Can anyone take a look at my spark plugs?

Crab_Cake

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These guys have been going for a few thousand miles on mixed driving. I have my bikes carbs tuned pretty rich.

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They look pretty good to me, can't fault them myself.. I was always told you want them not too black and not too white/grey, and they need to be dry not oily, and preferably tan in appearance.

I.
 
In a perfect world they would be closer to tan but with mixed driving and the possibility of overheating an engine I'll take dry and black after several thousand miles over the alternative. Looks like it's just time for new plugs.

And don't forget the gap gauge as plugs haven't been gapped from the plug factory since the early 1970s.
 
I've never seen plugs that used up before.


P.S. Here's the method of reading plugs, as far as I'm concerned.
 
When was it shut down? Are we looking at idling plugs, plugs throttle chopped at 4K rpm,
or a redline throttle chop.

They will change. It would seem to me you would want to see what they are doing at the RPM you ride at mostly.
 
Crab Cake, it's impossible to get meaningful information from plugs that have seen mixed use. The starter system (choke) on these machines is pretty aggressive, and if those plugs were pulled after a cold start followed by some short hops, you could expect them to look that way. If that's how they look after 10 or 15 miles of mixed town and highway miles, however, you're running rich as Gates somewhere. The idea that a fat mixture is good for the motor is a fallacy. Carbon is highly abrasive and does the motor no good when it builds up and flakes off, and enough carbon buildup can create issues with detonation.

Re. plug reading: see Gordon Jennings' classic article on the subject at www.strappe.com .
 
And I thought those fancy expensive plugs were supposed to burn cleaner, lol. Guess I'll stick with the $2 standard version and I prefer it burn a bit cleaner like so .....

PlugColor.jpg
 
I can understand the L & R. But why did you mark/index them? Do you also mark the head?
 
I mark the open end of the electrode for indexing purposes. For a better burn, it's best to have the open end towards the intake valve so the spark is not masked, or at the very least not have the side that's welded to the plug top facing that way. To get it perfect, you would need to use indexing washers, which I don't. In reality, as long as the closed side isn't in the 12 to 3 (left cyl.) or 9 to 12 (right cyl.) area, I'm happy :).
 
Tan is good, but always better to run a little rich than too lean. As long as they're not "white hot". I agree with Weekendrider, how long did the bike idle before you shut it down and pulled the plugs? Carbon will build up if you let it idle and then try to rad the plugs. As long as its running good, don't fix it if it ain't broke. Don't ask me how I know this!:)
 
The connection of the line to the opening went right over my head.
Couldn't see the tree for the forest.

5twins I'll never be able to repay you for the schoolin.
so...

Thanks!!!!
 
Posted something very similar here a while ago. Here was John's easy tip for looking at your spark plugs:

If it's not the dirty carbs then it's easy to set the larger pilots too rich..........best way I have found to set them is to warm the engine to operating temp (say after 10 miles or so) the run along at low throttle (30-40 mph) and check for soot on the plug rung........just a "very" faint trace is good...setting each side individually....heavy trace is too rich and none may be lean.........here is a pic that may help..........and the wiring harness needs to be cleaned well and especially the large multi plugs that work the ignition......I have had to clean mine twice in 78 thousand with problems resembling yours.......don't forget the 2 wires at the coil..........hope this helps....

Edit.........forgot to mention.........with the larger pilots you need to do the final set in warm weather like 80 degrees and above since it will be much richer then.......and this setting should be fine for the winter ................

xsjohn

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If you don't know for sure, I would spend a day playing around for the right mixture. (For the love of god bring gloves, these suckers are really hot when you're checking them fresh. Also, bring that nice screwdriver you have for the soft brass adjustment knobs on the carburetors.)
 
I also use John's "soot ring rule". The video linked to above is a bit misleading in that I think it pertains to new completely clean plugs. Any plug that's been in service for a while is going to blacken that outer ring. The trick is to tune so that black doesn't rub off on your finger like in John's pic.
 
http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html

Most of you have probably seen this link..........it gives some good pictures.

Here's a pic of my plugs.................good old NGK BP7ES............perhaps a little on the lean side but work well for me. I get about 56 mpg on the highway.

Crab Cake.............you may have oil being sucked in via the head gasket from the cam chain tunnel.
 

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