I replaced my spark plugs a few weeks ago with NGK plugs. Today a BMW mechanic whom I have trusted in the past told me to switch to Bosch. Apparently there is a contact problem between the plug and the boot with the NGK plugs. Do any of you have an opinion on this matter?

Thanks
Ralph

I fail to see this... NGKs are universally used as are Bosch on all manner of new and old vehicles. I've used both on Ks and other bikes...without problems.

Although the plugs are important there are, IMHO, just three things that I would be concerned about:
a. replace normal plugs with the resistive type (potential ignition coil problems),
b. change heat range (run too hot or cold) and
b. replace the normal plug with a platinum type (better spark and plug life).

These three things are the only things I would be concerned about and have a real performance effect. German, Japanese, American.... they all work just the same.

I am running with NGKs for year and never experienced any problems.
Your mechanics may have had previous problem with NGKs, and I will not put him down for this remark. The fact is that apparently Bosch stopped manufacturing the spark plugs for our bikes and we may have to switch to NGK or Champion.

I am currently using NGK's, resistor type , and I have no problems.

Rick

NGK, the original copper core since 1958! I've used and sold them since the late '70s with only one ever failing on a personal vehicle of mine in that time. I use DR7EA in my K100RS. I have no problem with Bosch plugs either. I think you will not notice any difference using either brand, though availability might be an issue with Bosch.

I use ngk's and have no probs at all, i do also have the ngk plug leads fitted too.

I think the comment might be because NGK plugs are not normally delivered with the screw-on bobbins that the K plugs need. The Bosch are fitted with them originally.

I agree with all the above, I have used NGK's in many bikes and cars all with perfect results. The quality is excellent and Rene's comment is spot on but once you have a set of bobbins that is no problem. I also have found that Iridium plugs are excellent improving spark efficiency and life but at a purchase cost. The resistor/no resistor issue depends on the year, earlier K's used non resistor plugs and had the resistance in the cap, whereas the later ones used resistor plugs and no cap resistance. The exception to that was the K75 which had a spark gap in the lead.
Regards,
K-BIKE

Was clearing out the top shelf of my top tool box in the garage today and discovered about twenty of those requisite Bosch to NGK conversion spark plug bobbins if anyone needs any... Gimme your address and I'll post 'em to you, gratis.

Hey TWB,

Do you still have any of those conversion bobbins around the garage?
Looks like I'm going to need some...


OG

Hi og. I got some from the local lawnmower repair shop. They took them from old plugs that they had binned. FREE!

Nice! Yeah, I'm going to try and score some freebies somewhere...