What makes Big Bear 400 Hi idle and backfires while running?

02 Big Bear 400- Hi-idle & backfires while running. Tried cleaning carb & air filter, drained bowl & cleaned with carb cleaner. Could there be aproblem with the choke. Clicking this will make more experts see the question and we will remind you when it gets answered.

What happens when you adjust the carburetor on a Big Bear?

Any adjustments made to a cold engine may cause the idle speed to increase beyond the specified 1,450 to 1,550 rpm range; this can make it difficult to shift gears and cause the engine to race at idle. Do not turn the pilot air screw counterclockwise more than 4 1/2 full turns from its seated position.

Is the warrior Idles fine when trying to accelerate?

The warrior idles fine. I’ve adjusted to air mix screw back and forth. It changes the idol but doesn’t seem to improve things when I try to rev it up. 2.25 turns seems to be the sweet spot, as far as idol. The needle is where zoom put it.

Where is the pilot air screw on a Yamaha Big Bear?

Turn the pilot air screw — located on the bottom of the carburetor and directly below the engine intake flange — clockwise with a flat-head screwdriver until it is lightly seated. Count and record the amount of turns needed to seat the screw. Ideally, the screw should take 2 1/2 turns to seat.

What does it mean when a car starts and idles?

It starts and idles like it is brand new. You can start to rev it up and o ce it hits a certain RPM it hangs there and backfires/sputters/pops/bangs/throws fire out the pipe. I pulled the plug and it was BLACK.

What to do if your car starts and idles but then backfires?

Keep in mind, that if the reverse limiter is being turned on intermittently by vibration at the connection, the RPM that it settles to may be higher than if the limiter were on continuously. I’d suggest grounding the wire and riding, to see if the issue has gone away.

What’s the spark plug on a Big Bear 400?

He replaced the stator and primary coil also known as pulser coil or exciter coil or rotational etc., as well as the CDI, secondary coil (the one attached to the spark plug wire) along with the wire and plug. Still no spark. He dropped it off at my place a month ago to see if I could figure out what was wrong.

What to do if your Big Bear has no spark?

If you have the body off the front of the machine unplug the tires wires from the stater switch to the starter solenoid, jump the wires and see if the starter goes. You have been busy. The red wire at the CDI was power on the Big Bear but it sounds like you have power there so its good.

What was the last time my car backfired?

The last time I tried to start it, it backfired through the exhaust! With various carb issues in the past i have been able to get some kind of a different result by cupping the intake tube with my hand, while trying to start it.

Why does my Yamaha Big Bear not start?

If you have a hot spark (bright blue, because a poor spark can cause a fouled blackened plug), you likely have a carburetor leaking past the float valve. It’s a simple fix and I would replace the float and float valve as well.

What to do when your big bear won’t start?

If you’re getting hot spark you can assume you have a good signal generator/CDI on it. That leaves the carburetor which is probably flooding. Try purging the engine of gas by shutting off the fuel from tank and if you can drain the carb bowl. Then pull the plug and spin it over with full throttle. Try to start it with half throttle and no choke.

What causes a spark plug to backfire on an ATV?

Backfiring occurs when one (or more) spark plug in the ATV engine ignites the fuel when it’s out of turn in the chamber, and the exhaust valve on the cylinder is open. In other words, ATV backfiring occurs due to a short, sudden instance when the engine is too lean or too rich.

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