Stick coil replacement?

'04 R1150R craigslist ad *link* says this about the bike:

Upgraded spark plug coils with 2 x F150 coils, no longer need expensive stick coil.

I have looked for info on this mod but haven't found anything. Anybody know anything about this? I have often wondered why BMW designed it this way.

I promised myself I would persue this the next time one of my stick coils failed...

https://advrider.com/index.php?threads/coil-sticks-no-more.713106/

'04 R1150R craigslist ad *link* says this about the bike:

Upgraded spark plug coils with 2 x F150 coils, no longer need expensive stick coil.

 

I have looked for info on this mod but haven't found anything. Anybody know anything about this? I have often wondered why BMW designed it this way.

Afternoon Lee

That mod has been around for a few years now. It seems to work but I don't have any info on how long it works as I haven't ever done it myself or personally know of anyone that has done it.

My concern would be how much load those coils put on the coil driver electronics in the Motronic. (might not be enough extra load to matter or could be enough extra load to shorten Motronic life).

Dirt - Post 327 and 328 of the above link relays a few experiences related to your concern.

Lee - Another option mentioned that appeals to me is relocating the OEM stick coils to a more friendly enviroment as mentioned here:

http://www.ukgser.com/forums/showthread.php?368817-Stick-coil-about-to-burst-!&p=3778322#post3778322

Lee - Another option mentioned that appeals to me is relocating the OEM stick coils to a more friendly enviroment as mentioned here:

From the fiche pages it looks like BMW has continued stick type coils on 1200 & 1200W bikes. Wonder if they are working any better there.

I know they use them on the K1600 and they are known to fail in that application. Can't speak regarding the 1200 but I'm sure someone will.

'04 R1150R craigslist ad *link* says this about the bike:

Upgraded spark plug coils with 2 x F150 coils, no longer need expensive stick coil.

 

I have looked for info on this mod but haven't found anything. Anybody know anything about this? I have often wondered why BMW designed it this way.

Lee, my opinion is that this is a weak solution looking for a problem. Between the load on the Motronic, unknown inductance of the coil, marginal dwell time to the stick coils as it is, and extra electrical noise, if it were me and I liked the bike I'd just return it to stock. And it's an ugly solution too.

 

From the fiche pages it looks like BMW has continued stick type coils on 1200 & 1200W bikes. Wonder if they are working any better there.

Morning Lee

The BMW 1200 (hexhead) uses the same stick coil as the 1150 for the upper stick coils. There have been some upper stick coil failures on the 1200 hexhead but not nearly as many as on the 1150 oilheads.

BMW changed the stick coils to a more robust coil at some point in their life (didn't change the part number though, that I know of anyhow) so the later 1200 stick coils & the 1200/1150 latest replacement stick coils appear to hold up much better (much longer) than the original failure prone stick coils.

It is difficult to test a stick coil for being poor, decent, good, or great due to isolated secondary so some get replaced just because the rider or technician can't reliably test them.

From what I have seen in the past, this is on the later 1200 (hexhead) & later replacement 1150 (oilhead) stick coils, is very few failures, & on the very few that I have seen that failed most were due to improper coil removal with the wire pig tail still attached, or damage during the pig tail connector removal, or using non approved spark plugs with wide electrode gaps that forced the coils to arc internally. (the small diameter BMW stick coil uses an isolated secondary & an externally grounded RFI shield so the RFI shield is not very far from the coil windings therefore if the coil is forced to spark across an extra wide spark plug electrode gap the spark can also arc to the internal RFI shield)

The early 1200 stick coils & most 1150 era stick coils didn't do well with moisture intrusion so power washing, or even direct garden hose spray, into the cavity on the front of the cylinder heads (that cavity goes back into the upper spark plug area) on a HOT engine allowed the cylinder head & spark plug to quickly cool & suck some moisture into the coil then the coil could either corrode inside or arc internally causing an eventual coil failure. Same with a high pressure direct spray onto the plastic spark plug well cover on a hot engine as it isn't sealed to the valve cover. (I have cut a few early stick coils open & even on some that were still working OK they had visible corrosion inside).

The one thing that the BMW 1200 has over the 1150 is it doesn't use a lost spark ignition system so the spark plugs in the 1200 get half as many sparks per mile per RPM (ie don't spark every piston up) so the 1200 spark plug electrode gaps don't grow as fast as on the old 1150 lost spark engines. Not a big deal but something to keep in mind on 1150 bikes that go long distances between spark plug changes or are using non approved single electrode spark plugs.

