Secondary sparks - what do they do / not do ?

[Paul90]

Hi,

Bike in question is a 1200 GS, 2006

Does anyone know for sure what the secondary sparks do ?
I'm guessing that they ensure a more complete burn and therefore reduce emissions and (perhaps) extract a little more power. I'm also guessing they should spark all the time at the same time or just after the primary sparks.

However, I've also read (on a Forum) that they only spark at certain revs / load conditions, which seems odd.

I'm asking as I'm trying to pin down a very intermittent misfire, which sods law ensures disappears when I start changing things about to isolate the offending coil (that's what it feels like to me).

If you have any info on the secondary sparks that may help but please say if you know for sure by experience / reliable source or are just guessing or repeating some dealer sales waffle ;-)

Many thanks,

Paul

 

[max7]

Whole load of info for you here Paul. Think the thread answers most of your questions

https://www.r1200gs.info/forum/2-general-chatter/4442-secondary-spark-plug.html

 

[Paul90]

Cheers, will have a read.

 

[Paul90]

OK, so that suggests the secondaries would fire all the time but not necessarily with enough advance to make the engine run nicely if only the secondary coils were connected / working.

So, a slightly different question.
How should a bike with just the secondary coils connected feel to ride ?

I was thinking of running it for a week or so just on the secondaries to see if the intermittent fault might show itself.

If the coils weren't such stupid money I'd just buy a few and swap them around.

Paul

 

[max7]

Cheers, will have a read.

I'm sure you know this already (you've clearly been about a while) but you've plenty of techie types to refer to if you've still got any unanswered questions. Some helpful soul will come to your rescue.

 

[Steptoe]

OK, so that suggests the secondaries would fire all the time but not necessarily with enough advance to make the engine run nicely if only the secondary coils were connected / working.

So, a slightly different question.
How should a bike with just the secondary coils connected feel to ride ?

I was thinking of running it for a week or so just on the secondaries to see if the intermittent fault might show itself.

If the coils weren't such stupid money I'd just buy a few and swap them around.

Paul

Well why not just disconnect the main coil caps and run it on the secondary’s - you won’t notice any difference until the revs go beyond 4K revs, when everything stops happening . Or simply test the main coils by disconnecting both secondary’s and check if it runs on both sides with just the mains.

 

[TLSgazza]

When one or both of my main coils were malfunctioning last year, my 06 wouldn't run with anymore than a trickle of throttle at low revs.
It wouldn't rev past about 4.000 rpm as steptoe says above. I managed to nurse it for 1.000 miles or so through France at the time to get home not knowing at the time what the problem actually was.
2 new main coils fitted after a trip to mikeyboy to diagnose the problem and it's been fine ever since.
My secondary coils have been on the bike from new. Almost 105.000 miles now. The mains only failed at around 90.000 miles.

 

[Paul90]

Tried it with just the primaries connected and it seems to run fine so it doesn't seem that they are a problem but it is an intermittent fault so it's possible they were just working ok on the fairly short test run.

When it does play up it's normally low revs / lumpy tickover, which seems to point to the secondaries ?

Tried it on just the secondaries and it didn't feel so eager to rev and wasn't quite so smooth at low revs but nothing too bad.
If I really gun it then it all stops happening for few seconds
Again as it's intermittent perhaps they were working fine and not being quite so smooth at low revs is normal ?

Next time it plays up I'll disconnect a pair of coils and try again.

Thanks for the help and suggestions so far.

Paul

 

[Kersidan]

It might be worth trying a new set of spark plugs (x4) if you haven't already. I had an intermittent misfire on my 06 GS a few years ago and it was one of the plugs with a hairline crack in the ceramic insulation. New plugs cured it strait away and cheaper than a new set of coils.