kx250 wont run, still has spark

[jetpilot773]

ive messed with this thing for tha past week or 2. i just got a new plug for it and the thing ran for about 20 minutes then it died like the plug was fouled or somthing. i got the plug cleaned off and it has good spark to it. i changed the gas completely and got some better oil for it and leaned it out a bit. the same exact thing happened again! the plug didnt look oily but had a dry dark black color to it. ive replaced most of the hoses on the bike and know gas is getting to the motor. could the coil possibly be bad??? (plug not getting hot enough) im running out of ideas. oil is castor 927. running at about 40:1 on 89 octane gas.

 

[trial_07]

Try 32:1. For the spark plug, I came across a good thread in which Rich clearly explained how to read plugs. You might want to search for this post.

 

[trial_07]

Here it is:

http://www.dirtrider.net/forums3/showthread.php?t=92818&