. ;)
J
"Home is where you park it", so the saying goes. That may yet come true.. :oops:
Peter-109
Posts: 38
Joined: Tue Feb 15, 2011 7:06 pm

Re: Triumph Stag changed coil now won't start

#10 Post by Peter-109 »

Sorted! Lumentition module replaced and now all is good :) thank you for all your suggestions. :D
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