Stickcoils-ectomy (would be the term I guess)

[vwdoctor]

Hello.
Just wanted to share some experiences with the forum. I have been reading a lot here and adv rider and various other forums so here is my contribution.
As we all know there are two different engines single spark and dual spark. They are mechanically identical except of course for the extra hole that was drilled in the head to accommodate the extra spark plug.
The electrical difference is that "central" spark plug is now being driven by a "stick coil" or COP (coil on plug). These stick coils are very unreliable due to the fact that they are not suited to the environmental of air cooled cylinder head (very hot). The bad thing is that they are failing slowly so you still get spark but it is very weak. This gives different symptoms but universally makes the engine run bad. This is due to the fact that the bottom plug does not provide good mixture burn (speculation), since it was never meant to be the primary plug. In fact I believe that the only reason to put the bottom plug in to "fix" the idle emissions. There is no change in HP from 1100 to 1150.
After dealing with TB sync and the rest of the usual tune ups to get the bike to run right I figured that at least one stick coil is bad (weak). It would throw the spark but only under 1/16 gap. In my experience this is not enough to ignite the mixture under most circumstances.
Being a cheap bastard I wanted to see if I can save some money and make the bike more reliable and simple at the same time. Two stick coils are about $220 currently, although the new ones have heat shield so they should last longer.

Here are the facts.
ON the single spark 1100 spark plug is driven by the coil, installed under the tank (waste spark) and all of that. This coil is carried over to the 1150 twin spark but is now used to drive the "bottom" plug. Stick coils are driven by a separate signal from the Motronic. Here is the key. THERE IS NO TIMING DIFFERENCE BETWEEN TWO SPARK PLUGS. THEY FIRE AT THE SAME TIME.
Everybody assumes that the spark plug timing is staggered but that would involve a lot of redesign on the Motronic side which I am sure BMW didnt want to pay for so they just took the cheapest solution possible (as always). I am basing this on the fact that if they

Solution.
Remove the stick coils.
Remove the spark plug wires to the bottom plugs.
Buy spark plug wires for the single spark bike (any 1100 single spaark). They are $60 from euro motoelectronics.
Install the spark plug wires and connect them to the central spark plug.
Leave the bottom plug alone. Dont remove it (obviously).
Tuck the wires from the COP anywhere you can safely hide them. Once you remove original wires you will be left with some clips you can use.
That is it done.
So far bike runs much better with no issues.
Open for questions or comments.

EDIT: picture added.

[kirby]

Ok, here goes. After 160K miles on my rock (bought new '04) I have only replaced the stick coils once and I am not really positive they were bad. The leads to the stick coils are far more prone to damage that can cause problems ,as the ignition is in series and if one lead breaks down you can lose both of the upper plugs.

My current set of coils have just over 80K miles..it runs perfect.

This bike is operated in the Mojave desert (where I live) allot in the summer with trips to Death Valley in a normal year. Also I do 14 hour days on the slab at 75/85 mph. Do a couple of track days a year.

I have heard it said that the coils cannot survive in the inviorment they are forced to operate....I don't believe this. BMW most likely would not put such a critical part on the moto without proper specifications to survive in the expected operating envolope and (knowing German engineering) without testing it to a VERY high degree.

For what its worth.

BTW I also operate allot on dirt/gravel roads here in the west.

mike

[vwdoctor]

Sounds like BMW should let you test their bikes for them. Either way, just sharing my observations so far regarding the spark timing. One of those, it is good to know just in case.

[timl]

The one time my stick coils failed I attribute to heat. It was a hot day and I got stuck in traffic build-up behind an accident. I may have sat at idle for 10 minute and probably should have turned off the bike. When traffic cleared I immediately knew something was wrong. The bike wanted to idle at 800rpm or so and sputtered at moderate rpm's although it ran okay at high rpm.

I drove it that way for perhaps a 500 miles - it was no longer fun to ride - before deciding to buy new coils. The problem was immediately cured with the new coils.

[kirby]

There is no doubt that components can and will fail..even new ones. That does not necessarily mean that the design is faulty. Clearly if you operate in unusuall circumstances it can cause overheat and other things. In CA we split lanes so are normally not "stuck" in traffic. When I am traveling elswhere and if I get stuck I will always shut down and have done that on all the aircooled machines I have owned.

My point is that there is millions of $$ spent to develope production machines. When you start modifying them..well thats the choice you make. When time comes to sell or trade...most!!?? mods will effect the value negatively plus the time and expense to do them.

