Author Topic: Spark plug color? (Read 9790 times)

theslayedsaint · « **on:** March 23, 2015, 01:58:19 PM »

I'm still really bad at telling what color my spark plug should look like, any thoughts on if this is a good color or if it's to dark?

flybox1 · « **Reply #1 on:** March 23, 2015, 02:07:40 PM »

tell us the conditions of the test.
idle? how long? ride aroung the block? what rpm? etc....
those look a little dark (rich), but getting closer

is that oil, or gas (wet) on the lip of the plug?

best to show more of a closeup of the end, looking into the plug around the insulator next time.
similar to the pictures below.

flybox1 · « **Reply #2 on:** March 23, 2015, 02:10:12 PM »

Bodi · « **Reply #3 on:** March 23, 2015, 03:32:13 PM »

Looks pretty normal for if you rode home stop-and-go before pulling them. That tends to darken plugs because the carbs run rich at idle and low throttle to help eliminate stumble. You need to ride for a few minutes at the throttle setting you want to check, cut the engine, then coast to a stop to get a true plug reading.

Vinhead1957 · « **Reply #4 on:** March 23, 2015, 03:41:21 PM »

Those plugs are too wet. Check your spark with one out against the head. Yellow is mellow. blue purplish is what you want. If spark is good, then look elsewhere. Too rich

grcamna2 · « **Reply #5 on:** March 23, 2015, 03:57:31 PM »

How many miles on your fresh top end rebuild theslayedsaint ? I hope you ran the engine hard enough to 'seat'/break-in the fresh rings;those plugs look to me like they're oil-fouled and you may be getting oil past your rings...

theslayedsaint · « **Reply #6 on:** March 23, 2015, 09:54:05 PM »

Ok... That was a lot of different answers! $:-\$
I did ride around the block no more then 15min. I pushed the bike pretty hard when I first got it running, wish I did things a little different at first start of the bike.. But hey nothibg I can do now. How do I test to see if oil could be passing the rings? Also the plug color can change that much from highway vs slow ridding or idle? Do you have to replace plugs to check? Or will it change? Man I've got so much to learn!! Thanks everyone for teaching it's been amazing to learn so much in only 2 years of ridding!!!

theslayedsaint · « **Reply #7 on:** March 23, 2015, 09:56:46 PM »

Also only have put like 5-10 miles on it

flybox1 · « **Reply #8 on:** March 23, 2015, 10:20:41 PM »

In your short ride, how many different throttle positions did you go through?
Lots, right?
With every different throttle change, your are activating different parts of the carb.....mixture screw, pilot jet, needle height, main jet and all the combinations in between, so yeah, if you are 'riding around town' and look at your plugs, they won't tell you anything. You get the mixture of plug deposits from all positions.
You test one throttle position, and look at your plugs.

ekpent · « **Reply #9 on:** March 24, 2015, 04:35:42 AM »

If it is running acceptable I would put more miles on it to get a proper break in on the rings etc. before getting too worried on the plug color. Are you getting any smoke out the exhaust ?

PeWe · « **Reply #10 on:** March 24, 2015, 05:05:25 AM »

The plugs only will not tell the entire story
I had pitch black plugs AND really hot running engine. I saw the high oil temp on the CB750 oil dipstick with temp gauge I had purchased from Yamiya750 as a fun gadget.
Flooding floats, too rich on low but way to lean between 3500-5000rpm. Important that it smells correct when idling the bike and sounds well too.

Not a D-D-D-D sound with really rich smelling smoke that will infest the clothes.
Different when not too rich on idle when the engine sounds RRRRRRRRRRR and no fat rich smell that will follow you back indoors.
When this is OK check plugs. Temp gauge is really useful.

Gooseman · « **Reply #11 on:** March 24, 2015, 05:42:51 AM »

The color of the plugs definitely will change that quickly. Pulling in the clutch simultaneously while killing the engine at a held throttle position is important to getting a good reading. If you tune/check for 1/4, 1/2, 3/4, wot, and plugs look good, how they look when idling doesn't matter much.

Personally i'd agree with saying the plug you posted looks wet, hard to tell if it's oil or gas though from pics. Do they smell like gas or no?
With so few miles on the rings though, maybe they aren't fully seated yet? Not much experience with ring seating, yet.

theslayedsaint · « **Reply #12 on:** March 28, 2015, 03:42:05 PM »

ok after a week of on and off "store" trips still not 100% confident on this thing. i've been able to get it running some what steady but also having to still use the choke all the way open, even after it warms up i still have to have it open most the way attest %60 or more. thinking i may need to go back to the bigger slow jets. one other weird thing it likes to do, is if i full throttle take off then release the throttle my engine cuts off! not aways but enough that i noticed it happening.

