Spark Plug Choice and Gap

spub · Post by **spub** » 12 Oct 2009 15:44

I have read the 3 1/2 Service Manual and the Manual for the 125-500 models, and other sources and have received conflicting information on the choice of plugs and the gap value. Most books say B7 NGK, others say this is too cold and B6 plug is required.

I have read recommended values ranging from .5 to .7 to .9mm, depending on the source. My experience with the Ducati Electronica ignition would lead me to go with .7, but that is quite a range.

What is the recommendation here?

Thanks.

gÃ¼nni · Post by **gÃ¼nni** » 12 Oct 2009 16:47

i use the platin-version of the BP7ES , the BP7EVX, with very good results.
much better in cold-start and lower idle speed if the 3 1/2 is warm .
iridium-version isn`t so good , because that is a resistor type and kills ignition-energy.
i think there is no need to use B6 spark plugs

cheers
gunar

EVguru · Post by **EVguru** » 13 Oct 2009 08:49

Plain old BP7ES work just fine for me.

BP7EV have the 'wire' centre electrode and help with a slightly weak spark, but wear faster.

The exotic materials simply allow a small diameter electrode to last.

If you don't put many miles a year on the bike, save your money.

I'd suggest that if you're fouling grade 7 plugs, then you have an underlying problem with mixture or worn bores/rings.