Fun maybe...but in the long run what's all that fun going to cost you? Is it worth it?

mike

[vwdoctor]

I have no problem understanding that there are millions of dollars spent on development of parts and components but ultimately only time will tell if the design and implementation was a success. My point is that 1150 engine was single spark (1100) before dual spark so all of those components are tested as well. In my opinion there are no benefits to the rider with the dual spark 1150 and the entire purpose was to "win" a little on the emission - pollution control side but at the expense of the simplicity and reliability (due to additional components).So far (about 300 miles of riding) I didn't see any negative side effects and I did notice that the bike is running much better. Could this have been accomplished by just buying new coils, probably, but the way I look at it I backdated the ignition system to a known good, longer tested, reliable state.
I will keep you updated.

[kirby]

I have had single spark BMWs ( more than one), R1100GS and they ran fine.

But I believe that the dual spark was more about quelling the dreaded "surge" problem both from an engineering and marketing angle..This has been discussed at great length on more than one of the fourms that are specific to the oil head boxers during the recent past.
Over the years I have re-engeenered (sic) many products (vehicles mostly) and anything I say is just hearsay and hyperbole to any one else and that OK with me..just my ramblings. I have however been involved in several mechanical development projects in a professional way.


If your having fun I think that is good..just one man's opinion.

BTW I don't think you can get much more simple than a wire to a stick coil.

mike

[vwdoctor]

So far what I can say is that the bike runs excellent. I put about 300 miles on it in the past week and there is no surging, pulls strong no holes in the acceleration.
The reason for the modification that I actually have a bad stick coil. It is actually weak. The spark would jump only about 1/16 on inch. While this is enough to "have spark", it is far from optimal. I didnt want to spend $220 on stick coils which BMW as per TSB says to replace in pairs. Total cost on my end is $60 and I get brand new spark plug wires. Additional labor was almost nothing since the tank was of due to the ABS removal at the time.
Bottom line "from the field" is very nice riding bike for minimum costs and increased serviceability.

[sweatmark]

Interesting project.

BMW's only rationale for dual-sparking was impending EU emissions regulations, according to everything I've read. Note that the dual-spark R1150 bikes gained NO power or torque improvement over single-spark versions.

[vwdoctor]

My point exactly. From my understanding of the industry it is always emissions that dictate changes because you must comply with the law first. Everything else is secondary. From the design standpoint if BMW was "close" to meeting the numbers and adding another spark plug accomplished this for them (at idle mostly) the easiest way is to just use the existing components, drill the head and shoot another spark. Now this is still unverified by measuring but logically since there is no need for emissions "fixing" in the upper ranges there would be no need for BMW or Bosch to play around and add twin spark individuality . It is also cheaper which is the main driving force in anything nowadays.
While it would be nice to show that the sparks are fired at the same time using o-scope, seat of the pants feel is good enough for me (until something blows up)

[kirby]

Quite right!

Not only does the R1200 have two plugs per cylinder..it... Gasp!!! has two stick coils as well!!

What were they thinking???

mike?!

[vwdoctor]

But that engine was designed from the beginning to be twin spark engine, with two stick coils , and engine control to use two spark plug timings. I would never even try to do that to 1200 since it would be "butchering" the bike, but it wouldn't run well anyway so what would be the point. R1150 engine was designed to be single spark and only later "adapted" to be twin spark engine. It was never the original intent. It was a stopgap measure until 1200 was out. I guess the emissions laws caught up too quickly. Trust me I am one of the most skeptical guys when it comes to "engine mods" on a budget but in this case there is no downside to it, for me at least. I do appreciate the questions though, if there is a flaw in my thinking I would like to know.

[vwdoctor]

And guess what? 2013 R1200gs is single spark. What gives?

[kirby]

There is probably no point in debating about this but I can say a couple of things.

The 1100 should have had dual spark but didn't as they were known for surging which drove the type A's crazy. BMW then bumped the oil head up to 1150cc (1130), and added the second plug to help with better combustion which helped in the epa requirments and did allot to stop the surge. With just over 500cc per cylinder its a large combustion chamber and dual spark does help. They had to add the plug in the bottom of the head 'cause a complete redeisgn would have been necessary to do it in an optimal place so its not as efficent as it would be if it were. BTW the R1200 plug position almost exactly the same as the 1150. Designed for dual ignition??? If it were the plugs would be different position.(my guess).

