It could be that your carb float is too high...look up float adjustment in your manual..Or maybe a weak spark from the coil, try and sand down the coil grounds on the frame that might help..Also it could be that you are running too cold a plug.I ran 40:1 with Yamahalube-2R in my 94 CR250 .What size, year and model is your bike??? Let me know and maybe I can give you some more info..Good luck!!!

 

Many variables there bro...
Try running a different type of standard oil at like 32:1 and check your results.
I have heard that pure synthetics can be run much leaner.
Do the plugs foul right away or after a period of time?
Are you using the reccomended plug?
What kind of iding do you do?...Is slow tight trail stuff or open course type mx stuff?
Start with a new properly gapped correrct type spark plug. Find a straight away and crank down it opened up in 3rd gear.( please be careful though) Then pull in the clutch,leave the throtle pinned, and cut the engine with the kill switch. Pull the plug and check the color. Light tan is a good mix...sooty and black is a rich mix. Lean and rich meaning fuel to air not oil and fuel.
What kind of bike??
When was the last time you cleaned the carb?
Is the top end frin good condition?
Is your air filter cleaned and properly oiled?
How is the power output in general?
Let us know..we want to help.
Good Luck!!

 

plugs foul for many reasons...
first off...I will tell anyone and everyone that synthetic oil is not all that it is bragged to be...I tried running it a few times and had nothing but problems with plugs fouling out and carboning up...I would recommend running 32:1 with yamalube 2R....
check the plug and put a fresh plug in...making sure that it is the correct temp plug...

a thing about fouling...
if you ride in idle mode alot, they tend to carbon up or "foul out"

explain to me what exactly you mean by fouling out...is it just wet...or is it getting carbon build up??

dirty carbs will affect your fuel:air ratio...and fuelil mix will affect plug life...
as Wiseguy explained there are alot of variables as far as what can cause it..but the more specific you are the btter and more precise the answers will be...
air filter is another thing to check...

give us more info!!!


AirBorn!!
The good Lord giveth and the Eco-Nazi's Taketh away!
United we stand..Divided we fall..LETS UNITE!

 

I'm sorry that I wasn't more specific... but what I was hoping for was a very general answer. I had read these boards numerous times and came to realize that fouling a plug was not a direct result of your oil/fuel ratio, but the plug fouling is due to excessive fuel in the fuel/air ratio. Not excessive oil in the fuel/oil ratio.
This is where the confusion started for me. I went to my local bike store in which I had high regards for for their knowledge and the parts guy said that a fouled plug was a direct result of to much oil in your fuel. He actually smirked when I said I run 32:1 with bel ray and wondered why I wasn't fouling plugs left and right. I had been going to this shop ever since I started riding and came to believe that they all actually knew what they were talking about.
This is why I asked you the question about a fouled plug, it was not meant to be "why am I fouling" but the direct cause of it. When I walked out of that shop I was actually believing that parts guy about plug fouling. Thats why I posted that question here... to find out the real answer and to tell that guy he doesn't know sh*t and shouldn't be talking about things that he doesn't even understand.

 

but again do you mean fouling out in a true sense or carboning...this is a defenite difference...
carboning up IS directly related to fuelil Mixtures....


AirBorn!!
The good Lord giveth and the Eco-Nazi's Taketh away!
United we stand..Divided we fall..LETS UNITE!

 

Its interesting that you bring that up because I do believe I am having a carbon fouling problem. I had previously thought it was an oil fouling problem but after looking at numerous pictures of different examples I figured it was a carbon problem.
Heres my specs, hopefully you can help me out.
The type of bike I have is a 96 KX250
I am carbon my plugs in what seems to be every 2nd or 3rd time out riding my bike. I clean my air filter after every 3rd ride. I did use redline oil at a 40:1 ratio then I switched to bel ray recently and run that at 32:1. I run pump gas at 92 octane. I ride mostly on trails and hardly ever on a mx track so I do go very slow fairly often. I am running the stock jetting with the pilot needle on the 4th groove so it runs a little leaner. I also set the bike so that it would not idle. I have checked the reeds to see if that was a problem or not but they seem in really good condition.
I did clean my carb completely about a month or 2 ago, but I still had the carbon fouling problems. It seems to me that I clean my air filter and change my gear oil and the bike runs perfect. I ride it the next day or following week and the bike is still running perfect. It seems like the third week I take my bike out it will foul a plug. Each time I go out riding its for about 3-5 hours a day.
Could it be that I just need to clean my air filter more frequently. The places that I ride in is always very dusty.
I am also using the spark arrestor that the guy who sold it to me had, it seems really old. Its a Answer Spark Arrestor. I have read about silencer repacking but I wasnt sure if this applied to this filter. I tried to take it apart but there were 2 rivets that would not come out so I figured that it wasnt an option.

