Board index Flathead Power-Technical Questions, Answers, and Suggestions Knuckles FHP plugs

FHP plugs

Moderators: Curt!, Pa

Post Sun Jan 17, 2010 5:47 am

Posts: 18
Location: Cambridgeshire, UK

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

Image

Would appreciate your comments

Thanks

Griff

Post Sun Jan 17, 2010 10:38 am

Posts: 377
Location: madison wisconsin usa
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

Post Sun Jan 17, 2010 1:07 pm

Posts: 18
Location: Cambridgeshire, UK

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

Thanks

Griff

Post Sun Jan 17, 2010 9:54 pm

Posts: 377
Location: madison wisconsin usa
nope regular knuck, what size does a new one take? 18 mm?

john

Post Mon Jan 18, 2010 12:44 am

Posts: 2684
Location: Los Angeles, CA
H-D # 3's. :D

Post Mon Jan 18, 2010 11:25 am

Posts: 3061
Location: Central Illinois, USA
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

Post Mon Jan 18, 2010 1:38 pm

Posts: 18
Location: Cambridgeshire, UK

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

Post Mon Jan 18, 2010 10:32 pm

Posts: 607
Location: Menomonie, Wisconsin, USA
I use C 86 in AC or 386 in Autolite.

Jerry

Post Thu Jan 21, 2010 10:51 pm

Posts: 77
Location: Custer Wa.
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

Post Fri Jan 22, 2010 3:31 am

Posts: 18
Location: Cambridgeshire, UK

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

Post Fri Jan 22, 2010 9:04 am
panic

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.

Post Sat Jan 23, 2010 2:14 am

Posts: 90
Location: Norway
Griff wrote:
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
Torstein

Post Sat Jan 23, 2010 7:40 am
panic

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.

Post Mon Jan 25, 2010 1:01 pm

Posts: 172
Location: San Diego, CA
Jerry Wieland wrote:
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. :wink:

Post Thu Mar 25, 2010 9:53 pm

Posts: 33
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.


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