As an example of a engine with dual ignition is the O-200 cont. aircraft engine. Although the bore is a bit larger than a (1150) the principle is the same. If you turn one of the (Dual mags) mags off it will drop 100+- (at 1750 rpm) rpm. That fact tells you that the combustion is more efficent with dual ignition. If you turn one of the mags off at full power the engine will run rough and more than 100 rpm loss. We are talking dual plug combustion not redundacy which the dual ignition contributes to both. I have run my engine without the bottom plugs firing and I could tell the difference.



Further..when I modified my Moto Guzzi CX 100 (just over 900cc) with dual plug heads the first time I started it the idle was up by 150 rpm and since that time the fuel milage is better.(No other mods except tuning)

Look, bottom line is if you want to run single coil single plugs then by all means ....My point has always been that the statement that the stick coil was not designed for or had the correct specs is faulty..I have heard this tale for years, and I have had no trouble with mine and I know others with the same experence. I'm sure there will be people that will say that they only last a few thousand miles...and are not suitable... won't dispute that how can I? Just know what my experiences are.

I have over 250,000 miles on the 1150s' Have had them completely apart..They work for me.

mike

[vwdoctor]

So do you think that there is a change in idle RPMS of the dual spark 1150 if the bottom plug is disconnected (of course safely) at idle? I haven't noticed. If twin spark was more efficient that there should have been a change in the engine power which there isn't. 85hp for both. And as far as surging goes there is plenty of twin sparks out there that are surging so that is probably more related to other factors (TB sync, valve adjustment, bad stick coils and such)

BTW love the opening remark.
"There is probably no point in debating about this but I can say a couple of things"

[kirby]

So do you think that there is a change in idle RPMS of the dual spark 1150 if the bottom plug is disconnected at idle? I havent noticed. If twin spark was more efficient that there should have been a change in the engine power which there isn't. 85hp for both.

The bottom plugs quit in an all day run in HEAVY rain mostly hi speed. I noticed a drop in fuel mileage(about 2 mpg) but never noticed the idle change. The coil failed..very rare. Got me home on the uppers..about 450 miles I figure from when my mileage droped.

HP is measured at the brochure.

mike

[vwdoctor]

Either way I appreciate the input. Don't mean to stir up stuff, just looking at things from a different angle I guess.

[kirby]

All of us here to learn from other's experience and try to see thru the myth..

cheers
mike

Edit:

Forgot to mention that the '13 GS has a totaly different engine as in liquid cooled heads, which means a different combustion chamber design!

I like it!

mike

[vwdoctor]

One quick question. You said you double sparked your Motoguzzi. Are you saying you are better than the Italian engineers but not as good as the Germans? Why would you mess with the design that millions of lirras were spent on. If Italians thought that the engine should be double spark I am sure they would have made it as such.
On the new 1200 engine topic, yes it is completely new design but if twin spark is always better, somebody should double spark it pretty soon.
There are plenty of myths out there I guess.

EDIT:

I do appreciate the input and it is making me read up more about the reasons for dual spark usage in general.
And the new 1200 will be the difficult to improve given that they finally added water cooling (somewhat) and wet clutch. Very nice compact design. I thing that engine will be around for a while, probably until direct injection comes along to bikes (god help us)

[kirby]

Funny,
Well the Guzzi engine in my Le Mans was designed in the 40's (really the basic design from the 20's) and it has what is called a "heron" head... basically an antique. (with points)
The head was for the 500/650/750 cc engines and when they punched it out to 948cc the flame travel was not so pretty good for the bigger combustion chamber. The racing guys came up with the dual plug version which works good and is easy and cheap as using the same ingniton coil..just adding wires. Lots of $$$ spent in development. (for the conversion just drill the plug hole on a mill and thread by hand).

The liquid cooled head on the new GS has a state of the art quench that puts the mixture in the exact right place to be ignited by one high energy ignition source and is cheaper to manufactuer 'cause of fewer bits...whew!!! my brain is in overload.

My Guzzi is a throw back to another time...that's why most discribe the engine as better suited for a tractor...but not knowing your vintage ... you may have never seen one in person..few have. You ride with your knees in your face and all humped over..ugh... not good for the long haul. If I have to go somewhere down the road and need to be there with some reliability..its the dual spark beemer. (most dependable single track machine I have ever owned).

But it(the LeMans) sounds wonderfull and is weird like me, also not intended for the mechanically challagened.

Have a nice day!

mike

BTW Nobody is better than the Italian designers..just ask them!