Plugs & Coils & & Compression & Stuff

So I have another thread going on what maintenance should I be doing on a new to me bike. But this is a bit more specific...

The bike is a 2011 DOHC with 63K miles and I am in the process of giving it a complete once over, service and refresh etc.

Today, a thin walled 14mm socket arrived, so it was time to replace the plugs. Easy enough job even if the secondary ones are a pain to get to.

Looking at the secondary coil packs however - one of them (LHS) looks burst and corroded and has a crack in the plastic cap:



The RHS one has a slit in the metal casing which is presumably just how it's manufactured and a slight bulge to the plastic at the right hand side of the photo - I am not sure if this is normal, or it is on its way out as well? Can anyone advise?



The primary coils are perfect, but they have much more weather protection. Anyway....a new coil or two are obviously required.

Which brings me to....where is the best/cheapest/fastest place on the web that UK GSers recommend? So far I have used motorstorm for service parts and bought the coil pack remover and thin wall plug socket from Martin Iles.

Anyway.....the old plugs looked like the picture below. The order is left cylinder Primary, left Secondary, RP, RS. The Primary plugs look good to me, but the secondaries are much darker. Not sure if this is normal or if thy just weren't firing due to knackered coils. Any thoughts on this from experts?



So that's plugs and coils dealt with, next up is the cylinder compression. I have a compression tester, so may as well run a test to see where the top end is at.

Given that each plug has it's own coil pack, for a compression test is it OK to simply unplug the connectors that go to each coil pack and run the test using the primary plug hole in each cylinder? I don't see any reason why not, but thought I'd check if anything needs to be grounded out perhaps?

Anyway....thanks in advance from a GS newbie!

Replying to my own post, it looks like the coil part numbers are:

12 13 7 715 857 for the left and 12 13 7 715 858 for the right. And they are bloody expensive!

Which brings me back to the question above about best place for parts! Or does anyone have a set floating around they would part with for a reasonable price?

I could be wrong, but I think the OEM coli sticks are reasons my priced. BUT have a search on the web for compatible car alternatives. Search for Beru items - be aware this might only apply to the primary as the angled and handed lower coils are a little less 'ordinary'.

Motorworks is another place to look - they do have secondhand stuff if you call them.

For the plugs, the secondary/lower plugs always look a little darker...

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Slipperyeel said:

I could be wrong, but I think the OEM coli sticks are reasons my priced. BUT have a search on the web for compatible car alternatives. Search for Beru items - be aware this might only apply to the primary as the angled and handed lower coils are a little less 'ordinary'.

Motorworks is another place to look - they do have secondhand stuff if you call them.

For the plugs, the secondary/lower plugs always look a little darker...

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Thanks! Looks like I can cross reference Beru coils for newer bikes - looks like ZS384 for the right secondary and ZS385 for the left. They aren't cheap either - around £80 or so each. Versus around £100 each for new BMW parts.

I also presume I should really replace both of these - if the right hand side one is still working, the bulging probably indicates it's not going to be far behind the left hand side one in bursting

A look at the second hand market gives me a couple of options - £55 for a pair from Lithuania, or £79 for a pair from James Sherlock bike breakers.

Interestingly, the Sherlock ones have a stainless shell vs the painted steel shell of my ones. And if I look at the part numbers, the Sherlock ones are the same, but have an -02 suffix vs the -01 on mine. So presumably BMW noticed a problem with water and revised the materials to stainless at some point. If I read the markings right, they have a '16 manufacturing date vs. '10 on the ones I pulled out of my bike.

Genuine 147 dollars each for the cheap ones
BM specialist 110 and 120 quid each
Beru 55 quid each, all the same price harder to get the lower ones,
Beru same ones, all the same price, next cheapest is M&P wales at 80 each

either way total robbery VAG set of 4, same technology, same manufacturer £44 a set

I wouldn't do secondhanded unless low miles and under 5 years old.... everything electrical in the motoring world is designed to fail rubbish these days

botus said:

Genuine 147 dollars each for the cheap ones
BM specialist 110 and 120 quid each
Beru 55 quid each, all the same price harder to get the lower ones,
Beru same ones, all the same price, next cheapest is M&P wales at 80 each

either way total robbery VAG set of 4, same technology, same manufacturer £44 a set

I wouldn't do secondhanded unless low miles and under 5 years old.... everything electrical in the motoring world is designed to fail rubbish these days

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Where did you see the Beru ones for £55?

I probably would have bought a pair that price - but I already ordered the secondhand ones from James Sherlock. They seem to have manufacturing date codes of October 2016 though. The ones I pulled off my bike earlier have date codes of October 2010 - which makes sense as it's a 2011 bike.

