Topic: Plug Chop

[wpadgett2]

    My bike is a 1972 cb500 that I just recently got running. I did a plug chop today and I wasn't sure what to think. It looks a little lean to me but I'd like some more experienced opinions. All 4 plugs gave the same reading.

[Powderman]

What RPM were you at when you chopped it? Can't really tell much from the pic, too much shadow.

[flybox1]

throttle(slide) position during the chop is needed so we can tell you what part of your carbs needs tuning(mixture screw, pilot jet, needle clip position, main jet)....also doesnt look like you rode long enough for ample deposits to form @ that throttle position. 

see this.
http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html

[2wheels]

Did you start with new plugs?
That plug looks way to rich to me.

[iron_worker]

Agreed with the above. The area you want to look at is the base of the ceramic. You basically only need a light ring of color where the ceramic meets the steel. It doesn't much matter what the tip of the ceramic looks like.

IW

[wpadgett2]

Sorry it's taken so long to reply! The chop was done in 4th gear at 7000 rpm. I was under the impression that I wanted a lite brown fuz at the tip of the ceramic. But you saying that what I'm looking for is a lite brown ring at the base of the ceramic where it meets the steel. But what is the rest of the plug going to look like?

[wpadgett2]

And how long of a ride should I take to form enough deposits to make a proper chop?

[Geeto67]

your bike be rich yo.

the ceramic should look like a lightly toasted marshmallow. From your pics it looks like a large sooty deposit on the ceramic. Did you wipe off the electrode prior to the pic?

the chart is a little misleading - some of those "rich" plugs look oil fowled to me.

[TwoTired]

And how long of a ride should I take to form enough deposits to make a proper chop?

Depends on which metering jet you are scrutinizing.

Most begin with the main jet as this is the maximum fuel delivery restrictor.
Full power WOT, full load runs, from start to chop on clean plugs, the longer the run the better the read.
When the plugs show proper patterns, then move to mid throttle position.  Hills add loads, which is good for plug reading. Loads need power, and power needs fuel.
The pilot circuit is adjusted next for no stumble when the throttle is twisted (under load) up to one half of total throttle travel.

[Irukandji]

So I just have to ask for guidance.

How are people supposed to prepare for a plug chop run, other than clean plugs?
Most have to get to a place to run by low speed journey thru town, having an effect on the color of plugs.
After whichever run you make do you just stop on the side of the road and pull the plugs?
They'll be hot as h3ll and woudn't there be a chance of stripping the threads? Not to mention burning your fingers?
How much time should you stay at speeds suggested? Some of us dont have hills for load or quick access to interstate.
Also My curiosity is how does the trip to or from the run effect plug readings.?

[flybox1]

yeah, it should be completely up to op temps after your run, and the trip to the run wont matter as you take the reading after and have accumulated the plug deposits.  the longer your run, the better the test results.
you just need to find a good area to do it, with a pull-off area where you can work on it and be safe.
for me, new sets of plugs in, tools, work gloves, and 20 minutes.  I've previously taped marks on my throttle to indicate WOT, and 1/2 slide position.
 wot test first. I have a 4 mile section of highway with a 3 mile incline to a traffic light
quick shift to keep rpms up to start and be in 3rd or 4th gear(depending on traffic) with throttle at WOT mark for the duration, and i hit the kill /clutch and coast to the side and make a right turn into a commercial area/lot where i am out of the way.
tank off, and plugs out for a looksee.
I let it cool a bit before plugs go back in(gently) and head back to make main jet changes.
main jet needs to be changed before next test as there is crossover between needle clip position and main jet.
if i'm pretty sure i got it, then i head out for 1/2 throttle(needle clip position) test.

[TwoTired]

So I just have to ask for guidance.

How are people supposed to prepare for a plug chop run, other than clean plugs?
Most have to get to a place to run by low speed journey thru town, having an effect on the color of plugs.

Do this with old plugs to get the bike to operating temp.  Pull over, swap with brand new plugs, start up and blast down the "test track". 

After whichever run you make do you just stop on the side of the road and pull the plugs?

Yup

They'll be hot as h3ll and woudn't there be a chance of stripping the threads? Not to mention burning your fingers?

The stock plug socket has a grabber insert to hold on to the plug during extraction.  You could bring a rubber hose with you though, that grabs the upper plug insulator.
You should be using anti-seize on the threads.  Never oil.

How much time should you stay at speeds suggested?

30 seconds would be good, longer, better.

Some of us dont have hills for load or quick access to interstate.

Pity, that.  Dynos were made for those without a "test track".

Also My curiosity is how does the trip to or from the run effect plug readings.?

It confuses the reader, as he doesn't know what metering jet was dominant for the deposit pattern.

[Ewan 500K1]

WOT 

= Wide Open Throttle

[Irukandji]

TT..Thanks for that... and flybox1.

[TwoTired]

WOT 

= Wide Open Throttle

Yes.  Max power .

[wpadgett2]

    Well that's just about everything I needed to know!! Thank everybody

[lucky]

To start:

Just ride the bike how you would normally ride it for at least 100 miles.
Then when it is cooled down take the plugs out and show them to us.

That will tell us a lot more.

You did not tell us about the exhaust or intake at all.