Carbonized spark plugs

[beerbaron]

Hello there, just got out my motorcycle yesterday. But I knew for sure it was ready for a tune-up since last year it was really rough and a little bit rich on gas.

So, Ive got a problem my spark plugs (all four) get carbonised afther only an hour and then, no fire (duh!).

Here is what I already did:

-Cleaned carbs, they are now clean. Everything seems fine

-Sync carbs, my idle is now better at low temps (they neede it!)

-Checked air intake of carb... I seem to have one air intake where the plastic is melted, don't know is it's leaking air tough

-Checked air filter (pretty sure it's not k&n), it's very clean but it has lots of oil on it, don't know what to do with it, clean it (with what?), change it ?

So what's your suggestion on this... I'm all yours. And it's gonna be very appreciated

BeerBaron

[BuzZz]

Just off the top of my head, lots of oil on the oil filter can choke off the air and make the motor run rich. You want the filter completely saturated so all the sufraces are coated but not sopping wet.

I would also investigate your melted(?) intake boot..... dat ain't right...

[beerbaron]

Thanks buzz, I'll clean my air filter and try to get rid of the oil with some Scott Towels or something. As for my melted air intake I'm gonna put some temp gasket glue so that no air leaks could come from it.

What do you think?

BeerBaron

[BuzZz]

Wrap the filter in an old towel or paper towel several layers thick. Gently wring the filter out with your hands until it is saturated but not soaking.

Now... .... just to further compilcate the issue.... what kind of oil is on the filter? Foam Filter Oil is preffered, it has lots of solvent so it goes on thin and waterery so it's easy to get everyplace, then drys to a very sticky consistancy to trap dirt. If you use this oil, wring the filter out well (but don't rip it) and let it sit for a day or so before reinstalling it. The solvents coming off the oil can affect your jetting if you run the bike too soon afterward.... so they say, whoever 'they' are, I never had a problem, but I never pushed my luck either....

If it is motor oil on your filter, be aware, it will migrate to the bottom of the filter and eventually drip off, leaving the filter less effective and making a bloody mess of your airbox and anything below it.


As for the intake boot..... seal that puppy up any way you can. What burned it anyway? Might wanna make sure it won't get burned again the same way.

[beerbaron]

The oil doesn't seem like motor oil. I remember my friend had putted some spray oil on it last year but didn't notice what type exactly.

As for the melted air intake, you are right that ain't right! But I have no idea how it happened since it's melted on the top ?? There is nothing there exept the gas tank. Maybee someone stupid passed some fire close to it ... don't know.

But just to make sure there is no leak I bought some Ether and I'll spray it aroud the melted intake, if it's a real leak the engine should stall since the air/gas ratio will be way to high, indicating me where exactly is the problem.

I just hope I'll find whatever problem is causing those spark plugs to carbonize.

BeerBaron

[mswarrior]

I don't lnow what kind of bike you have but did happen to look on ebay for a used air box to replace the damaged one.

[ronboskz650sr]

Carbon fouling can also be from a weak spark. Check your battery voltage while cranking the starter for at least 10 volts. Check the battery voltage while engine is running at 3000 rpm for about 14.2 volts. If that all checks out, check your plugs (after cleaning ) for a blue spark. Even bad wiring or plug wire caps can cause it, too, as can running premium gas in a bike not designed for it. Good luck

[beerbaron]

No it's not an electrical problem, still searching for the problem. Anyone has any idea, here is what I did afther my first post:

- Removed air bowl and still have a rich mixture

- My bike had the spark plugs specified for UK, bought the ones specified to US

Still runs rich !!! dammit I'm out of idean now. I'll check the floats level and see if they are ok. Can't seem to find any screw to adjust the gas mixture and my service manual says to adjust the floats .... I'm really asking myself what do the floats have to do with air/gas mixture ?

Anyway guys I'll wait for your inputs.
Beerbaron

[ronboskz650sr]

No it's not an electrical problem, still searching for the problem. Beerbaron

If your post is complete on what you've checked, you have not ruled out an electrical problem. Weak spark, for any reason, will also cause plug carbon fouling. Rich mixture is not the only cause. My bike runs very slightly lean, due to the epa rules in 79. When my battery gets weak, the plugs foul with carbon after about an hour, especially if I run high beam in traffic around town. After a quick charge and plug cleaning, the plugs check very slightly lean again.

[beerbaron]

Battery runs at 12.7 V and the alternator aroud 13 V @ 2000 RPM. I'll try to adjust the gap of my spark plugs... maybee that's it (I'm now reduced to try thgins I know won't work, lol )

BeerBaron