Input on plug chop photo

[Steve]

Personally, I have always been leary of cleaning plugs with a wire wheel. Any time I have tried it, it left the porcelain with a metallic sheen that I felt would be electrically conductive, preventing a proper spark.

Sand (or other particle) blasting works a bit better, but I have also seen conductive particles get stuck in the deep recesses and cause problems, too.

New plugs are relatively cheap (like me ), so I will get new plugs to do plug chops. A new plug with very light deposits will not take long to get good readings. If there are heavy deposits, another set of new plugs will be purchased. When you finally have your jetting dialed in, just install your 'new' plugs with the heavy deposits. In a few miles, they will be just as clean as they should be, and you will still have another set of new plugs waiting for the next plug change interval, as plugs don't deteriorate over time, sitting in your parts box.


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[zuzu]

Over the years I have used a Sand blaster with great success. I always blow the plugs out real well. Although most of my use was in auto's.
I went to Harbor Freight yesterday and the have one for around $16.00, I have 3 sets of like new plugs. I am thinking of stopping by there today and picking one up, If I don't see anymore objections about there use this morning.

Before I started this thread I had search the archives for the information that we have covered in this thread without much success. I was able to find bits and pieces about doing a plug chop and interpreting the results.
I hope all of the great People here at GS-Resource will add more information to this thread. It could be a great asset for other people in the future.\\/

Thanks,

[tomcat24551]

Cleaning plugs

If you're on good terms with your dentist, ask him to give you a set of dental picks that he's retiring from use. (He ought to be willing to help you out--you've probably paid him a fortune!)

Plugs can be cleaned safely by sandblasting if you use a "pick" with a long, fine and sharp "business end" on it to remove the grit that gets lodged between the base of the insulator and the plug shell. You need a magnifying glass, too--and a good light.

The plug will capture some of the grit and you need to get it out of there!

Tomcat

[49er]

Tomcat,

The plugs where like new and cleaned before each test with the wire wheel on my bench Grinder, then the porcelain was cleaned with starting fluid and a q-Tip.
I probable should pick-up a new pair of plugs for my next test. I wonder how much SPARK PLUG CLEANERS are at Harbor Freight?

If the rest of your range has been checked and is running cleanly, you don't need to clean your plugs between pilot circuit tests. If the plugs are dark and sooty on the pilot circuit and you lean off the mixture screws for your next test, just take the bike for a blast before re-doing the pilot plug chop. This will burn excess carbon off ready for the pilot test.
I never clean my plugs with a sandblaster for the same reasons mentioned by Tomcat 24551. In fact, I never clean them at all, only replacing them every 20K kms. I do carry a spare on the bike in case one claps out. I haven't had to use it as yet!!

[KEITH KRAUSE]

Okay from that & the look of the plugs i'd say you are very close & doubt the primary jets need changing, around 4000 rpm would be the changover from primary to main jets so i'd leave the primary's alone do a plug chop at higher revs & see that the plugs tell us then :-D

Regarding which jetting circuit is regulating mixture, it's not about rpm's, it's about throttle position.
Any other reference just causes confusion. These bikes are not anywhere near the main when operating at 4K under normal/correct throttle use.

[trippivot]

I think you have a good start on what is going on in your carbs.

but I 'd like to offer a thing or two:

tunning at 40 deg F is a bit too cold to trust the settings you are adjusting for any other time but Winter.

next..I may be wrong but I think you might be confused about adjusting the pilot jet size and mixture screw setting for throttle response at 4500 rpm. By that time you are on the needle jet circuit- and the transition smoothness comes from the needle groove setting.

the pilot size and mixture screw setting are for idle and just above idle (0 throttle~1/4throttle opening)=950rpm~2000rpm.

after 2000 rpm you are lifting the needles and slides (1/4 throttle~1/2throttle)= 2000rpm~6000rpm adjustment is made at the grooves and shim setting inside the slide on needle jet height.

above 6000rpm is of course the mains

I like crisp throttle response and just want to help. I do the plug chop test but only once in a while not often. i shoot for chocolate brown half way up the inner electrode (pump gas) (medium gray on 110 leaded gas)

when I'm making jetting adjustments on rideability I use the choke/enrichener as a guide.... pull the enrichener at a specific rpm or throttle position and if it begins to run better it needs to be richened up if power falls off lean it out.
that is a crude test but will give you a sign post to know which way to go.

[zuzu]

KEITH KRAUSE

Regarding which jetting circuit is regulating mixture, it's not about rpm's, it's about throttle position.
Any other reference just causes confusion.

Thanks for putting this into proper prospective.

trippivot

think you have a good start on what is going on in your carbs.
but I 'd like to offer a thing or two:
tunning at 40 deg F is a bit too cold to trust the settings you are adjusting for any other time but Winter.

I agree! It is to cold out to get correct Readings. I got in a ride today and the bike is running good.
Here is a picture of one plug after wide open throtle for about 10 blocks going up hill in 3rd gear. I think it reads alittle lean. I am going to wait till the weather warms up and retake some more Chop readings.

Thanks All. I hope you all have a Mery Christmas!