The pictures are after a 10min ride took off from a light pulled clutch shut off bike at about 20-30 mph 5,000/6,000 rpms hard to say for sure my rpm gauge seems to be way off.

grcamna2 · « **Reply #13 on:** March 28, 2015, 04:30:36 PM »

the plugs look a little lean to me.

eigenvector · « **Reply #14 on:** March 28, 2015, 05:29:45 PM »

I agree, they look a bit too lean.

Stev-o · « **Reply #15 on:** March 28, 2015, 06:12:33 PM »

Very lean. And if you are running with the choke on, something is wrong.
If you have stock K4 carbs, choke ever should be all the way down after 3-4 min of warm up.

theslayedsaint · « **Reply #16 on:** March 28, 2015, 11:57:05 PM »

Ohh down is off? If that's the case I have the choke off.
If there to lean should I be looking for bigger jets?

DaveBarbier · « **Reply #17 on:** March 29, 2015, 06:53:54 AM »

Quote from: theslayedsaint on March 28, 2015, 03:42:05 PM

...still use the choke all the way open, even after it warms up i still have to have it open most the way attest %60 or more.

Just saying, all the way open would mean no choke at all. I think you mean to say that you're riding with the choke still closed. Meaning you're riding with using the choke.

---
1978 Honda CB550K

eigenvector · « **Reply #18 on:** March 29, 2015, 06:59:36 AM »

I didn't notice it in this thread, but you might just go with a colder plug before rejetting or doing anything arcane with the carburators.

flybox1 · « **Reply #19 on:** March 29, 2015, 08:27:36 AM »

Quote from: eigenvector on March 29, 2015, 06:59:36 AM

I didn't notice it in this thread, but you might just go with a colder plug before rejetting or doing anything arcane with the carburators.

No.
This does not fix a mixture issue.
If you're running with the choke lever ON, you're decreasing the air supplied, creating a richer condition. Choke ON for starts, OFF after warm-up. of you don't know which way is ON, look at the butterfly valves. They will close the carb throat shut in the ON position.
I don't know whether you've run accurate plug chops or not. Your choke operation and plug chop methods are questionable...

grcamna2 · « **Reply #20 on:** March 29, 2015, 08:53:20 AM »

Quote from: flybox1 on March 23, 2015, 02:10:12 PM

What an Excellent chart

eigenvector · « **Reply #21 on:** March 29, 2015, 02:24:17 PM »

Quote from: flybox1 on March 29, 2015, 08:27:36 AM

Quote from: eigenvector on March 29, 2015, 06:59:36 AM
I didn't notice it in this thread, but you might just go with a colder plug before rejetting or doing anything arcane with the carburators.
No.
This does not fix a mixture issue.
If you're running with the choke lever ON, you're decreasing the air supplied, creating a richer condition. Choke ON for starts, OFF after warm-up. of you don't know which way is ON, look at the butterfly valves. They will close the carb throat shut in the ON position.
I don't know whether you've run accurate plug chops or not. Your choke operation and plug chop methods are questionable...

My comment was directed more toward this comment "If there to lean should I be looking for bigger jets? "
Obviously getting things to work properly is first priority. I suspect there are a few comments talking past each other here, as I see multiple conflicting replies.

The idea of rejetting to cure what at first glance appears to be a mildly lean condition seems like overkill to me. If he's running with choke on or partially on and still getting lean condition then that points toward a serious air leak, not a carburetor problem in my mind.

PeWe · « **Reply #22 on:** March 29, 2015, 02:59:15 PM »

This site has interesting plug info too. How to read all small details to verify jetting and ignition
http://honda-tech.com/forced-induction-16/***-basics-reading-spark-plug***-3063102/

Airborne 82nd · « **Reply #23 on:** March 29, 2015, 03:03:23 PM »

Quote from: theslayedsaint on March 28, 2015, 11:57:05 PM

Ohh down is off? If that's the case I have the choke off.
If there to lean should I be looking for bigger jets?

I think this is the big issue. Before anyone can give the correct advice to fix this the op needs to know how to set thing up.

theslayedsaint · « **Reply #24 on:** March 29, 2015, 03:08:39 PM »

Thanks guys I'll do some more reading up on this! So to "use" the choke I would be closing the air amount to allow for more gas? If that's the case, I'm not using the choke. When i take off the air filter I should be wanting to see it close for the "on"? So starng! Is this just me being stupid or has anyone else been confused here?

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Author Topic: Spark plug color? (Read 9790 times)