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fooling spark plugs

Joined
Jul 31, 2001
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#1
I have a Honda cr250 2000 model, I keep fooling spark plugs
when I go to start the bike. Once I put a new plug in the
bike runs fine no problem. The next time I go to ride it
fools when I start the bike, then it takes a new plug to
ride it again. I bought a new air filter no help, and yes
I turn the choke off as soon as it starts. could it be the
rings need changing, jetting ( jetting is stock) I run 40:1
ratio on gas. HElP Please.
 
Joined
Oct 9, 2000
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#2
Wrong forum!
Well, the air filter is not really your problem unless it is dirty or overoiled.
The jetting is probably a factor
Spark plug heat range will do that too
A bad top end is not very good if you want your bike to run properly

There are ALOT of factors that can cause this problem and I need more problems to zero it in, such as, how does it run while riding it? Does it smoke or spooge alot? How much compression does it have? When was thelast time you did a top end?

Sorry to be so vague, but you need to be a little more specific.:)
 

MikeT

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#3
You mean "fouling"? You fouled a plug.

I'd run 32:1 and then clean the carb out. Remove all the jets and clean them all out. Try that for starters.
 

motometal

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#4
dirty jets would cause a lean condition, not plug fouling.

certain premix oils tend to cause fouling, you might try a different type of oil. I used to have problems with Maxima Super M, but I have been told the formula was changed...

also castor oil tends to foul plugs if the bike isn't run hard.
 

MikeT

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#5
Originally posted by motometal
dirty jets would cause a lean condition, not plug fouling.

True, maybe he has a weak spark. Enough to run but not burn everything...
 

wanrep

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Aug 21, 2001
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#6
Who's Fooling Who?

I once fooled a B8ES into thinking it was a B8HS by stacking washers underneith it.
Never had any luck fooling a plug into thinking it was a different heat range without it fooling (and fouling) me.
If you're fouling a "9" heat range, try an 8 or 7.

Don't ever try Butterball spark plugs.
They're really "fowl".;)
 

MikeT

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#7
Good one wanrep. ;)
 
Joined
Jul 25, 2001
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#8
I recently had a very similiar problem. After buying a used 2000 YZ 250 I rode it twice with no problems and it ran great. Before I was about to take the third ride the bike wouldn't start. I tried cleaning the plug but it wouldn't start. A new plug fixed the problem, but only temporarily. I consulted this forum and was told of several things to try. I also consulted my friend who has lots of experience. He simply said...it needs a smaller jet weathers different now. I bought a 168 (stock was 170) and now it runs perfectly. He also advised on getting several different sizes for different weather and riding conditions.

My advice...before you tear into the motor, or clean the carb, or anything major....try a smaller jet. It will likely fix your problem and if not you at least ruled it out and it only cost you a few $$.

I live very close to the coast so weather conditions change quite dramitically and it really amazed me how much of a difference that small change could make.

Good Luck.:cool: