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Hesitation

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Just got back from the track/trails and my CRF230F was running abnormally. Sometimes when I would pop the throttle to hop over a log it would hesitate and I would end up running into the log instead of the front end hopping over it. It only happened a few times, but it hasn't done this before. I haven't ridden the bike for about four weeks if that is any indication as to what is happening. Haven't cleaned the air filter in a while either. Would a dirty filter cause this intermittent issue?

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Just got back from the track/trails and my CRF230F was running abnormally. Sometimes when I would pop the throttle to hop over a log it would hesitate and I would end up running into the log instead of the front end hopping over it. It only happened a few times, but it hasn't done this before. I haven't ridden the bike for about four weeks if that is any indication as to what is happening. Haven't cleaned the air filter in a while either. Would a dirty filter cause this intermittent issue?

 

 

Dirty filter.

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Just pulled my plug and it is black and saturated with fuel. My air filter was pretty dirty too. Would a dirty/restricted air filter cause the engine to run rich enough to foul a plug, or do I need to consider going with a slightly smaller main jet? I put a 120 main and 45 pilot in it, and am at 300 ft above sea level. BTW, I believe I adjusted my air/fuel screw when the air filter was dirty. Could I simply need to re-adjust?

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I set it at 1/2", but I'll check again. The float doesn't exactly sit flat so I just measured at the center with the carb on it's side. So you don't think a dirty filter would foul a plug? I haven't cleaned it in four months. And it's been running fine until recently, so how would the float bowl get out of adjustment?

Meant to ask, shoukd the spark plug gap be increased with the larger jets or left at the stock spacing?

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Just replaced the spark plug, no difference. Stumbles and almost dies when popping the throttle. FYI, the bike has not warmed up. I'm going riding tomorrow so we'll see how it goes. How often should I be cleaning the carb?

Edited by mossman77

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Come to think of it, maybe it has always done that and the only reason I am realizing it now is because it stumbled a couple times while riding, which has never happened, and now I'm paying closer attention. Apparently it is pretty common for a four stroke to do this. Now the soaked plug is another story.

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A properly-jetted CRF230 will never stumble.  Both of ours will take a big handful of throttle in third gear right off idle.  A dirty air filter acts just like a choke and will cause all circuits to meter rich.  The idle mixture screw has no impact on midrange and above throttle positions.  Spark plug color should be like a paper bag or slightly lighter.  If the plug is flat black you are too rich.  If the plug is shiny black you are pushing oil past the rings.

 

Spark plug gap should be between 0.030" and 0.040".  Generally speaking the bigger the better if the ignition can handle it.  All of ours are at 0.035".

Edited by VortecCPI
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Plug is shiny black. I figured it was fuel. If it is oil, wouldn't I see white smoke from the exhaust? Bike runs great otherwise and mostly only stumbles when popping the throttle at very low speeds (when hopping over obstacles in first gear), and doesn't happen every time.

The gap on the old plug was set to 0.04" and that's what I set the new one too as well.

FYI, I replaced the plug when I first bought the bike in May and it was white. This was likely the original 10 year old plug (at least 3 years old according to previous owner). Therefore, I think it is most likely the carb is in need of adjustment. I'll pull the plug today after riding and see what it looks like.

Edited by mossman77

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Plug is shiny black. I figured it was fuel. If it is oil, wouldn't I see white smoke from the exhaust?

 

No - Not necessarily.  Clean the air filter and check the float level.  If both of those are good then you have another problem.  Loose main jet maybe?

 

When you do a plug check you need to run the bike WOT on a level or slightly-inclined surface in at least fourth gear and then hit the kill switch with the clutch engaged. If you let the engine run at any other speed after the WOT run the plug read is useless.  This is why I prefer and recommend the Mikuni Roll-Off method instead.

Edited by VortecCPI

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so level surface, 4th gear, kill the engine, then look at the plug. I'll do that today.

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I pulled the plug after several hours of riding today and it is a light brown mushroom color, so it looks like I may be okay.

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But still, clean that air filter (choke), like every other rideicon1.png! You're gonna eat some expensive dirt!!!

 

Yes, of course.  I cleaned it real well before my trip.  Running like a champ.

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