FHP plugs

I've been messing around with different plugs for years now and wondered if anyone had any recommendations?

It's a 96" flatheadpower knuckle from 2003



Would appreciate your comments

Thanks

Griff

nice looking bike!

what have you tried so far? i have pretty good luck with NGK in my pan and in a buddies knuck. champions work well too.

i do know resistor plugs do not work well for me.

john

Thanks John, is that an FHP knuck if so which model of plug?

Thanks

Griff

nope regular knuck, what size does a new one take? 18 mm?

john

H-D # 3's.

Beware of modern NGK A6 plugs that are now resistors, but not labeled as such.
Dixie recently still had old stock.

Once upon a time a fellow posted to this forum, I believe, that he cut his plugs open and found algae.

Is he still with us?


....Cotten

I'm currently using an Accel 116

I found this great cross reference chart so it seems the same as a BP5ES

http://www.angelfire.com/extreme4/skido ... ERENCE.htm

Griff

I use C 86 in AC or 386 in Autolite.

Jerry

I ask this same question after finishing my fhp top end have been running ngk B7ES after the help of our friends on this site

live to ride tshoe

Thanks Tshoe

The B7ES is much shorter than the ones I've been, using Accel 116 (ZGR5C or BP5ES equavalent depending on which site you believe)

http://www.sparkplugs.co.uk/pages/datab ... artno=B7ES

http://www.sparkplugs.co.uk/pages/datab ... rtno=ZGR5C

I'll give these a go and let you know.

Thanks

Griff

Be careful when buying plugs based on the H-D number - that's a heat range and service recco, and does not specify which engine. There's also a #3 in 14mm for panhead etc.

The B7ES is much shorter than the ones I've been, using Accel 116 (ZGR5C or BP5ES equavalent depending on which site you believe)

The B7ES and BP5ES is basicly the same. The main difference is tha the center electrode is produding longer in to the chamber on BP-plugs. ZGRR5C is different.

http://www.sparkplugs.co.uk/pages/datab ... rtno=BP5ES

IMHO the extended tip (NGK "P") is preferable, and will run slightly cooler as the tip is in the intake wash. However, it must clear the piston dome not only with safety, but with enough room for the flame kernel to expand away from the gap without obstruction.

I use C 86 in AC or 386 in Autolite.

Jerry

Autolite 386 is a resistor plug. Autolite 3116 is the non-resistor version. And that's the one I've been seeming to have luck with.

Try the Bosch quad platinum 4479. They are 14mm, long reach with a very broad heat range. I've been running them in my '40 knuck on the street for about 5 years and never fouled one. Thats saying something for a stroked knuck.