Can someone explain how or when the power jet on my 03 YZ 250 works? In a diagram the manual indicates this jet can have an effect from fully closed to 1/2 throttle, but notes: that it closes at 8,500 rpm. Then states "the richness of air-fuel mixture under 8,500 rpm to the extent of 1/2 to full opened throttle can be set by changeing the power jet". I'm so confused please help.
Ok my KX has one. I'll try to explain. It is a fuel circuit that is controled by the ignition system, when there is power to the powerjet it is closed leaning out the jetting for more overrev, when there is no power to the powerjet it is open and fuel flows through the circuit making it richer for a stronger midrange. The ignition uses the RPM and the throttle position sensorto control the opening and closing of the powerjet solenoid. If you unplug the power jet solenoid the bike will be rich at high RPM but should run good everywhere else. Hope this helps. Ed
Ok, then is the solenoid simply open from idle to 8,500 rpm? or does the throttle position sensor dictate when the solenoid opens, say like at 1/4 throttle or what?
Pretty much yes but it adds fuel by being turned off, no electrical power to it, then a around 8500 power is sent to it closing the fuel off. The idea is to get a strong midrange with a good overrun.