BMW K bikes (Bricks)

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Bonzo

Bonzo
Life time member
Life time member
I confess I've always used the slightest amount of copper grease when popping the plugs back in, but it seems there's conflicting practices. F'rinstance NGK recommend inserting the plug dry.

What's your take?



Last edited by Bonzo on Thu Mar 04, 2021 4:30 pm; edited 1 time in total


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1990 K100RS 4V (VIN# 6406682)
2017 R1200RS SE Sport
    

stanthomas

stanthomas
Silver member
Silver member
I use a wipe of copper grease. My thinking being it reduces wear on the threads - a consideration on 40 year-old engines.


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K100RS 16V '91
    

Suzi Q

Suzi Q
Life time member
Life time member
Is their plug really 'dry' - or does it come from the factory with something on it?
Copaslip every time for me. Can't see how it can damage anything.


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Sometimes I'm not really Suzi Quatro.
    

Point-Seven-five

Point-Seven-five
Life time member
Life time member
I use anti-seize on my plugs, but use a lower torque(about 10-15%) to prevent over tightening because of the lubricated threads.


__________________________________________________
Present:
1994 K75RT
1991 K100RS
1988 K100RS SE

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

Point-Seven-five

Point-Seven-five
Life time member
Life time member
I think NGK plugs are nickel plated to prevent corrosion.  So unless you leave them in for 25 years and keep your bike outdoors near the ocean they figure they won't seize in the head.


__________________________________________________
Present:
1994 K75RT
1991 K100RS
1988 K100RS SE

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

Suzi Q

Suzi Q
Life time member
Life time member
"So unless you leave them in for 25 years and keep your bike outdoors near the ocean they figure they won't seize in the head."

Now come on, you know somebody will have done that with a K!


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Sometimes I'm not really Suzi Quatro.
    

Dai

Dai
Life time member
Life time member
IMO, not a good idea. I've seen copaslip burn on and make the plugs a real bastard to get out.


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1983 K100 upgraded to K100RS spec, 1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

MartinW

MartinW
Life time member
Life time member
I've always put them in dry. I had a talk to an engineer at the Trades Guild and he said dry and as per Dai could cause problem getting them out. 
Regards Martin.


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K75s Hybrid
    

BobT

BobT
Life time member
Life time member
Never had a seized spark plug and never used anything on any automotive plug thread.
In many aircraft piston engines they call for a heat transfer grease/compound on plugs, the same stuff as you get on computer CPU heatsinks. Cannot remember the details of the grease now.

    

Bonzo

Bonzo
Life time member
Life time member
That's settled then. Conflicting  (o)


__________________________________________________
1990 K100RS 4V (VIN# 6406682)
2017 R1200RS SE Sport
    

cycleman

cycleman
Silver member
Silver member
I'm in the dry camp when it comes to spark plugs. Anti seize or anything else added to the threads can affect the heat transfer and grounding from the plug to the head.

    

RicK G

RicK G
admin
admin
I have used antiseize always when an alloy head is concerned. Over the years I have had to fix quite a few alloy heads that have had damaged plug threads some due to cross threading but also due to the plug seizing in the thread after being left too long before being changed or checked.
I suppose it could have a small negative effect on heat transfer but I don't think it would have any negative effect on conductivity.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 2004 K1200GT 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki
    

Point-Seven-five

Point-Seven-five
Life time member
Life time member
The danger with lubricating the threads is that it makes it easier to overtighten the plug and strip the threads out of the head if you aren't careful. It's the reason I use a lower setting on my torque wrench when installing spark plugs.

As far as heat transfer, the spark plug has absolutely nothing to do with removing heat from the cylinder, the only purpose for the heat transfer is to be low enough to keep the plug tip hot enough to burn off any carbon deposits, but not so hot that the electrode melts. The most important factor in heat transfer is the ceramic insulator that surrounds the center electrode. That's the part that changes for different heat ranges. A film of copper(a very good heat conductor) a couple hundred thousandths of an inch(.00001") thick has virtually no effect on the heat transfer from the plug to the head.


__________________________________________________
Present:
1994 K75RT
1991 K100RS
1988 K100RS SE

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

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