My biker started to misfire today - another coil fail case?

[grwrockster]

Hi. I would appreciate if anyone could confirm (or refute) my hesitant diagnosis before I spend the cash on a new stick coil.

Bike started running a bit rough, tickover slightly lumpy and it gets worse at 5k revs and larger throttle opening. So, having read some of the advice from members here, I did the following:

1. Removed both secondary plug leads (engine would start but ran v rough - definitely missing badly)

2. Removed RH Primary plug lead (Bike started and ran on LH pot ok)

3. Removed LH Primary plug lead and replaced RH (Bike would fire on RH pot but not actually start)

4. Tried running the bike more with secondary plug leads off, but it ran too badly to contemplate riding it.

Bike will still run pretty well (I rode it home 40 miles) but it's definitely missing and down on power - the wallop that should be there when you give it some gas at 5K revs has gone fishing.

On the basis of the above, I'm thinking that the RH stick coil is breaking down? Looking at the stick coild, the LH one is showing signs of corrosion, but from the above it seems that it's actually the one that looks fine that is on the way out (if I'm right of course).

So, before I had Motorworks or someone £70-odd for a new one..... do you clever lot out there think I've made the right diagnosis?

I saw the previous post on the same subject, and was intrigued by the Ford coil mod. However, I have no idea of part numbers or even if the coil that the clever guy in the states used is even available here, so keeping it stock is probably the way to go? BTW - these stick coils have to work in a very nasty environment for electrics - it must get VERY hot in that cyl head recess - is this why they age and break down so early in life? I've never had an issue with a coil going on any other bike I've owned in 30 years!

Oh -in case it's relevant..... The bike is an '04 Twin Spark and has just (today) rolled over 30k miles.

Thanks in advance of any sage-like advice and support!
Graham

[04rocksterorange]

hey there,
my bike had recently had the same issue, ie, running like shi! above 5 grand and a hesitation on full throttle opening. i replaced the stick coil on the rh cylinder which was visibly rusted and corroded, and my oh my what a difference!! give it a try and i would also recommend a throttle body balance and while your in there doing that do a idle adjustment as well. hope this helps!!!

cheers mate!
bryan

[grwrockster]

Thank for the reply Bryan. I had another short mess with the thing today - and removing the RH primary with the motor running made no difference, while the LH one does.

I replaced the plugs yesterday in the vain hope, and checked the connectors to the stick coils as well. I have a multi-meter in work so i can always check the coil resistance across the terminals - dunno the values but if the LH readings are different to the RH then that's pretty much gonna seal the deal (I'm pretty confident it's the coil now tho - thanks for the info of yours having the same symptoms).

The bad news is that the LH coil shows corrosion, but the RH looks fine but doesn't work - so I can see 2 new units in my near-future, and an empty wallet!

BTW - I did a TB synch and Idle speed 4 weeks ago - mind you that was 3500 miles and a continental jaunt ago. I suppose it could've packed up in Austria (but the bike was faultless and great over the Stelvio, Grossglockner etc.) so if it had to happen now is the lesser evil I suppose. I have checked the cables to ensure they are seated and there's no problem with them, but I'm sure the issue is with the sparks.

[jfslater98]

Howdy,

When I suspected one of my coils failed, I too tried to test its resistance against a new one. Couldn't find any difference between the two, nor could I find any info on what they should read. Maybe your Google-fu is stronger than mine.

My memory of testing the coils was to remove the secondary's one at a time - remove the left side 2nd, see what happens. Put it back. Remove Right side 2nd, see what happens.

But if you're seeing corrosion, it's probably time to replace. I had heard that the newer ones are less prone to failure, hopefully that holds true.

One last piece of advice before I turn in: be sure to remove the lead wire from the coil FIRST, before removing from engine. If you break the connector, the entire expensive wire leading into the motor must be replaced. The heavy-ish coil can put more strain on the connector.

Good luck!