Oh well - I'll make sure to measure the resistances when they arrive.

adm1 said:

Where did you see the Beru ones for £55?

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I just found some for that price - spark plugs.co.uk - but, not in stock and phone to confirm availability before ordering. I'll give them a call tomorrow just to see, but in any case I at least have the second hand ones on the way....

he stocks the main ones by Beru, and says the secondary ones he can get are Beru with a Champion sticker.... when you look hard (for Champion ignition coils) you'll see they are owned by federal mogul (who also own Beru)

I'd run the iridium plugs NGK DCPR8EIX bit better last more than twice as long

Well, the new (second hand) secondary coils turned up this morning. They look almost new, which is nice.

Chucked them on the bike and all is good!

botus said:

he stocks the main ones by Beru, and says the secondary ones he can get are Beru with a Champion sticker.... when you look hard (for Champion ignition coils) you'll see they are owned by federal mogul (who also own Beru)

I'd run the iridium plugs NGK DCPR8EIX bit better last more than twice as long

Click to expand...

These plugs do not fit the TC , the op says his bike is a 2011

Mistacat said:

These plugs do not fit the TC , the op says his bike is a 2011

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Oh sorry if that's the case, thought I'd read they had the same plugs in both the 2007 and later up to 2011 bikes?

https://www.ngkpartfinder.co.uk/mc_extra.php?id=527 looks like the up to 2007 is 12mm thread and the later one 10mm thread then?

Yes.
04 to 09 12mm DCPR8EKC or DCPR8EIX as you earlier stated ( I got 40K miles out of a set of these).
Twin cam 10mm 2010 on MAR8B-JDS only seem to last 12K miles.

I would buy NOTHING used from Lituania. I have been watching used spares on Ebay for years now and its funny how the breakers in Lithuania had plenty of used R1200GS UK pattern headlights amongst hordes of other spares at a time when bike crime is rife: In my view these are most likely stolen UK bikes broken up and sold on ebay and you could be both fuelling the demand for bike crime and telling the criminals where to steal their next bike from by providing your postal address. I could be wrong about this of course and perhaps this is a legitimate bike breaking business that regularly buys up UK bikes in volume.

Pukmeister said:

I would buy NOTHING used from Lituania. I have been watching used spares on Ebay for years now and its funny how the breakers in Lithuania had plenty of used R1200GS UK pattern headlights amongst hordes of other spares at a time when bike crime is rife: In my view these are most likely stolen UK bikes broken up and sold on ebay and you could be both fuelling the demand for bike crime and telling the criminals where to steal their next bike from by providing your postal address. I could be wrong about this of course and perhaps this is a legitimate bike breaking business that regularly buys up UK bikes in volume.

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You're not the only one thinking exactly this...

To be fair, we have plenty of or own home grown scroats as well. Found loads of pieces of my stolen GS (few years ago now) on an Ebay breakers in Luton. Told the police and insurance co.

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Slipperyeel said:

You're not the only one thinking exactly this...

To be fair, we have plenty of or own home grown scroats as well. Found loads of pieces of my stolen GS (few years ago now) on an Ebay breakers in Luton. Told the police and insurance co.

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.....and let me guess the outcome. Quick as a flash, fuck all happened ??

Are the coils the same for the Single and Twin cam models ? There seems to be a myriad of different part numbers on RealOEM ?

I just put beru whatever part numbers ending 383 (left lower), 384 (right lower) and the two main ones 385

I believe 385 would be for both models
But the lower ones on the earlier bike are slightly different, the later ones will fit but the angle from the ninety degree plug cap to the electrical connector of the 383 and 384 is much closer to a 90 degrees offset, whereas the stock old bike is only about 15 degrees, so the loom only just reaches (you may have to untangle / reroute to do it nicely), and the cap is also about 5mm longer. Together the plastic covers are now quite snug. I wonder long term if the cover running so close/ touching will transfer engine vibration and cause them to fail slightly early. Lower ones also have an extra cable route bit that does nothing you should probably cut off for the older bikes. I was lazy seeing if they'd actually fit and left it there, it too makes the cover harder to fit

The main coils you need to transfer the rubbers off the old one (dust / water shield - the main ones come with nothing at the electrical connection end)
And for the older bikes the rubbers on the old one are a more suitable shape

Plug change intervals

I agree with the point about the colour of the plugs, my 12 plate is just the same and has been since new. Interestingly enough, one of the BMW service technicians once told me, when I asked about this very thing, that the secondary plugs do very little and in fact probably don't need replacing as often as the primaries.
He suggested only swapping the primaries every time and the secondaries every other change. Better than binning secondary plugs after a single service interval as you would a primary.