I think I need a new coil.

stratblue

stratblue

genoQian
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Greetings to the Collective.

I've been reading the posts on here for a while and some of the symptoms the bike has lead me to think that I 'need a new coil'. Sometimes I can smell an electrical burning odour when I stop and the bike has a tendency to feel a bit 'stallish' when slowing down and dropping into a higher gear, at junctions etc. It's died on me a few times just as I'm about to pull out. However, the problem is that I've no idea what 'needing a new coil' actually entails.

Is there one for each cylinder?

Do I need to change both?

How much are they?

Where on the bike are they?

Can a mechanical muppet like me do this job without reducing the bike to a charred husk?

Thanks, guys.
 
stratblue said:
Greetings to the Collective.

I've been reading the posts on here for a while and some of the symptoms the bike has lead me to think that I 'need a new coil'. Sometimes I can smell an electrical burning odour when I stop and the bike has a tendency to feel a bit 'stallish' when slowing down and dropping into a higher gear, at junctions etc. It's died on me a few times just as I'm about to pull out. However, the problem is that I've no idea what 'needing a new coil' actually entails.
Click to expand...

stratblue said:
Is there one for each cylinder?
Click to expand...

No Two per cylinder

stratblue said:
Do I need to change both?
Click to expand...

No, only the faulty one

stratblue said:
How much are they?
Click to expand...

Expensive for what they are. About 3 times more expensive than car ones. Shop around, but £70-£80 each would be about average.

stratblue said:
Where on the bike are they?
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They are sat on top of the spark plugs. Two are under the plastic covers that are on the rocker covers. The other two live under each cylinder head.

stratblue said:
Can a mechanical muppet like me do this job without reducing the bike to a charred husk?
Click to expand...

Can't answer that. No idea of your aptitude. You have to be careful not to break the plug connector. And be gentle removing the connector from the coil.

Your only trouble is diagnosing which one has failed. It might be obvious just looking at them, but not always the case. If they are breaking down internally then you have a 25% chance of getting it right. Not good odds considering how expensive they are.
In your place I would take it to someone who knows the bikes, that way you will only pay for the faulty coil, and not have to shell out for each of the 3 different types, if you were doing your own diagnosis.

Ian
 
One of mine failed a couple of years ago, low-speed running was terrible, lots of popping and farting on the overrun too. To work out which one was at fault, all I did was to let the bike tick over, then disconnected the low-tension connector of each coil in turn to see if I could hear any difference in the running. The pics I've attached show the upper and lower coils - depress the retainer at the red arrow, pull in the direction of the green and listen!

Pete
 

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i had very similar running issues although most of the time it ran and ticked over just fine, perhaps a little out of balance but it usually kept going, just stalling when hot ( a good sign its a coil). I suspected the lower left as when I removed the plug it was black and oily. Anyway I put in a "best offer" of £100 posted on eBay for a set of 4 coils which was accepted. Its a quick and easy job to replace the coils & leads and after a motorway run to clear the crap off the plugs and lambda it is definitely running better now.
 
I think I've read on here that the lowers are always noticeably 'muckier' looking than the mains, even when the bike's running fine - it was a lower that had gone on mine too. I always carry spare lowers and a main on the bike now, used ones off eBay cost me about £30 each - as you say, simple enough to swap, even at the roadside.

Pete
 
Dont rule out the throttle position sensor either.

There is a post in one of my threads thanks to another member on how to strip & clean it
 
Cols engine. Unplug both secondary coils at the connectors (see above). Start the bike and run for a few seconds. (carefully !) check the exhaust pipe temperatures. If one seems cooler its likely that is your weak coil. Swap the primary coils L to right and run the engine again. If the cool pipe moves you have found your weak coil.

Real life of course is never that simple but it's an easy test.

Another test is to pull out the Lambda sensors. The sooty one is the one with weak ignition coil(s). The unused oxygen from the misfire is interpreted by the ECU as engine running weak so it adds more fuel causing it to run arch leading to sooty Lambda sensor.

Disconnect the O2 sensor electrical connector before unscrewing the sensor. It's clipped under the cylinder and awkward to unclip so take care not to break the plastic. Dont touch the sensor head while it's out - they are very easily "upset".

If both are clean you probably dont have a coil problem.
 
stratblue said:
There are 3 different types? So it's not the case then that I could buy one and rotate it through the four locations to work out which the knackered one is?
Click to expand...

The main ones are the same each side, as per my first pic above. The secondaries/lowers, as in the second pic, are 'handed', so a left one won't fit the right cylinder and, obviously, vice-versa.

Pete
 
Bendy toy said:
Cols engine. Unplug both secondary coils at the connectors (see above). Start the bike and run for a few seconds. (carefully !) check the exhaust pipe temperatures. If one seems cooler its likely that is your weak coil. Swap the primary coils L to right and run the engine again. If the cool pipe moves you have found your weak coil..
Click to expand...
I wouldn't worry about assessing temperatures between the two cylinders .....
Once disconnecting both lower secondary plugs If the main coil sticks have failed completely it'll only run on one cylinder, and if it's breaking down it'll misfire on one cylinder. Unless both main cool sticks are fecked in which case it'll barely run or not at all.
 
Steptoe said:
I wouldn't worry about assessing temperatures between the two cylinders .....
Once disconnecting both lower secondary plugs If the main coil sticks have failed completely it'll only run on one cylinder, and if it's breaking down it'll misfire on one cylinder. Unless both main cool sticks are fecked in which case it'll barely run or not at all.
Click to expand...


Ok, disconnected the two lower coils and it seems to run fine. Any tricks for the lower coils? Thanks!
 
Strip & clean your TPS -

check one of my posts, theres a link in there...

if you think you need a new one £38 onkine (its a car one ;) )

I had similar symptoms = i changed to a SH cleaned TPS .. so far so good
 
stratblue said:
Ok, disconnected the two lower coils and it seems to run fine. Any tricks for the lower coils? Thanks!
Click to expand...

The lower coils are there for emissions purposes supposedly to catch any unburnt fuel from the main firing. They spark after the primaries so disconnecting them makes no obvious difference.
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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