Spark Plugs

[Grant Freeman]

#2849

Hi,Whilst trying to track down my intermittant ignition problem I started with the easy stuff and checked the spark plugs, HT leads etc and to my great surprise, found that the spark plugs were NGK BCPR7ET with three electrode earths. The plugs as per the manual are Bosch FR6 DDC and whilst I could not get these for love nor money, I got the NGK equivalents BKR7EKC-N which have two electrode earth points.The bike has been serviced from new at Bay motorcycles and I assume the NGK plugs were fitted there, but now that I have changed them to the equivalent spec plug, the bike starts easier, performance is better and it even sounds better.It did not cure my intermittant problem however, as I went for a ride and it cut out twice, but then provided me with another 120 Kms of trouble free riding? I dont know what the NGK BCPR7ET are equivalent to, but I had a look down the plug hole of each cylinder with a small scope and the piston crowns are OK, so I assume that they are a softer plug than the spec plug?Cheers,Mike  

[Grant Freeman]

#11562

Hi,I checked up the specification of the BCPR7ET plug against the BKR7EKC-N plug and the oly difference is the number of earth electrodes - the number 7 is indicative of the heat rating of the plug.http://www.cyclechaos.comGood web site. I just wonder why the three eartch electrode plugs were fitted over the two earth electrode plugs by I assume a BMW dealer?Bike runs better with the two earth electrode plugs in anyway.Cheers

[David]

#11563

The NGK BKR7EKC-N plug nose is 2mm longer than the OEM Bosch FR6 DDC plug and therefore is firing in a different position in the combustion chamber. I was surprised when I changed the plugs and this produced an apparent increase in engine performance. 31000km later and no apparent problems. The OEM Bosch plugs are available from Experience BMW at a reasonable price.Link to NGK's part number explanation page: http://www.ngksparkplugs.com/docs/tech/partnumberkey.pdfMy bike used to cut out intermittently until I found I had damaged one of the ignition circuit wires when I fitted a Kissan Signal Minder. Now repaired it hasnt missed a beat since.

[Grant Freeman]

#11564

Hi DickT,Thanks for your advise. I assume you have the Bosch plugs fitted rather than the NGK BKR7EKC-N plugs then? I shall have to try the Bosch plugs, but could not get any locally (hamilton) I have just spent the day on my bike in search of my intermittant problem and seem to have cleared it now and just came back from a test ride and the perofmance of the bike is much better and revs easier, and that is with my NGK plugs inI have also been reading BMW - The racing story (mick walker) and it mentions in there for the R259 engine that three earth electrode plugs are standard for the engine, so is the Bosch plug a three earth electrode or two earth electrode, as the BKR7EKC-N is the NGK equivalent for the Bosch FR6 DDC plug and when they say "equivalent", I assumed the number of earth electrodes to be the same?CheersMike.   

[Author]

Posts