plug failure

A plug failure is hard to comprehend. And I do not think that the fact that you have an electronic system will effect a failure.

Other than a plug failure caused by a buildup of carbon/oil, the only other way I can imagine a plug failure (and I am talking here about a mechanical failure) is if the part that arches over to above the central point had broken off or burned off.  Other than that the only other way a plug can fail is if it gets so full of carbon/oil that a path is created such that the spark from the central electrode takes a short-cut (heh-heh)( no pun intended).  It is possible, I guess, that the central core could get broken but that would be a very unusual circumstance.

Anybody else have any ideas?

Mike

Many, many, years ago I had a duff plug on a Honda 250 twin. The reason, cracked ceramic. One pot would fail intermittently especially if the weather was damp, (strangely everything was fine in proper rain). Once I was on my rest days I swapped the plugs for new ones, problem solved. It was only when I had a really close look that I found a crack running down the ceramic section. Since then I always have spare plugs on me when I'm out for a run, cleaned and gapped ready to fit.

John

Many years ago  I did servicing to earn some pocket money. I used to buy Champion Plugs in boxes of 10. Before installing I used to test the plugs for internal continuity. I regularly threw 2 out of 10 away.  I never had plug problems.   The new Champion plug in my new lawnmower was dead and close inspection revealed a shiny metal bridge between the earth electrode and the center.   Standards appear to be slipping----------.

Apparently there are a lot of fake NGKs about: http://www.ngk-sparkplugs.jp/english/techinfo/fake/index.html

Also, the ceramic nose of modern plugs is not glazed as they used to be in the GODs. This means that once fouled they're very difficult to clean.

I race two strokes and can assure you that plugs fail and often for no reason visible to my eyes! I put in a new plug and off I go. Some last all season some only a meeting,  go figure!

In my youth I had a CR125, that would eat a champion plug in about half an hour, NGK lasted much longer.

dan

You must be a very lucky man. Probably never had a 2-stroke. The modern bike I have shall have plugs changed every 7600 miles. So Kawasaki thinks that hopefully plugs last some 10,000 miles. My experience is that most plugs don't fail even after 4 times of that mileage. Exception was the race plugs in JAP and JAWA speedway engines. They consumed plugs at an amazing rate.

Anyone tried the above? They are advertised as being particularly suitable for older engines.

Iridium tipped plugs - worth the extra expense?

best regards,

Chas

Many years ago I had a TD1C Yamaha which refused to run on anything but Lodge RL50s/ 51s! Nowadays, after a lot of trial and error, I've settled on Denso IW22s for my 650SS and Clubman Venom. Highly recommended.

As said, lots of fakes. But even if made by NGK there is said that those made in Japan is better for my Manx than those made in their French factory.

Electronic ignition should not bear on plug failure, BUT as the two sparks on (Parallel twins) are together with wasted spark then swapping the plug leads over will move the spark. If the fault persists on the same cylinder then it is carburation, or valves or such on that cylinder. If the problem moves then the coil is suspect and its connections. If a coil is reversed connected it will work but not as well as if it was correctly connected, ie an apparent plug failure could be due to lower output from the wrongly connected coil. At the same time do NOT trust a couple coils of different parentage or age. It is even possible that the weaker plug is being supplied by better coil as the other coil is robbing the first plug/coil. If in doubt change both coils.