how long do you guys run for plug chops

Finally got my first rides on my xj!! I didnt go off the side street really as im not insured and stuff yet.

Any way let her warm up til idles good and up the rd a block or too, then hit it hard til about 50 then killed the engine drifted to a safe stop. New plugs I had just installed b4 this still lean...did this about 3 times moving the mixture out about 1/4 turn maybe a lil less each time still no color really then put it away for the night.

So im figuring Im gonna have to go up some mains cus the colortune was good at idle, but should i have went on a real ride prior to this or is up and down a short block enough never went above 3rd but got it to about 50.

 

IF you run it for 20 seconds or so at 5000 rpm you should see color on your plugs. You can do this in your driveway - use fans to keep the bike cool! I pull my plugs every now and again after normal riding and check the color.
I use my color tune to get a nice blue then make it a degree or 2 richer. I find the color tune gets me just a bit lean. You should be adjusting in degrees not quarter turns.

 

Thanks bill, I was gonna go to degrees once i achieved some color was getting none.....open headers and pods knew it would be trial and error, but otherwise was running really well no miss or flat spots.

Good to know about doing it so quickly thats what I wasnt sure of, that will speed up the dialing in process.

 

Ummm, hold on here guys.............

The colortune is useful for adjusting the IDLE mixture circuit, which isn't going to have any real effect at 50000 rpms.

AND, the purpose of doing plug chops is to see what kind of combustion conditions exist UNDER LOAD, which is very different than what exists within an un-loaded engine.

Just want to make sure we're talking apples & apples here!

 

what is a plug chop?

 

Steve, do a search for plug chop or plug read. there are some really informative articles, best one is an attachment to a post. i printed it off, very discriptive & photos to go with it.

plug chop is where you run your bike for a period of time, at given RPM or speed, hit the kill switch & coast to a stop. pull the plugs & check the color of the insulators. you can do a preliminary chop in you driveway, after warm up hold your rpm's at 5k for 15 seconds, hit the kill switch. pull plugs & check insulator color.

the articles you will find in your search will better describe the process & some photos give a good idea of what color you are looking for to be spot on.

hope this helps & good luck
Gregg

 

I was thinking the samething.
When I'm doing plug chops to adjust the mixture screw I'm pulling up a hill at low rpm coasting to my garage.

 

I bring a set of New Plugs with me to a Regional FedEx Facility surrounded by a two-lane road and huge expanses for trucks to come and go.

I do a Lap like I'm in in second place with the race leader just off my front fender. When I get close to the end of the Lap ... O kill it and coast over to where I have set-up a little shop on a slight of stairs.

It's just shy of a half-mile and the straight-away on one side is damn near a quarter mile. That's where I lean on it and get the W-O-T to make the Chop.

 

Yup I realized later my answer was bit lazy. I stand by what I said about color tune. I think it does a great job of idle adjustment which if correct should be close to where you need to be. I should explain I use the "static chop" to get more in the ball park. Then as Rick has documented many times the best thing is a running test. I also monitor the color under normal riding conditions.

But Len I disagree about no effect under load or at higher RPMs since the idle circuit is supplemental richness that is used at all times. It's the only way we have of adjusting the over all mixture (short of new jets/needles).

 

You adjust the Pilot Mixture Screws to give you Idle +

The Idle will be strong when the Mixture is Colortuned.
But, relying on the Colortune Plug to "Dial-IN" the Mixture for OFF-Idle is tricky.

There needs to be a "Supplemental Richness" in the Idle Mixture to handle the Burst of AIR preceding Intake Air with Main Jet Enrichment.
It's brief. But, its necessary.
Not enough and there is a delay or a need to keep Blipping the Throttle.
Too much and you Bog-out and maybe even stall or foul the plugs.

 

Agree with Chacal . No reason or purpose) to do 'Plug Chops' in the traditional 2 stroke sense) onna 4 stroke. I do them on my Yama 350 2 stroke. But that's an entirely different engine design... and Actually V tricky to do AND read. Definitely not for beginners. as a wrong diagnosis (guess?) can hole pistons in minutes
Pull yer plugs after a few miles or regular Hiway running every few months or so to 'check' to see what's happening in there. But as a Tunning Tool for 'mixture' adjustments involving only twirling screws??
Waste 'o time in my view.

 

Wo, Danilo, better put your kevlar on you're going to get some flak.

 

Flak? Kevlar? Did you ever see the movie "No Country For Old Men" ?

Remember THAT gun?

That's what you're going to have to defend against..........


Although, I actually agree with Danilo in a round-about way. While the idle circuit is, actually, "active" all the time, past about 2,000 rpm's it's basically meaningless in the overall scheme of things. "Plug chops" are used to determine what the REAL combustion chamber conditions are under a chosen set of conditions (meaning the particular engine, in the particular bike, using a particular grade of fuel and jetting and spark advance, being operated under a particular set of conditions, etc.). They are most useful when you're trying to determine how much to re-jet when Dreaded Pods are being used, primarily because there no other "easy" way to do so, UNLESS you have access to (or pay for the services of) a motorcycle chassis dyno.....in that situation, you have a bike that can be put under load, and the exhaust gas analyzed for component output, which can then be used to "tune".

Running an engine at 5,000 (etc.) rpm in neutral, with no load upon it, tells you almost absolutely NOTHING about what the conditions are in the same engine at 5,000 rpms under a load......thus, you cannot use the Colortune in any useful way to do that type of "tuning" (unless, of course, you're trying to tune your engine to run at 5,000 rpm's in neutral in a "properly tuned" manner!).

 

Non-flak: IMHO, "plug chops" aren't as real-world significant as reading your plugs periodically after a hard ride. You don't ride at WOT much so WOT conditions aren't as important as real-world readings IN MY OPINION.

 

So here is a question.

You do your highway speed run and kill it and coast into a place where you can pull the plugs. You decide you need to richen the fuel/air at highway speeds.

What do you do? Increase the main jet size? Put a shim under the needle?