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Discussion Starter #1 (Edited)
2 pics, one with added light.

Based on what you know about engines, how do you think this one is running?

These are the original factory NGK CR9EIA-9 Laser Iridums replaced with same at 7,509 miles
294259
294260
 

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In the light, they look fine. Expensive plug to change Q 8K miles?
 
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Check the gap on all the plugs, if they are all in the same ballpark then it all looks good to me. I'm usually having to change it every season after 5 or 6 track days or every 10,000 miles. Whichever comes first but this is for the OEM spark plugs from NGK.
 

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Discussion Starter #5
Check the gap on all the plugs, if they are all in the same ballpark then it all looks good to me. I'm usually having to change it every season after 5 or 6 track days or every 10,000 miles. Whichever comes first but this is for the OEM spark plugs from NGK.
The manual spec is 0.031-0.035 so I gapped the new ones at 0.033

The old ones (1-4) are 0.034 and 0.036 on the other three. I think the 0.036 is close enough to the ballpark considering they had 7500 miles on them. Mainly wondering if the insulator color indicates a lean AFR. I don't think they do because they have a good light-tan color vs a stark white but I'm not a very good mechanic either so put them up here. The photos make them appear a little more white than they look in natural light. I did replace with the OEM NGK's
 

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The plugs are clearly shinny/wet brown/black, which would suggest you have oil passing by valve guides or rings. When you rub them on your finger, what type of material comes off. Does it smear like wet oil or is it a dry powder?

If this bike came to me I would do either a compression test or leak down test or both. How many miles on the bike?
 

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Discussion Starter #8
The plugs are clearly shinny/wet brown/black, which would suggest you have oil passing by valve guides or rings. When you rub them on your finger, what type of material comes off. Does it smear like wet oil or is it a dry powder?

If this bike came to me I would do either a compression test or leak down test or both. How many miles on the bike?
It's more like a dry carbon, not wet, and it's only on the outer edge of the tip. The far right cylinder has more of it than the other three. Insulators are clean so I doubt it's leaking oil. Coloration on the threads doesn't wipe off but I hadn't tried to do any cleaning on them before the pictures were taken.

These are the original factory plugs, mileage was 7509 when they were taken out.
 
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The threads just look very wet or sticky. What bike is it? With such low mileage especially not abused there is no reason to suspect anything would be wrong.
 

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Discussion Starter #11
The threads just look very wet or sticky. What bike is it? With such low mileage especially not abused there is no reason to suspect anything would be wrong.
It's a 2018 GSX-R750 that hasn't had a single burnout on the tire but has been ridden in the upper RPM range several times. Mostly just commuting to & from work and weekend tooling around though.
 

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Discussion Starter #12
Look up Kevin Baxter on Youtube. He's a harley guy but his video on how to read plus is by far the best I've ever seen.
He goes into a lot more detail than I've ever seen & looks like great info, thanks for the tip.

 

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^^^ Being a HD owner, I've really come to like this guy. Not bought and paid for, articulate, and knows what he's doing.
 

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That is the first I've heard of reading the ground strap to give an indication of timing and gauging the color of the porcelain to indicate mixture at various throttle/power settings. Interesting.
 

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Discussion Starter #15
That is the first I've heard of reading the ground strap to give an indication of timing and gauging the color of the porcelain to indicate mixture at various throttle/power settings. Interesting.
When looking into tuning these GSX-R's a source I don't remember (just associated with Woolich Racing Tuned software users) highly recommended a guy named Tracy Martin and his book "How to Tune and Modify Motorcycle Engine Management Systems" for good information. The book has a section on tuning AFR's based only on the color of the porcelain on the plugs. It made several mentions of the importance of shutting off the engine without allowing it to go to idle and also of doing riding tests at 1/4, 1/2, 3,4 and full throttle then removing the plugs after each run to check the porcelain color and adjust fuel delivery accordingly. Although it has some good general info on how engines and O2 sensors work, the WRT Logbox & software are leaps & bounds better IMO.
 
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When looking into tuning these GSX-R's a source I don't remember (just associated with Woolich Racing Tuned software users) highly recommended a guy named Tracy Martin and his book "How to Tune and Modify Motorcycle Engine Management Systems" for good information. The book has a section on tuning AFR's based only on the color of the porcelain on the plugs. It made several mentions of the importance of shutting off the engine without allowing it to go to idle and also of doing riding tests at 1/4, 1/2, 3,4 and full throttle then removing the plugs after each run to check the porcelain color and adjust fuel delivery accordingly. Although it has some good general info on how engines and O2 sensors work, the WRT Logbox & software are leaps & bounds better IMO.

Us "old schoolers" call it "Plug Chops". Ya toss a plug wrench in your back pocket, and (on a warmed engine) rip it down the road wide open throttle. Just as you are releasing the throttle, pull in the clutch and kill the engine. Pull off to the side, and pull your plugs, and read them. Take it back to the garage, and adjust your main jet accordingly. Do the same for 1/2, and 1/4 throttle positions, for your needle height, and pilot circuit.

I suppose, you could do the same thing with software to tune the ECU using the same process. I would think it would at least get you pretty close. Still, the best way to tune any of them (especially injected engines) is on a Dyno. We all don't have that luxury, and do what we can...
 
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Discussion Starter #17
Us "old schoolers" call it "Plug Chops". Ya toss a plug wrench in your back pocket, and (on a warmed engine) rip it down the road wide open throttle. Just as you are releasing the throttle, pull in the clutch and kill the engine. Pull off to the side, and pull your plugs, and read them. Take it back to the garage, and adjust your main jet accordingly. Do the same for 1/2, and 1/4 throttle positions, for your needle height, and pilot circuit.

I suppose, you could do the same thing with software to tune the ECU using the same process. I would think it would at least get you pretty close. Still, the best way to tune any of them (especially injected engines) is on a Dyno. We all don't have that luxury, and do what we can...
Agreed, a dyno (with a good operator) is always best but I find the WRT to be the best runner up I've found so far. It will let you tailor/target AFR's down to specific RPM's and throttle positions, such as raising or lowering the amount of fuel delivered at 7200 rpm without impacting 7000 or 7400 rpm AFR's. It also does other things like reflash the ECU at will to apply or remove restrictions, change fan on temp, filter out AFR readings from unwanted cold engine temps or low RPM's, etc. Many dyno's can also connect to the 8-pin connector on the WRT hardware and not have to install their O2 sensor saving time & work on the dyno.
 
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