2002 Prairie 650, no lights no limp mode and 4x4 works perfect.

Here’s the story.

I have been working on this for a few weeks now and cannot figure out what the issue is. When cold it will start with the choke just fine and after a few seconds I turn the choke off and it idles fine. I’ll ride it for around 5 to 10 minutes and then at a point, it will start to backfire and pop through the carbs to which it will die but start back up with choke and throttle fully down, but won’t take any extra throttle and will just idle once it started. Sometimes, after letting it idle for a few minutes, it will go back to normal and start the cycle all over again and sometimes it will just be angry until it’s cold again.

I checked the valve lash and it is in in spec, I have cleaned the carbs twice, flushed the fuel tank a couple times since there was some old stuff in there, replaced the boots that go from the carbs to the motor and the coils tested in spec and the same exact resistance, (can’t remember the exact numbers) switched them anyways and it still does it.

Now for interesting things that I’m hoping to get clarification on as well. If while it is idling and it’s “angry” state if I pull the plug to the rear cylinder it will die. If I pull the plug to the front cylinder, it will change the idle a tiny bit, but sounds pretty much the same. When I had just barely gotten the quad Both cylinders had 30 psi of compression when dry and 90 when oil was put in the cylinder and Just tested now and it’s the same result. I’m assuming this is because of a decompression mechanism but 30 seems so low.

Sorry for the long story but anything helps, in the mean time I will be checking every connection.

Thanks

 

I don't know that model at all but most auto decompressor equipped quads have over 90psi compression so I suspect your engine is in need of a rebuild. Also not sure how the ignition system works on your machine but it may be an ignition component on the front cylinder breaks down when hot. Trigger coils on the stator get hot quickly and are the usual cause of this, but CDI/ignitor or ignition coils can be the cause. I assume you have changed the plugs.

 

That seem low compression also I would check charging system and battery but Like merryman said low compression is low and ignition seems like has an bad component