[04rocksterorange]

like jfslater said, the new coils are better, if yours(old ones) are white they are old and get way way hot, the new ones are black and hold up better.......mine was the black one that corroded. so take it for what it is worth. and as for your little jaunt......dam you i am so jealous!!!!! it is sometimes better to change both at the same time, a mechanic friend told me they one changed a bad one and nothing happened, changed them both ran sweet, best of luck to you, do you have any pic of your ride?

cheers!

[riceburner]

Replace them both.

When you put the new ones in smear them with Hi-temp silicon grease, it'll give them some protection against corrosion, and make them a DAMNED site easier to remove in the future.

If you replace both you know you've got 2 good ones on the bike, and a spare left over if you need it. (make sure you keep the good one. )


oh - and don't forget the take the little connectors off the coil-caps BEFORE removing them - it's quite easy to break the silly little DIN connectors if you don't.

[grwrockster]

Thanks everyone for the replies.... RB - I'm sure you're right about changing them both, but I checked in AFTER I'd already given my money to Motorworks for just one. I did think about the 2, but abject poverty after gallivanting around recently, plus running over a large piece of glass or metal and slashing a half-worn Z6 rear and wrecking it (3200 miles on it and it was looking to have at least that left in it again - Grrr)the week after getting back to the ole salt mines has made me defer the inevitable purchase of a 2nd stick coil until a later paycheque.

I also figure that by buying only SC then if it's not the cure to the ailment then at least I've only spent half as much as I might've before heading in a new direction. I will be getting another one though for sure.

My SC's are Black ones, not white btw. I was hoping that new ones would be improved and last better than the originals, but from the sound of it that may not be the case? if so, damn!

As for disconnecting them before removal... I confess that I haven't done. I do however gently lever the coils out with a flat-blade screwdriver rather than the puller gadget. I find this is far easier and more progressive and your less likely to yank it out with a jerk while landing on your backside. Then I carefully hang the stick coil over the gearlever or brake lever if it's still on the lead - this stops it swinging about in harms way and supports it - or I unclip the connector once it's free of the rocker cover once it's easy to get at.

I'm guessing that it's the heat that's seeing these stick coils off - electronics/electrics generally don't do well at all in high temps and age or throw a wobbly, while cooler temp envoronment stuff keeps on going. I've had the idle thought that, rather than go to some massive effort to alter the set-up, coils and wiring to accept other kit.... - would it be possible to get a 'high-tension extension Lead' of sorts? I mean instead of the Stick coil being seated in the head, mount it externally and have an extension lead going from the SC to the plug. I bet they'd last a lot longer without being baked to death all the time! Anyone think this is this possible / a good idea? has anyone actually tried it, and if so, did they 'make up' or manage to locate a suitable extension lead (I was thinking of the old-style Distribution cap centre leads from the HT Coil on a car to the Distribution Cap or similar as my inspiration). You could run the 'extension' throught the plug spanner centre so it's already on the plug when you fit the sparking plug in the engine, then simply plug the other end into your nicely located cooler-running Stick Coil. what do you reckon? Any thoughts anyone?

Finally.... yes O4RO - I took loads of pics of the Austria Trip where we rode the Stelvio (twice), the Fluella Pass and several others en route to Grossglockner, Nochalmstrasse and the Vrsic Pass in Slovenia etc. - really enjoyed the 10-day trip. I'll have to try and figure out how to post them on here though - I haven't the faintest idea how to do it!

Thanks again to all of you for the assitance!

Graham

[04rocksterorange]

hey my email is woodsman.whip@gmail, if you want to email me some pic i would love to see some pics, thanks and happy to see your bike is once again happy!!!

[riceburner]

Graham - I share your thoughts about the stick-coil - remember they're also getting exposed to far more moisture than the environment they were originally designed for (under the bonnet of a 3-series..).

The newer ones are (I think) a grey colour?



I've had thoughts about stripping the system off and replacing it with the sparking system from a single-spark R1100R - the single sparks use a central coil and HT leads with proper "old-fashioned" plug-caps. I don't see why it shouldn't be possible to take the low-voltage firing signal and feed it into a traditional coil and HT lead system.