If a rider or technician is (always) careful in how they remove the coil pig tail and/or just gently pry the coil out with pig tail still attached instead of using a darn coil puller, then uses a good dialectic grease to seal & re-install the coil, & uses an approved electrode gap spark plug then I see no reason that the latest BMW replacement stick coils won't last a long long time.

Thanks for the replies — all y'all are awesome!

And it's an ugly solution too.

$171 each with questionable reliability is pretty ugly too.

Just thinking out loud - I wonder if the lower plug coil P/N 0312137671712 could be used similiarly to the Ford coil... seems it would eliminate the motronic compatibility concerns.

And it's an ugly solution too.

 

$171 each with questionable reliability is pretty ugly too.

 

Just thinking out loud - I wonder if the lower plug coil P/N 0312137671712 could be used similiarly to the Ford coil... seems it would eliminate the motronic compatibility concerns.

The Motronic has three coil drivers. One is for the large lower plug coil and two are for stick coils. The dwell time on the stick coil drivers on the R1150 is quite short (1 mS) which is half what the dwell time for the same coils on the R1200 is. Determining whether the stick coil drivers are sufficient for the lower coil is an engineering project that I haven't seen yet.

A better way to improve a dual-plug R1150 is to add a 2nd Load Relay to power the stick coils directly from the batter rather than through the key switch. That boosts the voltage and helps with the short dwell time.

Beru coils are $130 at beemerboneyard, with a discount possible if your an MOA or ADV member.

 

Just thinking out loud - I wonder if the lower plug coil P/N 0312137671712 could be used similiarly to the Ford coil... seems it would eliminate the motronic compatibility concerns.

It could BUT you end up with the same Motronic compatibility concerns (see Roger's post just above)

If you try to drive that coil off of the existing lower sparkplug-coil Motronic driver that then places a double load on that Motronic driver.

If you try to drive that lower coil from one side upper stick coil Motronic driver then that could overload that driver (might work & might become a long term issue that fails the Motronic miles from home after a long extended high speed run. I'm not sure the stick coil dell time would even work that well with a BMW lower coil as it is an entirely different coil design. (see Roger's post above)

The BMW stick coils are not cheap but a Motronic failure far from home is more expensive & could ruin a trip.

Plus, replacing the stick coils with some r*d-neck jury rig would probably take more money off of re-sale value than any coil money savings.

If you ever had to have a BMW dealer do a runability type repair on the road they probably wouldn't work on it until they converted it back to stock coils anyhow.

One thing I thought about years ago (when the early stick coils were failing early & often) was looking into a Harley 4 tower coil (used on 4 plug conversions) or using a BMW single plug engine to dual plug head conversion coil (this coil we know works as it has a fairly long proven track record).

Beru coils are $130 at beemerboneyard, with a discount possible if your an MOA or ADV member.

+1

And they are even cheaper when purchased in pairs. My 12-year-old stick coils both failed within a short period, and so I bought the Berus. You need to swap over the rubber sleeve, but otherwise they are direct replacement. So far, in a year and ~5k miles they have been fine.

A better way to improve a dual-plug R1150 is to add a 2nd Load Relay to power the stick coils directly from the batter rather than through the key switch. That boosts the voltage and helps with the short dwell time

I did this mod on my backup RT which did not have the factory installed 2nd load relay. It did improve starting and idling to a degree. This does not address stick coil reliability however which in my mind is the intent of relocating the coils away from the cylinder head.

Again... next time I have a coil failure I'm going to look further into an alternate or relocated coil setup.

It could BUT you end up with the same Motronic compatibility concerns

All good points, not concerned with resale or dealer however...

If the technical details could be worked out I know the mod could be done in a professional manner and look proper. Hopefully I'll not have another coil failure... I've replaced two so far. If it does occur I'll use the Rockster as the test mule.... I stay local on that.

It could BUT you end up with the same Motronic compatibility concerns

 

All good points, not concerned with resale or dealer however...

 

If the technical details could be worked out I know the mod could be done in a professional manner and look proper. Hopefully I'll not have another coil failure... I've replaced two so far. If it does occur I'll use the Rockster as the test mule.... I stay local on that.

 

Morning mark

If your current coils are of recent manufacture then they shouldn't fail as long as you can keep the moisture out of them. Use a good quality spark plug dielectric grease to seal the spark plug porcelain's to the lower coil boot & use a dab of dielectric grease to seal the wire pigtail connector to coil area.