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Black spark plug

Joined Mar 2005
3K Posts | 3+
Mesa, AZ
What would be the reasons for my spark plugs getting so dark after each ride, basically?

I attached the photo of the plug. I had one ride and then several start attempts yesterday, tinkering with the idle. Basically the bike would start and die after a couple seconds, except once when I pulled the throttle.

This morning I tried again, but decided to inspect the plug and when I saw that it looked like that, I changed it and put a new plug. Then the bike started...

If I need to buy a new plug per ride, that's a bit expensive but that's more fun than a movie ticket.

Actually I'd to find out what's going on here and fix it.

Thanks for your input!
 

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there's nothing wrong with that plug. i can see some deposits on the edge of the photo but it should start.

get ken to check the ignition timing. if it helps: undo the peep hole and if the line in the stator isn't only 1/3 of the way from the left-move it! if it is a third of the way away from the right then MOVE it!

do the kickstart plate mod that i showed you. clean all the connections and then dip in silicon.

get a new plug cap. the factory recommend a new one every two years AND THERE MUST TO BE A REASON.

you had a keihin FCR once and you then sold it. was it worth it?

no.

i start mine first or second kick and it has been tuned!

another thing you should do is tell me how long the bike likes choke for in the morning. it's an old subject of mine and i even offered it up as a seperate thread just for you nick. so tell me about the starting set up reference needing choke and for how long.

regards

Taffy
 
Bike starts with new plug, not with dark plug.

I don't remember a skid start plate mod, sorry.

The ignition timing we checked it a few times already. Nothing wrong there.

That FCR would not fit, it would not work, this is why I sold it. One minute you tell me the carb is fine, the next you tell me to replace it.

Now, if the plug is dark, could it mean too rich a mix?
 
Bike starts with new plug, not with dark plug.
I KNEW THAT AND STAND BY WHAT I SAID. THERE IS NOTHING WRONG WITH IT.

I don't remember a skid start plate mod, sorry.
I HAVEN'T MENTIONED A SKID START PLATE?

The ignition timing we checked it a few times already. Nothing wrong there. I DON'T GIVE A FIG! GO CHECK THAT LINE AND IF IT AIN'T TO THE LEFT OF THE MIDDLE OF THE HOLE: MOVE IT!!!!

That FCR would not fit, it would not work, this is why I sold it. One minute you tell me the carb is fine, the next you tell me to replace it. THAT'S BECAUSE NOBODY WITH AN FCR HAS ANY TROUBLE AND THAT'S WHAT LIFE IS ABOUT. NOT HAVING TROUBLE-WELL ISN'T IT? AND I THOUGHT YOU DID HAVE A PROPER FCR?

Now, if the plug is dark, could it mean too rich a mix?
NOTHING WITH THE BLOODY PLUG. NOW TELL ME ABOUT THE STARTING PLEASE!

regards

Taffy
 
I am not buying an FCR for $700. Rather sell this one and buy a newer bike, like an 03.

I will keep a Dellorto on this bike and tune it.

This is the reason of my question. Finding out why the plug is dark with sooty deposit on it (I wiped some off that you can't see on the photo) will help me.

Now, please, for the last time: stop telling me to put an FCR, ok? I got the message already.

The ignition timing is fine.
 
$700 aha!

only trying to help so that we can get onto another subject...

so what's it like on choke then!

PM me your email address and i'll send you the three photos direct. unfortunately i can't upload photos to the site for some reasonat present because it thinks i'm not a member when i do.

oh and nick, i love it when you're angry!

:D :D :D

Taffy
 
I am not angry, my boys are currently trouncing the Afrikaans and it's almost as enjoyable as winning at Twickenham.

Also, the FCR I had was a 39. I'd rather get a 41. I wonder what would be necessary to install the FCR, besides new rubber air boots... I wonder if the throttle assembly from a KTM 525 would work? (For next time someone parts one out).
 
Frog,
That plug looks better than the one in either of my two bergs and they start every time within two revs on the button.. Cold... check your timing again. Oh, and they both have Dellorto carbs.
Dez
 
first of all my photos have just arrived and so go see them in my gallery over here

secondly, so you DID have an FCR! my bike is in a high state of tune and i could only tell i had a 41mm carb on in 6th when i couldn't even see the road!

thirdly, you don't need a new boot with the FCR. you just modify the inlet stub.

how the hell did you boys ever win two world wars anyway?

fourthly, choke again? 8O 8O

regards

Taffy
 
Choke one 3 first kicks, then no choke, usually two more kicks.

If no start, open throttle, decomp, 5 or 6 fast kicks, then usually up to 3 kicks.

If after 30 to 50 kicks the bike has not started then I roll it into the garage and vent my frustration over here.

I see a FCR 41 on eBay, $150, 2 days to go, but I bet you it will end up at over $400 pretty quickly.

$700 is for a new FCR 41, $300 to $500 on eBay, but I am sure the Dellorto will be fine. I guess I can give another look to the ignition time, but the stator may also need to be replaced, if it does not give a good spark at low rpm, and I mean 3000 rpm, that may be the cause.

New plug cap? That still can be added into the mix.
 
A plug will look like that if you run the choke to long. I have seen them darker than that and still work with no problems. Check the vent hoses to make sure they are open. Another thing check the coil wire from plug cap to the coil, they will work loose and the plug cap for tightness. That will give you some ideas. Hope this helps.
 
try moving it 3mm as the eye views it to the left as you view it.

are you trying to start the bike with the red lever pointing at 'high'?

nothing wrong with the plug.

did you ever move the kickstart around one spline so that to get it to sit in nicely against the case: you have to pull it back to tuck it in?

regards

Taffy
 
That spark plug isn't black.?I Good photo, though. It looks like it is a little blistered from heat. If the ceramic is dark, then certainly the rest of the shell and base electrode should really be black. Rich carbon deposits are fluffy or flakey, not glazed looking. Plug should have some color if it's been ran for any length of time. I'd richen it up and then run it hard, cut the ignition at WOT and pull the plug and look at it. If that is glazing I'm seeing, it is conductive and will foul the spark. Concerning the two world wars, we couldn't have done it withhout the English!
 
What is WOT?

doctorcorey said:
Concerning the two world wars, we couldn't have done it withhout the English!

And the Russian. And the Resistance from all the occupied countries. I think it was great team work overall. Good job, everybody.
 
Don't forget the fine Canadians. :)

WOT = wide open throttle.

You can sometimes see WFO which is basically the same thing. 8)
 
Taffy said:
try moving it 3mm as the eye views it to the left as you view it.

are you trying to start the bike with the red lever pointing at 'high'?

nothing wrong with the plug.

did you ever move the kickstart around one spline so that to get it to sit in nicely against the case: you have to pull it back to tuck it in?

regards

Taffy

What red lever are you talking about, Taffy?
 
Ok, I removed the cover, set to TDC and discovered that there are two marks... Is this normal? (I think that someone added the mark on the left to "advance" the ignition)
 

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I tried to adjust the stator by turning it but it appears to be glued... Impossible to move, even after untightening the #4 allen bolts.
 

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When I put the cover back and the piston is at TDC, the "glued" stator is right in front of the left mark.

My guess is that it was set this way and glued to avoid losing the setting.

If I were to remove the stator to change it ... I'd have to wrestle a bit, I guess.
 

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