[KEITH KRAUSE]

Any kind of tan color is acceptable. Factor in that you're testing in very cold air (more oxygen in the air/leaner), I'd guess that in "normal" temps, that plug will darken just a tad more and you're good.
Merry Christmas to you too!:-D

[zuzu]

Update

UPDATE


I got the 47.5 Pilots a couple weeks ago. I installed them last Thursday and set the Pilot Mixture Screws at 2 turns out. I also up the main jets to 140"s while I had them apart. After I got the carb's back on I took it for a ride, the temperature was around 38-40 degrees outside. Close to the same ambient temperature that I did the earlier Plug Chops at. Overall the bike performed about the same on the pilot Circuit, but pulled stronger at WOT. I got my popping back when decelerating and once in awhile at idle. I pulled the plugs and found dark brown soot on the tips and ceramic's. I was also getting black puffs out the exhaust when I would roll it open quickly. I am sure it was running to rich.
This morning I pulled the carb's again and put the 45.0 Pilots back in with 4 turns out on the Air Screws. I was only able to get in a very short ride about 2 miles because it started to snow. I lost the popping almost completely. It purs at 1200 Rpm's and ran smoothly at a steady speeds 35-40 MPH. I know that I need to get in a longer ride for a better evaluation.
I am just going to wait till the weather warms up, get the carb's Synchronized and repeat the plug chops. As Kieth said it will run richer in warmer weather? It is way to cold to try and tune anymore. I might be able to go up on the mains but that will half to wait till spring.
Any Input would be appreciated.

[49er]

UPDATE


I got the 47.5 Pilots a couple weeks ago. I installed them last Thursday and set the Air Screws at 2 turns out. I also up the main jets to 140"s while I had them apart. After I got the carb's back on I took it for a ride, the temperature was around 38-40 degrees outside. Close to the same ambient temperature that I did the earlier Plug Chops at. Overall the bike performed about the same on the pilot Circuit, but pulled stronger at WOT. I got my popping back when decelerating and once in awhile at idle. I pulled the plugs and found dark brown soot on the tips and ceramic's. I was also getting black puffs out the exhaust when I would roll it open quickly. I am sure it was running to rich.
This morning I pulled the carb's again and put the 45.0 Pilots back in with 4 turns out on the Air Screws. I was only able to get in a very short ride about 2 miles because it started to snow. I lost the popping almost completely. It purs at 1200 Rpm's and ran smoothly at a steady speeds 35-40 MPH. I know that I need to get in a longer ride for a better evaluation.
I am just going to wait till the weather warms up, get the carb's Synchronized and repeat the plug chops. As Kieth said it will run richer in warmer weather? It is way to cold to try and tune anymore. I might be able to go up on the mains but that will half to wait till spring.
Any Input would be appreciated.

I think you may be confusing your mixture screws with air screws. With the #45 pilot jets in, at 4 turns out on mixture screws, you will be running richer than at 2 turns out.
Re-try your 47.5 pilots at 1&1/4 to 1&1/2 turns out.
I recently dynoed my engine and found that I was running slightly lean on my pilot circuit. I richened the mixture screws by an extra 1/2 turn and improved my response significantly in the 3000-4000rpm range under moderate throttle. This is the area where the pilot circuit and needle circuits are overlapping. It is a vital point of tuning to get right for good torque.

[zuzu]

trippivot

I tried the 47.5 jets first at 2 turns out and then iurn them in to 1 1/2 turns out to lean out the Pilot circuit, it made no noticeable difference. I am referring to the Pilot Mixture screws. I have the 45.0 jets 4 turns out to richen the pilot circuit. But till the weather warms up I can't get it more accurate.

I read your post about your Dino results. Nice, I am not sure if there is a place around here that has a Dino setup. In fact its hard to find a good tech at a good shop in my area.

[KEITH KRAUSE]

Once it's warm enough, go out with the bike fully warmed up and test at full, 1/3, and minimal throttle positions and note plug color after each test.
Up 'til now you mention the plugs change but you're not giving info at what specific throttle position/jetting circuit you were at to get those plug reads. You have to test each one and get an idea of what all 3 circuits are doing. Test, chop off, get reads.
As for tuning before re-jetting/testing, the carbs must be synched before testing/plug reading. Without reasonably synched carbs, each cylinder/plug may show a different color simply because of different vacuum levels drawing up mixture from the bowls. How do you know which to choose as your base? Unsynched, or bench synched only carbs just add a poor tuning factor to the mix. The bike must be tuned correctly so you KNOW any jetting problems are truly jetting related, though some mods don't match each other well and create problems too.
You need to verify ignition timing/advance are operating right. A good blue spark is mandatory.
Valve clearances must be correct and cam timing must be verified to be acceptable or right where you want it if you have adjustable sprockets.
I assume any decel' popping is truly jetting related and there's no chance of a header leak?
Some mods contradict each other and are a poor match. Hopefully, your porting for one, doesn't cause tuning problems that are impossible to eliminate.
If a read it right, you said it has a stage 3 DK kit but the jet needles are stock with the e-clip in position 3?? Need to know what you have for sure. Typically, when running the DJ kit, if the clip is in position 3 from the top, that's generally on the lean side. Solid 1/3 to 1/2 throttle tests will tell.

[zuzu]

Kieth,

Most all references to plug color and jetting at this time was done at minimal to 1/3 throttle. I was trying to get my pilot system jetted correctly. Then with the coming of warmer weather I will check the mains.
The Carb's were synched when cleaned, just prior to my jetting session. The only other change to the carb's, other then changing the jets was that the the needle jets were raised from the number 2 down position to the number 3 down position.
I have read many of your post and did a complete tune. Adjusted the Valves. Set the timing and checked for correct advance. Cleaned and oiled the K&N filters. Checked the spark. Compression also check and good.
The engine ran perfect before its 18 year sit in the garage. I pulled the headers off inspected them and installed new exhaust gaskets. The Popping must be from the jetting. I was able to get in a 20 mile ride yesterday and it ran great in the 40 degree weather. popping was almost non existent since going back to the 45.0 size pilot jets.
The jet kit that was installed when all the mod's were done back in the mid 80's and was called a kerker jet kit. It appears to have the original needles but they are adjustable (maybe Canadian).
I want to thank you and everyone else for there continued input. I have learned much about my bike and will continue to my growth in knowledge on how to keep it operating perfectly.