Read these plugs?
#21
10-21-2010, 09:34 PM
One size bigger jet on my 99 EVO stopped the popping on decel, and also the occasional miss fire. Plugs still look good, just a little more tan than all white. It will now run after a short warm up without the enrichner on. I pull the enrichner to start it, then push it in when running, and hold a good idle with the thumbscrew lock on the throttle. Driveability is much better, and it pulls better at low rpm.
#26
10-21-2010, 11:14 PM
Seasoned HDF Member
Lean
Way lean, Looks like you have been using them or it to carbon arc in aluminum. Just kidding. They look just like the ones I just took out of my FI motor witk 40K. They had about 9K on them. They would probably go another 30K. Do not believe I can focus in that close with my camera. One on right appears to be bridged but its not.
Last edited by Jackie Paper; 10-21-2010 at 11:32 PM.
#27
10-22-2010, 12:20 AM
Stellar HDF Member
They look like you're running a bit on the lean side and/or a plug heat range one range to hot. The little speckles on the plugs are splash deposits that have been glazed due to high heat. Ideally the color of the ceramic should be a slight shade more gray and without the little speckles that you see on these plugs. This picture is of a Spark Plug that has suffered from pre-ignition and is a severe example of this type of failure but if you look at the ceramic you can see the similarity to your plugs.
Last edited by Bluehighways; 10-27-2010 at 11:04 PM.
#28
10-22-2010, 03:26 AM
Hmmm, this is interesting, It's been a while since I jetted a carb and I have a great Euro lager in front of me right now...but...I've always jetted off of performance rather than plug color, I've read so much crap on plugs I decided that the performance route was the best way. Some people turn this into an actual science, some say that you can't read a plug properly unless you do specific things first like throttle chops, or turn it down on a lathe...yada, yada...
Anyhow, after a 30 mile run, I'd think that the mains were lean. The reason I say this is that the pilot only really supplies fuel till what, about an 1/8 throttle or so? It's all main from there right? However, I guess it would depend on when the carb farts are happening, at idle, at cruise, while rolling off the throttle...If the bike performs well out of the pocket/pulls hard from a dead stop...I'd tend to think that the pilots were ok since it's not running away (lean), or falling it's face (fat)...just putting it out there to see where this goes...
Anyhow, after a 30 mile run, I'd think that the mains were lean. The reason I say this is that the pilot only really supplies fuel till what, about an 1/8 throttle or so? It's all main from there right? However, I guess it would depend on when the carb farts are happening, at idle, at cruise, while rolling off the throttle...If the bike performs well out of the pocket/pulls hard from a dead stop...I'd tend to think that the pilots were ok since it's not running away (lean), or falling it's face (fat)...just putting it out there to see where this goes...
#29
10-22-2010, 03:45 AM
Cruiser
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They look great, the base ring should look like chocolate milk, watch this video. http://www.youtube.com/watch?v=fiMM2S0aADM Most people read plugs wrong. (Not any of you guys of course) The ring around the base is where you look at jetting and nowhere else, not the ground strap or the porcelin, they indicate heat range and detonation respectively.
#30
10-22-2010, 05:39 AM
I've re-jetted the carb but, as I understand it, the only real way to tell if the bike is running rich/lean/correctly is to interrogate the plugs. I do get some popping on decel but the bike seems to run strong. It pulls hard and sounds great, albeit with a very occasional carb fart.