Sooty spark plug, am I running too rich?

[streido]

If my spark plug has black soot on it does this mean I need more air into the carb?

Mine is pretty black on top, not oil, more like black soot. Just tried drilling some holes in my stock air box to see if that helped, drilled 6x 9mm holes in it but gave it real low revs and no power, struggled to go over 25mph. Covered up the holes with tape and tried again and was ok. I took tape off 1 hole at a time till I had 3 open and its still ok. Need to check plug again tomorrow, but in general if its sooty does it mean I am too rich? Only on an 82 main jet.

[Resolve]

Normally if it is black and sooty it is carbon build up from it running rich.  So I would tend to agree with your assesment that you are running rich.  With the right mixture the plug should look light tanish. but not burnt.

[streido]

Im going to go buy a new plug tomorrow, I could do with changing it anyway. I think it is too rich tho, I see Ive been getting a slight build up of fluid from the carb into the airbox too so assume it from too being too rich and the excess fuel vapour from the carb is causing the fluid in the airbox. Strange tho since im only running an 82 jet?

Will try a few things this weekend, maybe try make some kind of intake for my stock box to try get more air in. Maybe me drilling holes actually let more air out instead of getting more in and thats why it bogged down so bad at 1st.

Think it must be too rich tho so I assume I can leave the main jet at 82 but just get the correct amount of air in so its not running rich then?

[slugrocket rob]

If you are running rich.... I don't think drilling holes in you air box will solve you problem. I would start by playing around with the air mix screw on your carb. Was your scooter running poorly? Are you running a good quality 2 cycle oil? Is your timming spot on? when was the last time you changed plugs? How many miles on the scooter... is it time to decarbon the head? These are the questions I would ask myself. No more holes in the air box (which should breath just fine assuming the air filter is sufficantly clean). I hope this is helpful!!

[sidthesloth]

Check the choke (enricher, auto by~starter) is working properly.

[streido]

@rob, scooter runs fine, perhaps a tiny bit off when wot at full speed if anything, but not really running badly at all.

Never changed the plug, owned it for 6 months now, looks ok apart from the soot build up, will change it today anyway just in case.

Dont need 2t oil cos its an Agility 50 4t, derestricted, stock airbox, stock exhaust, race variator, lighter rollers, 1000rpm torque spring.

13,500km on it, never de-carboned the head, wouldnt know how even if I wanted to. Do I just run seafoam or some other fuel additive type carb cleaner thro it?

Timing? Not sure, did valve gaps last week, was like this before that tho. Idle speed is set correct.

@sid, im pretty sure my choke is fine. I always start my scoot and let it idle 3-5 mins before I ride it. The back wheel spins for a mn or so then the revs lower down and the wheel stops, i assume thats the choke going off so it seems fine.

If I want to de-carbon how do I do it?

[slugrocket rob]

that's right... she's a 4 cylcle (whenever I hear fould plug, I think 2 cycle). in that case you should not need to de carbon the head (that's a two stroke thing). If it's running well, I'd put in a fresh plug and call it good.

[streido]

Rob, got new plug today, when I took old one out it was a lot better, no soot, pretty tan, almost perfect in fact. I had ran it with 3 of the holes I drilled in the air box open today. Put in the new plug anyway and did a 5-10 mile run WOT as much as poss then checked plug again, looked a little grey/white but no soot.

That was with all 6 holes I drilled in the airbox open, I closed up 3 and tried again, seems closer to tan now. Believe it or not I think the holes do let more air in and I think I was just running too rich. Going to keep an eye on it over the next week but think I just needed to get the right balance and 3 holes drilled in my stock box looks pretty good. So far anyway.

Thanks for the help/advice everyone, think I maybe ok now.

[slugrocket rob]

Good news! and yes, I am alway possibley wrong and up for learning new things. I'll add your extra holes in the air box trick to my mental toolbox! And Happy Independence Day weekend to all us on this side of the pond. Scoot On!

[ianmac]

Awesome... More air = more power... I love it.
Forget drilling holes,
Time to take that stock airbox off and install a free flow streido!

[Resolve]

Rob, got new plug today, when I took old one out it was a lot better, no soot, pretty tan, almost perfect in fact. I had ran it with 3 of the holes I drilled in the air box open today. Put in the new plug anyway and did a 5-10 mile run WOT as much as poss then checked plug again, looked a little grey/white but no soot.

That was with all 6 holes I drilled in the airbox open, I closed up 3 and tried again, seems closer to tan now.

Sounds good.

Yes the greyish white was running a little to lean with the 6 holes. and the Tan with three holes means it is running at pretty optimal a/f ratio.

[streido]

I will do the whole k&n thing soon, this was just a quick fix since it was running so rich. Going on holiday on Monday so will sort it out in a few weeks once im back home, if ive got any cash left 
Like the louder noise I get with the holes too.

Going to need a filter and also need to upjet to maybe an 88 from my 82. Also NEED a leo Vince  but thats going to be harder to do without telling the wife how much, maybe my stock box will get a hole in it, who knows, and I would need a new pipe. Wheres my hammer 

[ianmac]

Ive seen some cheaper mods that can be done with Briggs and Stratton Exhausts for under $50.00 that look pretty cool
Hard to put $300 into an exhaust if you ask me.

[streido]

I can get a chrome exhaust that looks similair to a leo vince for £45, about $70. Just not sure how good/bad it would be, maybe try it if I cant afford the Leo, its really just cosmetic anyway for me since I like the looks and noise, dont think either will offer any gains in speed really.

No cash right now anyway, holidays and the £135 I spent this week on new Bridgestones has wiped me out for now.

[ianmac]

I can get a chrome exhaust that looks similair to a leo vince for £45, about $70. Just not sure how good/bad it would be, maybe try it if I cant afford the Leo, its really just cosmetic anyway for me since I like the looks and noise, dont think either will offer any gains in speed really.

No cash right now anyway, holidays and the £135 I spent this week on new Bridgestones has wiped me out for now.

You have a link to that exhaust?
As you know the more air in the more fuel you can add... but you also need to get that air out, a good exhaust can make a nice performance difference... so its not purely cosmetic.