Plug Fouling too quickly. So I did a test. Help, -Pics-

[Black]

My bike has been sitting, waiting for a wheel for about three weeks. I start it up once or twice a week to keep it in shape, let it idle on choke for awhile and then at idle for a while (til it dies ).

I checked the plugs this morning because that is what made it die on my last time it went. They were pretty bad. I'm not sure if they are "fouled" but I assume they are getting really close. These are about a month and a half old.

Pics:


1, 2, 3, 4.

com/albums/b107/Pretech/P1.jpg[/IMG]

1, 2
4, 3


#1 and 2 were bad. #2 had some oil and gunk on it. #3 and 4 were not as bad.

Now I put some new plugs in. It started right up. I'm used to playing with the choke for a minute. So I let it idle with the choke on at 3k for about 2mins, then lowered it to idle w/o choke. Once it was pretty warm, I rev'd it up a few times. Gradually to about 8k, then blipped the throttle from about 2k to 8k a few times.

Here are the pics after maybe 4 minutes run time:

#1 and #2 amazed me. #3 looked perfect, and #4 was a tiny bit darker.





Questions:
1) What is making my plugs do this? Do I need to adjust the carbs to less rich on #1 and #2? I don't like to do carb work, just don't feel comfortable. If it's easy I'll give it a try. I've taken them apart and cleaned them but thats all.

Thanks,

Sam

[md86]

Well , letting it run at idle for too long , ESPECIALLY with the choke on , is NOT good . But actually , the insulator's on most of them look pretty good (bottom pics where they're almost white/kinda tan). I call THAT pretty good , anyway . When mine's running right , that's what they look like . But that ONE black one :-k ..... THAT'S not great ...

[katana bob]

not to hijack your thread, but did you get the package I sent you?

[Black]

pmd.

and md86, the tan is normal after such a short time period? I've seen it in normal looking plugs that have been used for awhile but I've never done a test this short to see what they look like. And yes #1 and #2 worry me the most.

I have been letting it idle for awhile to get the gas out of the bowls so I don't have the carb clogging problem I had when I first got the bike. Since I can't ride it I just start it up and rev around for a little while. This is bad?



Thanks,

Sam

[md86]

Yeah , the "honey" color is actually what people used to look for back in the day , and you'd get it in just ONE good pull on brand new plugs . But nowadays , what I seem to hear is that "good" plugs are nearly white . But "not black" is good enough for me ! Idling for a while does tend to crap plugs up a bit , too .

[The CyberPoet]

I'll cover this again real fast:

(A) Whenever you run the bike on choke, you're loading up the plugs with carbon fouling because the mixture has excess fuel in it. Suzuki's word on this is choke only as much as required to get the engine to 2k and shut off the choke within 30 seconds (use the throttle if you need longer to get it to idle stably on it's own).

(B) Plugs are self-cleaning once they reach their operating temp range (somewhere between 500 and 850 degrees C for standard NGK's); in this range they burn off the fouling. Thus, it makes sense to let the bike warm up enough to burn off all the fouling before shutting it down again, or you're just building up crud every time you run it.

(C) The second plug indicates that this particular cylinder isn't reaching full temp at the same time as the others. Whether that's due to an overly rich fuel-air mixture rate, a bad carb sync, loose or damaged valves, poor compression I can't determine just by these pictures. Suggest you use a thermal probe on the exhaust headers to see if they are coming up to the same temps at the same rates (#2 probably isn't)...

Good Luck!
=-= The CyberPoet

[md86]

Thermal temp ? Just reach out and grab the thing . Seriously , I spit on my finger and TAP the headers . If the spit evaporates IMMEDIATLEY , it's getting hot enough . If not ......well , then there's a problem !
And like I said , even with my bike LEAKING oil (which it ALWAYS seems to from SOMEWHERE) , I STILL don't use anywhere near an extra quart every oil change .

[The CyberPoet]

Thermal temp ? Just reach out and grab the thing . Seriously , I spit on my finger and TAP the headers . If the spit evaporates IMMEDIATLEY , it's getting hot enough . If not ......well , then there's a problem !
And like I said , even with my bike LEAKING oil (which it ALWAYS seems to from SOMEWHERE) , I STILL don't use anywhere near an extra quart every oil change .

I suggest you not follow MD's lead on this (too easy to leave skin behind), and instead use a spray bottle of water or a kitchen temp probe if you don't have a laser thermal probe handy.

Cheers,
=-= The CyberPoet

[katgozoom]

It's true. Running too long on choke will foul your plugs - but it would foul all of them. You can check temp and all that jazz if you want, but the bottom line is you've got differing mixtures across cylinders, with Nos. 1 and 2 set richer than 3 and 4. Cylinder No. 2 is choking in fuel.

If prefer the KISS method ("keep it simple, stupid"). Put in a set of new plugs and before you run it, sync the carbs. If that still darkens/fouls one plug significantly more than others, you've got something wrong or dirty in the carb artificially richening the mixture in that cylinder.

Go to plan "B": disassemble and clean the carbs. Since it's unlikely that the mixture "wandered" that far out in cylinder No. 2, I'll predict that your No. 2 carb is sticky/dirty. Let us know what you learn.

By the way, you said you were waiting on a wheel. What happened to your old wheel?

[Black]

I think I'll take the carbs off and clean #2 out, hopefully a simple cleaning will fix/help it. What do I do to lean out the mixture in cyc. 2? (the easiest way) Turn a jet clockwise somewhere? (I 've cleaned my carbs but I let the show sync them so I havent learned how yet)


I hit some gravel and hit a curb, landing in the grass. Learned a lot that day also. Sinfulkat said he sent it last friday but I havent got it. I've missed A LOT of perfect weather.

Thanks-

Sam

[ThAzKat]

A little white is what a good running stock bike will have because they are lean from the factory. a Brown/tan color is perfect in the real world. That means all is well in the little engine. you #1 is ok, #2 is for sure not good, #3 is great and so is #4.
I guess without being there to diagnose your bike personally I would have many questions to ask you.
#1 what have you done performance wise to the carbs?
reason for this question is because when most do their jetting kit they use the same size jet accross the board.
#2 how long has it been since you cleaned the carbs?
#3 have you synchronized the carbs lately?
#4 have you adjusted the air/fuel mixture?

[Black]

Answers:
1. All stock. I'm keeping this bike as stock as I can for now.
2. I cleaned the carbs in about June. I have Techron in it right now, I had some left over so I figured I'd try it out.
3. The carbs were synch'd by the shop about a month ago. I figure maybe they got #2 carb way off and the others good... and
4. I am assuming they adjusted the a/f at that time as well. I haven't touched it.

What do you think?

Thanks,

Sam

[ThAzKat]

adjust air/fuel mixture

do a idle drop, you can find that info of the process in your manual or on here.