Hottest plugs?

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Jul 24, 2017 | 11:31 PM

#11

TriGeezer

Seasoned HDF Member

Joined: May 2012

Posts: 32,934

Likes: 36,031

From: Carlsbad, CA

Quote:

Originally Posted by 0ldhippie

Most higher compression performance engines actually require cooler plugs not hotter ones...and higher octane fuel burns slower, not faster...

Yup...therefore..."hot plugs" can cause predetonation..a.k.a. Pinging ...

...

Jul 25, 2017 | 12:15 AM

#12

dickey

Seasoned HDF Member

Joined: Mar 2010

Posts: 19,980

Likes: 6,108

From: Florida

Hotter than standard plugs were OK back in the carb days when it was running rich, but I'd stick with stock.

Jul 25, 2017 | 05:57 AM

#13

Bubba Zanetti

Seasoned HDF Member

Joined: Nov 2006

Posts: 21,053

Likes: 19,189

From: The Wasteland

Jesus! Someone answer him before he starts another thread about hot plugs, this is the third one already...

Jul 25, 2017 | 06:05 AM

#14

Dennis Lett

Cruiser

Joined: Jun 2017

Posts: 135

Likes: 12

From: Omaha

Quote:

Originally Posted by dickey

Hotter than standard plugs were OK back in the carb days when it was running rich, but I'd stick with stock.

Hotter plugs weren't really for when it was running rich, but carbon tracking. Some used them for the hard to "tune" butterfly carbs, but they were mainly just looking for a more complete burn. I've used a step hotter for that purpose and a step colder if she pings, but only on a carbed bike.

How hot a plug is would be determined by how much of the insulator is exposed. It's the plugs ability to shed the heart of combusting combustion. Too cold, it won't be able to burn off excess carbon, too hot, you'll get spark knock or pinching.

Hotter or colder plugs not needed on FI bikes because of knock sensors, injector timing and other various sensors bound and determined to make your bike run smoothly.

Jul 25, 2017 | 07:27 AM

#15

TheGrandPoohBah

Extreme HDF Member

Joined: Jun 2011

Posts: 14,731

Likes: 2,536

From: Mountain Top, Alabama

Let's not try to out engineer the engineers.
Run your plugs about 10,000 miles, pull 'em, look 'em over, and then lets continue this discussion.
There's plenty of other things to be concerned with. Run 'em!!

Jul 25, 2017 | 01:04 PM

#16

B Bop

Road Captain

Joined: Feb 2013

Posts: 651

Likes: 72

From: Harleysville, PA

As oldhippie said: Most higher compression performance engines actually require cooler plugs not hotter ones...and higher octane fuel burns slower, not faster...

Buuuuut they already knew that! Right?

B Bop

2012 FLHR (Road King) Ember Red Sunglo & Merlo
Cruise Control, ABS, Chrome Aluminum Profile Laced Spoke Tubeless Wheels, Security Package, Saddle Bag LED Lid Spoilers, and an array of accessories that enhances nostalgic appearance & blood curdling performance.

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Last edited by B Bop; Jul 25, 2017 at 01:07 PM.

Jul 25, 2017 | 07:14 PM

#17

btsom

Grand HDF Member

Joined: Jan 2012

Posts: 4,458

Likes: 2,880

From: Oklahoma

Perhaps the OP believes that a hotter plug delivers "hotter" performance (more power). The original question makes little sense otherwise.

Jul 25, 2017 | 09:46 PM

#18

Veekness

Elite HDF Member

Joined: Nov 2013

Posts: 4,377

Likes: 647

From: Santa Clarita

Quote:

Originally Posted by btsom

Perhaps the OP believes that a hotter plug delivers "hotter" performance (more power). The original question makes little sense otherwise.

Yeah, I've come to believe that you are exactly correct on that...

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Jul 27, 2017 | 10:33 AM

#19

longrideshields-2

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Joined: Jul 2009

Posts: 967

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From: Reno, NV

I have tried them all, Bosch are the best. And yes, cross the same OEM # over. Using hotter plugs is for Shovels and Pans. Also with F I System, there is not the same issues as with the carburetor bikes... https://www.boschautoparts.com/en/auto/spark-plugs

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