My 2000 SP500 started running real bad the other day, stalling and idling rough. I pulled the plug and it was black. I bought a new split fire, didn't help. After talking to Greg, I removed the muffler to see if any mud was in it and removed the carb to spray some cleaner in it and at the choke. Nothing improved at all. The muffler seemed to be clean and the same with the carb. I sprayed it anyway but none of this helped. One dealer told me that it may need to be re-jetted, the dealer that I bought it at doesn't think so. It's still under warranty but it is very difficult for me to get it to the dealer. Any ideas?
Rick

 

Did you try the air filter, Put in a new one if you run stock, of clean it if its K&N, or foam
good luck

WJW

 

Sorry but I disagree with the dirty air filter.

A dirty air filter causes a slow loss of performance over a period of time. Not all of a sudden things turn for a crap. A dirty air filter can cause all or some of the following symptoms: oil foulded plug, loss of power, poor throttle response, excessive smoke, increased fuel consumption and I am sure a few others.

If you have the sort of engine performance you are describing it would make sense to me to have a closer look at the fuel delivery. Start at the fuel tank and go right to the main jet. There is a possiblitiy that there is a foreign particle of some sort plugging up an oriface in the carb. Removing a nd cleaning the carb throughly could be the solution. I can't guarantee it but it is worth
considering.

Anyone have any comments or other ideas?

Keith

 

I know I am talking 2 strokes but,my wifes explorer 250 was running great .Well one we took it riding & just like you flipped a switch it was
bogging & had a severe power loss.I first thought
2 stroke must have a fauled plug,changed it seemed
to run a little better but not fixed.After checking more I found a partly clogged prefilter,
runs great again now.


TRUCK

 

I agree with the air filter theory. My buddies 99 SP500 whent from running fine to bairly running in about 2 miles! His prefilter was plugged up in just 2 miles of riding behind me in really dusty conditions.

 

Just wanted to get to the top of the page so people would check it out and maybe get more ideas. :0)
Rick

 

Just wanted to thank every one for helping out with this. I got the bike up and running today. The same way it was before it started. Anyone want to guess what the cause was????
Rick

ps. after I get enough guesses, I'll post the answer.

 

If guesses are free, I guess I will make one:

Since you cleaned the carb and checked the spark plug and it was black, it must have been running rich. I am guessing dirty air filter or the choke was stuck on.

 

sorry not the correct one
a little hint....it had to do with the carb
Rick

 

You found that a mouse had built it's nest in your
air box?