 

Some may say I'm crazy, but I change my oil and clean my filter after every day of riding (especially the filter, dirty filters do horrible things to carbs and cylinder walls). Oil is cheap, so is filter treatment.

RoosteR
I love the smell of two-stroke in the morning.....

 

ok first thing...change ONE thing at a time...too many changes can do adverse things...
change your oil every third ride and clean the filter EVERY time you take it out...
dirty oil filters as roosteryz13 stated can do nasty things...
it will affect the way a bike runs also...
second, try using yamalube 2-R or AMSoil...run it 32:1 and run middle gasoline...what plug are you running? It sounds like you may possibly be running a plug one step too cold...try stepping the plug up one heat number.

Next thing, I do alot of trail riding too, and depending on the trails riding techniques, will determine how it carbons up...when you are in the trails and cruising...say fourth gear...and it is running but it is not in the power band...then put it in third and run it right on that edge...it will clean things up a bit more then usual...
not being able to repack the silencer is a bit strange though...maybe pop the rivets and replace them with sheetmetal screws so you can repack it regularly...



AirBorn!!
The good Lord giveth and the Eco-Nazi's Taketh away!
United we stand..Divided we fall..LETS UNITE!

 

This friday I'm gonna go get me a new FMF Turbine Core 2 filter, my old one is lookin poopy.
As for the plug I'm using its a NGK BR8EVX, its the stock plug that my clymer book recommends. I was thinking of going a step hotter to see if it would fix my problem, but I thought I'd try getting a new spark arrestor and try cleaning my filter after every ride to see how it works.

 

that actually sounds good...
pick up a hotter plug and bring it with you on the next ride...that way you will have a back up plug, and can work/play at the same time....


AirBorn!!
The good Lord giveth and the Eco-Nazi's Taketh away!
United we stand..Divided we fall..LETS UNITE!

 

Airborn - just curious as to what adverse effects in changing the oil after every ride? I'm not doubting you, I just have always done it after each ride.

RoosteR
I love the smell of two-stroke in the morning.....

 

Hi...
I have had a problem with my plugs a couple of months ago.
I literally had to change my plugs every 1/2 hr...
So I did the first thing.... I double checked my oil/gas mix...
I set is to a PERFECT 32:1
The problem kept on ... So I reduced my mixture in the Carb to have a leaner jet.
Well that did not work....So finally I had ruled out 2 of the most common causes...
I finally took my silencer apart... It was clogged with Liquid and all kinds of crap...
In the end I had backed up Exhaust ruining my plugs.... I ultimately changed the silencer
and never had the problem since ...
I Have been running on the same plug for about 3 months now

Hope that helped you.
Ride safely

 

I do my oil after every other ride...just because I can not afford to do it after every ride....and sometimes I question why you would change it every ride...a car can run on the same oil for 3000 miles...and it gets beat 10 times what a bike does...and the tranny fluid is every 50-100,000 miles...get my drift???
I go about every 2-3 rides...thus I am not abusing the machine but not abusing my pocket book either...I also run expensive oil...not just the elcheapo ****t...


AirBorn!!
The good Lord giveth and the Eco-Nazi's Taketh away!
United we stand..Divided we fall..LETS UNITE!

 

What oil do you run? I do know wha you mean about the pocketbook thing though. Tha's part of why I change my oil so much, the thought of having to split the case on a brand new bike really freaks me out!

RoosteR
I love the smell of two-stroke in the morning.....

 

yamalube usually...I use all yamalube in my rides...Either that or AMSoil...
that is about it...


AirBorn!!
The good Lord giveth and the Eco-Nazi's Taketh away!
United we stand..Divided we fall..LETS UNITE!