spark plug

yamaha189
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yamaha189
Edited Date/Time 1/27/2012 12:04am
This may sound like a dumb question, but im new to motocross so cut me some slack. I was just wondering what different ways there were to clean spark plugs in between rides. im on a 2004 yz 125
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mx5471
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mx5471 7/19/2011 4:11pm
7/19/2011 4:11pm Edited Date/Time 7/19/2011 4:21pm
You don't need to clean the plug at all. If the bike is properly tuned,the plug will last a long time. Just keep a couple spares in the toolbox with you. I've had new ones not even fire,so more than 1 spare is good. If the plug is fouling,1 of 2 things is happening. You say you are new to riding. A 2 stroke motor, be it an outboard motor on a boat or an mx bike likes to be reamed. Otherwise oil builds up on the plug and fouls it. I've cruised in a boat with an outboard in a river that had no wake speed for miles. If you didn't ream that motor after, it's not starting. If your having a problem with plugs fouling and your not an experienced rider, try to find a long straight spot where you can run it flat out in a lower gear a couple times. That will help to clean the plug. If you have oil or black residue at the end of your silencer it means, first, the motor isn't running hard enough, or second it's just running too rich. The other thing is that the bike isn't tuned properly. Rich will turn the plug black and render it useless. Best advise is what I said above. As you gain experience and ride better, the problem will go away.
yamaha189
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yamaha189 7/19/2011 4:22pm
7/19/2011 4:22pm
thanks, the plug is black and a little wet around the threads so i guess it is running rich. i run a mixture of 40:1. do you suggest changing the mixture? and if so what to? also i'll try to go and ride sometime this week and do what you mentioned.
SteveS
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SteveS 7/19/2011 4:27pm
7/19/2011 4:27pm
The mixture of oil to fuel is correct--the manufacturer recommends 32:1.

The fouled plug is coming from either too-rich jetting, or from riding around blipping the throttle and going slow.

If you can't ride fast yet, then rejetting leaner is one way to deal with it. My guess is that you could actually just get the bike jetted correctly and then it will be better.
yamaha189
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yamaha189 7/19/2011 4:33pm
7/19/2011 4:33pm
thanks for your input guys, im just a newbie to motocross engines and such. just trying to accumulate my knowledge base. so i can actually start working on my own bike and not have to take it to my local shop everytime something goes wrong.

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project racer 7/19/2011 5:30pm
7/19/2011 5:30pm Edited Date/Time 7/19/2011 5:31pm
Raise the clip on the needle one notch , lowereing the needle. That will help clean up the low end richness without spending a dime. Also check the air screw adjustment, make sure the air filter is clean, and not over oiled.
MOTODAD422
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MOTODAD422 7/22/2011 9:44pm
7/22/2011 9:44pm
Top ends that are in need of replacement [low compression] will foul plugs.
yamaha189
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yamaha189 7/23/2011 5:44am
7/23/2011 5:44am
MOTODAD422 wrote:
Top ends that are in need of replacement [low compression] will foul plugs.
only have 2 hours on a fresh top end
dak
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dak 7/23/2011 7:53am
7/23/2011 7:53am
mx5471 wrote:
You don't need to clean the plug at all. If the bike is properly tuned,the plug will last a long time. Just keep a couple spares...
You don't need to clean the plug at all. If the bike is properly tuned,the plug will last a long time. Just keep a couple spares in the toolbox with you. I've had new ones not even fire,so more than 1 spare is good. If the plug is fouling,1 of 2 things is happening. You say you are new to riding. A 2 stroke motor, be it an outboard motor on a boat or an mx bike likes to be reamed. Otherwise oil builds up on the plug and fouls it. I've cruised in a boat with an outboard in a river that had no wake speed for miles. If you didn't ream that motor after, it's not starting. If your having a problem with plugs fouling and your not an experienced rider, try to find a long straight spot where you can run it flat out in a lower gear a couple times. That will help to clean the plug. If you have oil or black residue at the end of your silencer it means, first, the motor isn't running hard enough, or second it's just running too rich. The other thing is that the bike isn't tuned properly. Rich will turn the plug black and render it useless. Best advise is what I said above. As you gain experience and ride better, the problem will go away.
I have that black stuff coming out of my silencer too. i run 32:1 and i dont blip around all the time so im not sure whats happening. Im currently redoing my top end and there was alot of carbon build up on my exaust flaps but im not sure if that could of caused the black oily stuff.
SteveS
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SteveS 7/23/2011 8:12am
7/23/2011 8:12am
That black stuff is called spooge. A little of it doesn't really hurt anything--you're supposed to wash your bike every time anyway.

It generally means that your jetting is too rich. Or any of the myriad other things which have the same net effect.

Do your top end, clean the carb, then go through and jet the carb properly. If you're riding with the bike revved out on the pipe, you'll have minimal spooging. On the other hand, lean the jetting out too much and you'll burn a piston.
MX Dad #27 7/23/2011 9:22am
7/23/2011 9:22am
Start by jetting with a hotter plug.

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