Plug Readings
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Road Warrior
Joined: Jan 2007
Posts: 1,276
Likes: 8
From: Minneapolis Area, MN
Plug Readings
Hey guys...
What would be some causes for the plugs in the pic below?
The plug toward the front (right) came out of the front cylinder and the plug toward the back (left) came out of the rear cylinder.
My guesses would be a rich engine with an intake leak on the front cylinder, or maybe a proplerly tuned engine with a weak spark on the rear cylinder? Maybe a failing ignition or coil or plug wires?
Any thoughts?
[IMG]local://upfiles/23327/B5F31165BA874DB6895BF697CDCB3705.jpg[/IMG]
What would be some causes for the plugs in the pic below?
The plug toward the front (right) came out of the front cylinder and the plug toward the back (left) came out of the rear cylinder.
My guesses would be a rich engine with an intake leak on the front cylinder, or maybe a proplerly tuned engine with a weak spark on the rear cylinder? Maybe a failing ignition or coil or plug wires?
Any thoughts?
[IMG]local://upfiles/23327/B5F31165BA874DB6895BF697CDCB3705.jpg[/IMG]
Road Warrior
Joined: Jan 2006
Posts: 1,792
Likes: 1,186
RE: Plug Readings
I have seen many, many HD plugs where the rear is much darker than the front. I never considered it much cause for concern, but if you have a PCIII where you can adjust fueling to the indvidual cylinders, you could probably address it that way. You might also try running a hotter plug in back.
The best indicator or the correct A/F mix that I've found is the coloring of the ground strap. Ideally, it should be light from the tip to the 90 degree bend, and then become dark. It's difficult to see in your pic, but remember also, that's just an ideal.
Uncle Peepers
The best indicator or the correct A/F mix that I've found is the coloring of the ground strap. Ideally, it should be light from the tip to the 90 degree bend, and then become dark. It's difficult to see in your pic, but remember also, that's just an ideal.
Uncle Peepers
Road Warrior
Joined: Feb 2005
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From:
RE: Plug Readings
Just wondering what year's your bike - you know the 2005's have a valve seal recall which-are you using any oil? If the engine isn't warming up properly, that might do it too - pretty hard to warm up an HD this time of year - might take 30 miles according to the techs. A little more info will be helpful.
Advanced
Joined: Oct 2006
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From:
RE: Plug Readings
To get a good plug reading, you need to run a while at your normal road speed, shut the engine off and coast to a stop; then check the plugs. Careful, they are hot! Idling and low speed operation won't provide a good fuel-air mixture.
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From: Nevada
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Road Warrior
Joined: Jan 2007
Posts: 1,276
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From: Minneapolis Area, MN
RE: Plug Readings
Uncle Peepers
...if you have a PCIII where you can adjust fueling to the indvidual cylinders...
...if you have a PCIII where you can adjust fueling to the indvidual cylinders...
*****
Retired_Ted
Just wondering what year's your bike...
Just wondering what year's your bike...
*****
67xlch
To get a good plug reading, you need to run a while at your normal road speed, shut the engine off and coast to a stop...
To get a good plug reading, you need to run a while at your normal road speed, shut the engine off and coast to a stop...
*****
nvsteve
I'd be concerned with the front plug as well.
I'd be concerned with the front plug as well.
*****
Anyone else willing to pull their plugs as they sit for a comparison?
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Road Master
Joined: Jul 2005
Posts: 1,043
Likes: 4
From: New Mexico
RE: Plug Readings
Depending on the miles you have on the plugs the back one looks ok the front rich. Pc 3 will take care of that rich plug. If you had intake leak, it would be poping on decel. Try the stock plug.
[IMG]local://upfiles/3159/6067F44480FF4B8BBD9D28F2864A1341.jpg[/IMG]
[IMG]local://upfiles/3159/6067F44480FF4B8BBD9D28F2864A1341.jpg[/IMG]
Ultimate HDF Member
Joined: Nov 2005
Posts: 5,256
Likes: 5
From: Concord, CA
RE: Plug Readings
I'll throw in my 2 cents...
See how worn the electrodes are... How old are these plugs?
With the electrodes worn like that, you aren't getting optimal fire no matter what.
Being that it's a 98 wide-glide, I doubt that its fuel injected. Could be wrong... So a PCIII won't help there.
Cylinders do run quite differently from eachother on a HD as I recently (today) found out.
Since the bike has been sitting, then started and not really run, and probably had the enrichener on for a bit, I would re-evaluate after actually getting to go out and ride and of course using new plugs.
See how worn the electrodes are... How old are these plugs?
With the electrodes worn like that, you aren't getting optimal fire no matter what.
Being that it's a 98 wide-glide, I doubt that its fuel injected. Could be wrong... So a PCIII won't help there.
Cylinders do run quite differently from eachother on a HD as I recently (today) found out.
Since the bike has been sitting, then started and not really run, and probably had the enrichener on for a bit, I would re-evaluate after actually getting to go out and ride and of course using new plugs.