Spark plugs

[RibEye]

Re: spark plug poll

And the Ion Sensor needs to work properly so why take the risk of running anything but the right plug.. Take 1 look at some of these spark advance numbers from a stock factory map from my 2009. (If it displays correctly) the left column is RPM top to bottom and "engine load" is from left to right with far right being WOT.

Look at all the high 30's and 40's of degrees of advance.Your engine could never live a long life without some sort of spark retard kicking in when you quickly twisted the grip from a light load map in the 3000 RPM range.


Harley Davidson Community

Wow. That does seem to be alot of advance there. It leads me to believe that what I am hearing when I roll on from low rpm is not ping but knock. That is a different sort of animal indeed...one with big teeth.

Enjoy,
Rich P

 

[Hoople]

Re: spark plug poll

Wow. That does seem to be alot of advance there. It leads me to believe that what I am hearing when I roll on from low rpm is not ping but knock. That is a different sort of animal indeed...one with big teeth.

Enjoy,
Rich P

Oh that is not just a lot of advance,, it's more than any engine could possibly handle under a load. It is done to squeeze every drop of mileage out of a gallon of gas and also to reduce emissions. You can get away with it as long as your Ion Sensor is working properly, and you don't whack the throttle hard but instead give the map sensor a chance to respond and send the info to the ECM.

I immediately knew something was up when my bike was brand new. From a nice low load cruise speed if I twisted the throttle quickly to WOT, I would hear 2-3 hits of detonation until the entire system had time to react and correct for it. I have since re-mapped both spark advance curves to something more realistic.

 

[nvsteve]

Re: spark plug poll

It would not matter if you were touching the ground strap at the same time.
It should be a straight forward reading.

When you say the readings are not consistent, what do you mean. If may drift a decimal point or 2 but that should not matter. The fact its happening on several plugs tells me it's either the range the meter is on or it's a problem with the meter itself. What type of meter is it.

The meter is a Fluke.
I just checked a handful of plugs touching both the strap and center electrode. Easier that way. All plugs were lightly used except the
Champion 6's.
These are approx. avg. readings:

HD 6R12 16K
NGK DCPR7 6K
Autolite 4164 6K
Champ RA8HC 75K (yes, 75K)
Champ RA6HC No reading. Interesting, these are new one step colder plugs.

 

[ultrat]

Re: spark plug poll

checked some plugs too denso w16ekr-s11 no reading ? new just pulled some out of my bushel basket..

 

[Hoople]

Re: spark plug poll

The meter is a Fluke.
I just checked a handful of plugs touching both the strap and center electrode. Easier that way. All plugs were lightly used except the
Champion 6's.
These are approx. avg. readings:

HD 6R12 16K
NGK DCPR7 6K
Autolite 4164 6K
Champ RA8HC 75K (yes, 75K)
Champ RA6HC No reading. Interesting, these are new one step colder plugs.

75K. Wow. That is incredible. Would you know off hand what that plug was used for? The 16K & 6K are what I would expect. Those are realistic numbers. But the 75K is wild.

 

[Hoople]

Re: spark plug poll

checked some plugs too denso w16ekr-s11 no reading ? new just pulled some out of my bushel basket..

Some plugs actually have a very small internal gap inside the porcelain insulator. The gap is there to help fire a plug that may be fouled. That is what you may have there.
So if you checked them with a meter you would get a reading of infinity.

 

[Hoople]

Re: spark plug poll

The meter is a Fluke.
I just checked a handful of plugs touching both the strap and center electrode. Easier that way. All plugs were lightly used except the
Champion 6's.
These are approx. avg. readings:

HD 6R12 16K
NGK DCPR7 6K
Autolite 4164 6K
Champ RA8HC 75K (yes, 75K)
Champ RA6HC No reading. Interesting, these are new one step colder plugs.

Wait a minute. You said a HD 6R12 is 16K. I read much higher on 4 new plugs.
Let me double check my meter and do it again.

 

[nvsteve]

75K. Wow. That is incredible. Would you know off hand what that plug was used for? The 16K & 6K are what I would expect. Those are realistic numbers. But the 75K is wild.

Yup, they are the stock 6R12 cross over. Probably have less than 5K miles on them.

Wait a minute. You said a HD 6R12 is 16K. I read much higher on 4 new plugs.
Let me double check my meter and do it again.

Yes, they are lightly used and I did several of them a couple times each.

 

[Hoople]

Just checked two New in box plugs (HD 6R12) with a different fluke altogether.
One reads 31.5K and other 34.7K. So much for quality control. But it does not surprise me coming from Champion.

I can't explain why your getting only 16K. A used plug should even read higher. Strange indeed and something I need to research.

 

[Hoople]

Re: spark plug poll

Yup, they are the stock 6R12 cross over. Probably have less than 5K miles on them.

What do you mean when you say "stock cross over"? Are you saying they are not Genuine HD but are a different brand crossed over to the original?