• 2009 rancher 420 Bike will crank and idle about 10secs then start surging and...

    2009 rancher 420. Bike will crank and idle about 10secs then start surging and die. Will crank back up with throttle applied. But die again. If you hold at quater throttle it will run for about 45 secs choke down backfire real loud and die. Will crank back up. Bike has new fuel pump, injector, clean tank and throttle body, fresh had, new plus. Valves are not tight, start button does seem to be stiff but starter doesn't hang up. Bike has been used for hunting it'd whole life. I'm about out of idea. Battery is hot.

    10 comments
    • Cleaned or changed the Idler air control valve?

    • Yeap. It's spotless and working properly best I can tell.

    • Had one was doing the exact same thing it was one of the sensors on the air box we switched out the air box with a spare we had and no other issues

    • We went through everything even changed the ecms and just out of nowhere we decided to change the air box don't know which sensor it was though when it started running right we left it alone lol

    • I uploaded a video don't know if it worked. Just changed airbox sensor and same thing.

    • Have you checked the fuel pump relay?

    • Restriction in the exhaust ?

    • Honestly hasn't even crossed my mind.

    • Might be the problem

    • Throttle position sensor