Input on plug chop photo

[zuzu]

This is my first attempt at a plug Chop. I drove the bike about 3 miles to warm it up. I then ran at around 3500 RPM for 3/4 of a mile to get my Pilot circuit readings. When I neared the driveway to my house I pulled in the clutch and killed the engine, then proceeded to coast into the garage. I pulled the plugs and this is what I found. The tips are fairly shinny.

The bike was jetted with a DJ jet kit back in the mid 80's. Stock Mikuni adjustable needles set at 3 down. Pilots are 45.0. I just installed new 135 Mikuni mains jets because the DJ main jets were corroded from sitting for 18 years.

The Bike runs real strong, but I believe the pilot circuit to on the lean side. I do have a 47.5 pilot jets ordered. Mixture screws 4 turns out.

Your opinions?

 

[Redman]

Sounds like you have the procedure correct. ANd keeping the plugs in order and lableing them is a good idea also. And asking for opinions here on GSR is a good idea too. But what folks really need to see is the ceramic part of the spark plug, so pictures from an angle would see the cermaic part better, need to see the end around the elctrode and up the side and up into the plug some. And could get closer up view of the plugs if they were arranged right next to each other. Does your camera have 'fill flash'? Does your camera have 'macro' for closer up focus?

Maybe some folks here can give some opinion based on the photos, but closer up photos would be better.

 

[zuzu]

I took the bike for a longer ride. The outside temp here is in the 30's with spots of rain, not a fun day to do plug chops. Here is a new set of photos plugs with more of the ceramic showing. There is a Very ligh to light brown ring at the tip of each plug. All are close in appearance.

Thanks for any input.

 

[walt]

to me they all look correct. next would be check them again next summer in hot weather for the same light brown you have now. you do want the motor to spend a minute or so warming up from a cold start so that cams get a good oil flow before you ride away. having the pilot screws set at 4 turns out is a sign the pilots may need a step up.

 

[zuzu]

to me they all look correct. next would be check them again next summer in hot weather for the same light brown you have now. you do want the motor to spend a minute or so warming up from a cold start so that cams get a good oil flow before you ride away. having the pilot screws set at 4 turns out is a sign the pilots may need a step up.

Walt,

I have a set of 47.5 Pilot Jets on order.

I did the test again yesterday and #2 had a very slight grayish look at the end of the porcelain. I believe this to be lean. I am going to turn the Mixture screws out another 1/2 turn.
I started with the mixture screws 3 turns out. Since setting them 4 turns out, the throttle response has improved in the low to mid end range.

Thanks Again.

 

[Steve]

With the mixture screws 4 turns out, it's time to get the next larger size pilot jet. The 47.5s you have on order should do the trick. When you get them in, start with them two turns out. Sounds like you know how to procede from there. \\/


.

 

[tone]

Any stutter or holding back on the changover from primary to main jets this should show up anywhere around 3000 4500 rpm ????

 

[zuzu]

Any stutter or holding back on the changeover from primary to main jets this should show up anywhere around 3000 4500 rpm ????

Tone,
No problem there. In fact around 4500 is where the bike really starts to pull. The acceleration is nice and smooth starting out, till top end.

I did get a ride in today with the mixture screws 4 1/2 turns out. It seems that was to much. The plugs where sooty and the performance suffered. Also it would idle down and die once in a while.
I turned the Mixture screws back in to 4 out and she is running strong again.

Do these bike have more performance in warmer weather? It was about 40 degrees out today with lots of humidity.

Thanks

 

[Ironriot]

Cold dense air is always better for any engine so I'd venture to say that cold weather helps your engine really breath. Although it could be because your bike would be a little on the lean side

 

[Guest]

What mods are on the bike besides the DJ kit?

 

[tone]

Tone,
No problem there. In fact around 4500 is where the bike really starts to pull.

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

one little known fact is that the latest unleaded fuels do tend to leave a little soot deposit even when running lean which makes things that little bit more awkward when looking at plug colour

hope it helps tone

 

[zuzu]

What mods are on the bike besides the DJ kit?

Chef

1982 GS1100E

1168 Wesco Bore Kit, Flow cut heads, K&N individual Filters, Super-trapp 4-1, Dyno Coils and wires, Kerker Jet Kit.

BTW, I have 12 Diffuser Disc's in the Super Trapp header.

-----------------------------------------------------------------------

Tone,

I will try and get a full throttle plug chop this week. Problem is were are expecting lots of rain all week, so it might have to wait a few weeks.

 

[Guest]

Are you running the stock cams?
We have similar setups. I run a 47.5 pilot and the idle adjustment screws out 2 turns and they could stand to go out another quarter turn in the colder weather.
The DJ needle is set at two notches from the bottom and shimmed lean a half notch.
The main is the DJ 138.
The bike pulls strong through all stages but stumbles of idle a bit when it's cold outside. The oil cooler doesn't help in the winter either.
I have Webcams at 340 lift and have them degreed via their instructions. (Can't remember the numbers.)

You might find the mains to be on the rich side.

 

[tomcat24551]

Zuzu--

Just curious--did you start the first plug chop run with new or freshly cleaned plugs?

Do you clean the plugs between runs (if so, how?) or do you read the sucessive runs without cleaning the plugs?

Thanks for the info.

Tomcat

 

[zuzu]

Zuzu--

Just curious--did you start the first plug chop run with new or freshly cleaned plugs?

Do you clean the plugs between runs (if so, how?) or do you read the successive runs without cleaning the plugs?

Thanks for the info.

Tomcat

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?

 

[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.


.

 

[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

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.