After all - the Twin-sparks already have a trad-coil and HT system fitted......
What I don't know yet is if the Motronic measures the signals being generated or anything like that and so by going from the coil-caps to the trad-coil system you'd be upsetting it and generating enough error-codes to stop it working properly.

[grwrockster]

RB.. My new SC turned up at work this am from Motorworks - but it's Black, like the original. So, I wonder if this means that I've not got an 'improved' product and I can look forward to another fail somewhere down the line? if so - DAMN!

Also, I share your concerns RB about messing with something I didn't understand well enough, which is why I thought of the 'extension' idea - this doesn't mess with any of the OE set-up (well, I suppose there'd be a tiny increase in Resistance over the circuit, but I doubt the system is anything like sensitive enough to be affected).

I'd still love to know if anyone has tried this idea out (or maybe one day I'll see if I can suss it out myself - you never know - I'm well handy with some zip-ties and waterproof spray y'know ). Less than 2 feet per side of HT Lead/connectors hidden away under the covers - and away you go?

I know the SC's are in an environment more susceptible to damp than under a bonnet, but would have thought that (apart from short trips making them 'sweat' perhaps) that it has to be the far greater peak temps of the air-cooled heads that prematurely ages the windings and sees them off (despite not being enclosed under a bonnet, I bet the temp the SC's have to endure in situ is way higher than in a w/cooled 3-series engine)??

I wasn't aware that these SC's started life on a 3 series car (tho guessed they were on one of them somewhere/sometime). I wonder if the 'car part' is cheaper than the 'bike part' to source - it wouldn't be the first time eh? I bet they have a different part number to confuse the issue too!
I did some quick 'research' on the Net and there are VERY similar-looking BMW car coils (different 3-pin plug, but otherwise very close) - and you can buy them for less than HALF the price of a bike SC. has anyone tried a 5 Series or similar coil to see if it could be made to fit?

Intriguing stuff. Answers on a postcard please.....

[sweatmark]

Some pertinent stick coil info:
http://www.advrider.com/forums/showthread.php?t=716626
http://www.advrider.com/forums/showthread.php?t=713106

[grwrockster]

SM - Thanks for those links. The thing is... I'm not sure I'm able to go quite that far - i doubt my skills and enthusiasm are quite up to this standard! In any case, here in the UK I'm fairly sure we don't have the 5.4 Ford F-150 (guessing that's a 5.4L pick-up or SUV or similar here?) - the way our fuel is taxed you'd need to be Bill Gates to afford to run the thing! Those coils may well be fitted onto another Ford we do have - but I'd have no idea how to find out what. I do like the solution though !

I'm most intrigued about how simple it would be to use the BMW car SC's instead (which are Grey btw - does this mean updated/better?? There's a LOT on the Net about Stick Coil woes on BMW Cars, so I bet the factory reacted to preserve the rep of their 4-wheelers, cynic that I am). Car SC's are far cheaper, and maybe a simple harness could be made to swap from the 3-pin fitment the bike SC has, to accept the different 3-pin on the 'car' SC? The mod may or may not improve reliability, but at least if you lost one the replacement would be much more widely available on shelves and not more than half the price from what I've seen on the Web.

I'm also still pondering on my simple 'extension' idea - my gut feeling is that it is being confined in that hostile (for electrics) cyl head environment that the SC's can't cope with for long.

At least I have some positive news. The new SC arrived yesterday, and I popped it on when I got home. I've only run the bike on the stand (hammering down with rain and had to go straight back out) so no test ride yet, but it seems to have done the trick .

[grwrockster]

Well, I think maybe RB was spot on, and I should have just bought a pair of SC's from the outset. I took the bike out for a quick blast last night. It is a LOT better, but I feel it hasn't quite got the spuds that I feel sure it should have at the top-end.

So I'm theorising that maybe the other stick coil isn't 100% as well. Dammit! I guess the ole wallet will just have to come out again!