Spark plug Check

[dubepj]

I've heard that to check spark plugs correctly for lean/rich conditions it should be done just after a ride so they are hot. 
Why it that??  i would prefer check checking when cold to avoid burns.

[Burnout]

Reading spark plugs is not a difinative thing, there is not a whole lot of info there that does not show up in other areas.

Today's pump gas does not color the plug as leaded gas did.

When looking at plugs, you are looking for signs of badness more than anything else.

[Hossamania]

The best way to check plugs is while running with an afr meter.

[Deye76]

If your going to pull plugs on a hot motor, make sure they have some copper anti-seize on the threads before doing so.

[david lee]

dont you check plugs hot when determaning what main jet size to use

[Hossamania]

dont you check plugs hot when determaning what main jet size to use

Reading spark plugs is not a difinative thing, there is not a whole lot of info there that does not show up in other areas.

Today's pump gas does not color the plug as leaded gas did.

When looking at plugs, you are looking for signs of badness more than anything else.

In the good old days of lead gas, it was possible to read plugs to determine jet size, somewhat. Not an exact science, and took some experience. With today's unleaded fuel, it's pretty tough to do.
Get an afr meter.

[Hossamania]

Yes. I don't know a specific model, and that one may work, but that is the concept.

[Burnout]

http://www.daytona-sensors.com/wego--systems.html

I have a dual unit that includes logging.

You have to be fairly committed as you will need to weld bungs into the exhaust for the sensors. I recommend using long bungs, many supply only short ones.

[Deye76]

A good dyno tuner can assist with jetting.

[turboprop]

I've heard that to check spark plugs correctly for lean/rich conditions it should be done just after a ride so they are hot. 
Why it that??  i would prefer check checking when cold to avoid burns.

Lots of noise here. This evo of yours most likely has a recipe that's been done thousands of times and has known jetting and timing requirements. if it has a carb, it is not that complex. The arm chair crowd will chime in with noise about various things, but in the end they really mean nothing for a typical street evo build.

Try this, list as many details about your engine and the chassis (lightweight dyna or heavy barge bagger), and ask for known jetting combinations. Pay attention to the guys that have been tuning bikes for a while and be forewarned that many that respond will be either shooting from the hip or regurgitating something they read online.

[kd]

Good advice there.

[xlfan]

http://www.daytona-sensors.com/wego--systems.html

I have a dual unit that includes logging.

You have to be fairly committed as you will need to weld bungs into the exhaust for the sensors. I recommend using long bungs, many supply only short ones.

Is the long bungs for less zirconium exposure, or less flow resistance?

[JW113]

Spark plugs can be used for a general diagnostic measure for certain problems. If they're dry and jet black, obviously too rich. If they're caked with gooey sludge, you have an oil problem. Et certera, et cetera. As already mentioned, reading plugs for A/F ratio has gotten a lot harder. I think you can still use the plugs, along other visual/behavioral indicators, to get a carb jetted to run "good enough", but as I've found out, without a AFR meter, pretty hard to dial it in dead nuts on. And yes, love the Daytona Sensors WEGO unit.

-JW

[david lee]

Spark plugs can be used for a general diagnostic measure for certain problems. If they're dry and jet black, obviously too rich. If they're caked with gooey sludge, you have an oil problem. Et certera, et cetera. As already mentioned, reading plugs for A/F ratio has gotten a lot harder. I think you can still use the plugs, along other visual/behavioral indicators, to get a carb jetted to run "good enough", but as I've found out, without a AFR meter, pretty hard to dial it in dead nuts on. And yes, love the Daytona Sensors WEGO unit.

-JW

have you used gordons color tune

[SP33DY]

have you used gordons color tune

It's Gunson Colortune

[Wookie3011]

I found thin video very informative. GMR, Baxter, Tatro and George Bryce all are great to watch!! Any others I'm missing? I know there has to be a few more. Anywho, its something.

[turboprop]

Spark plugs can be used for a general diagnostic measure for certain problems. If they're dry and jet black, obviously too rich. If they're caked with gooey sludge, you have an oil problem. Et certera, et cetera. As already mentioned, reading plugs for A/F ratio has gotten a lot harder. I think you can still use the plugs, along other visual/behavioral indicators, to get a carb jetted to run "good enough", but as I've found out, without a AFR meter, pretty hard to dial it in dead nuts on. And yes, love the Daytona Sensors WEGO unit.

-JW

I remember telling you to try this and you getting pissed at me. Very happy to see you are a believer. Not sure how I ever tuned a carb without one. Seriously.

To add to the fun, I have, like everyone else, a bunch of friends that have been tuning carbs by ear and seat of their pants since gasoline was invented. They know everything. Don't need no stinking gauge, etc. I had a $100 challenge going for a while. Bring a bike to my garage, adjust the idle AFR to be optimal and then let me put my sniffer up the pipe. Have never seen a bike adjusted by an expert that was anywhere close to 12.5-14:1 AFR. Most were typically around 10:1 some where dangerously lean. Most were amazed at the precision of the AFR gauge and how such a small rotation could have such a drastic affect on the AFR. Most were reluctant to admit that learning occurred. Fun times.

[Breeze]

" Have never seen a bike adjusted by an expert that was anywhere close to 12.5-14:1 AFR. Most were typically around 10:1 some where dangerously lean."

? 10:1 dangerously LEAN???

[Hossamania]

" Have never seen a bike adjusted by an expert that was anywhere close to 12.5-14:1 AFR. Most were typically around 10:1 some where dangerously lean."

? 10:1 dangerously LEAN???

Two different statements being made. Most were rich at 10:1, some were dangerously lean.

[Breeze]

^^^^^^^^^^ Rereading it this morning I see my error.  I read it several times yesterday but my mind kept seeing it wrong. Damn oldtimers. Thanks

[turboprop]

" Have never seen a bike adjusted by an expert that was anywhere close to 12.5-14:1 AFR. Most were typically around 10:1 some where dangerously lean."

? 10:1 dangerously LEAN???

Yes, Most were around 10:1, while others were dangerously lean. By that I mean 15:1 or higher.

[mkd]

i got all about the powercommander that was on my bike yrs ago and decided to do a few spark plug checks. did never find out too much but i did manage to bugger the threads up pulling plugs on my 2005 eglide efi. back plug was stiff all the way out and all the way in for ever after. I learned a hard lesson pulling plugs with a hot engine.

[Burnout]

A touch of never-seize goes a long way.

[Ironheadmike]

Spark plugs can tell you a lot . Fuel mixture,the correct timing, also if you have bad rings or valves . If you use never seize you will muck up some of the readings . Also NEVER take a plug out of a hot motor . You will risk of pulling to threads out . Remember aluminum is soft when it is hot .

[Hossamania]

Spark plugs can tell you a lot . Fuel mixture,the correct timing, also if you have bad rings or valves . If you use never seize you will muck up some of the readings . Also NEVER take a plug out of a hot motor . You will risk of pulling to threads out . Remember aluminum is soft when it is hot .

How does never seize muck up the readings?