Traxxas 3.3 backfiring out of exhaust

A tune-up is always a good idea. Is the system running rich or lean? Any applicable trouble codes? Is it back firing out the exhaust? If so, I got two thoughts, either an exhaust system problem or exhaust valves?

Preventing Backfire on Motorcycle Exhausts ' DoItYourself ...

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When the engine on your motorcycle has an emission system malfunction, such as anexhaust leak or a moment of running rich or running lean, backfire can ...

Exhaust backfire, popping when letting off throttle - Motorcycle Forum

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Apr 26, 2009 - 28 posts - ‎17 authors
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Jun 12, 2010 - A visible flame may momentarily shoot out of the exhaust pipe. ...Another backfire situation occurs when the engine is running rich, meaning ...

Is backfire when decelerating a bad thing? : motorcycles

backfire is a timing issue ,if its to far advanced it will back fire out intake ,if it backfires out exhaust its to far retarted ,you may have a bad timing gear,and or chain or belt, start by checking timing if you can get it running infact go over ignition system to look for other problems

Make/Model/Year/Engine size, these are helpful for a more precise answer.
However, you are describing a backfire problem that occurs when the engine is placed under a load.

The major contributors to backfire under a load (and in general) are:
1.Bad fuel
2.Weak Spark
3.Poor Timing
4.Poor seal due to valve considerations (adjustment and wear).

So here are the fixes:

1. Check for good spark and replace the plugs. UN-burnt fuel, due to weak spark, causes backfire in the exhaust.
2. Weak spark may be due to coil problems or bad coil gap. Check coil gap.
3. Change fuel to the highest octane you can buy. Old fuel looses octane and does not burn as hot. Do not store fuel for more than 3 months.
4. If your engine has a flywheel key, it may be damaged. This will throw off the timing.
5. Check the valve adjustment. A sticky, bent, or worn valve can cause backfire. Worst case you may have to do a valve job (have the valves and seats reground).

These are your first line, mostly easy, fixes for backfire.

Incorrect static timing, severe misfire, bad ECU, severe contaminants in the gasoline (especially vandalism with sugar or palm kernel oil), or any number of engine position sensor failures. Normally, only vehicles that have been very poorly maintained will ever backfire unless one of the causes listed above is present. A backfire is a symptom of a serious problem and the car should not be driven at all until the cause of the backfire is found, so that the engine is not permanently damaged (unless it has already been destroyed).

Go to the Traxxas website. A thumbs up would be greatly appreciated if answer is helpful for your question. THANK you and GOD BLESS

If you have not replaced plugs start there A bad map sensor will also cause black smoke and poor running

If it is back firing through the exhaust, it is not running good because you are putting unburned fuel into the exhaust, bad spark plug or leaking exhaust valve, you need a compression test to start, you may as well change the spark plugs while they are out

Backfiring can be caused by fouled spark plugs (you have four,two per cylinder), bad spark plug caps, bad air cut valves on the side of the carburetors, but most likely leaking exhaust gaskets. I am guessing that you have changed the exhaust system but did not put new crush o-rings between the cylinder head and the head pipe. You should also change the tubular gasket/seals between the head pipes and the mufflers. If this does not fix the problem , take out the two screws that hold the air cut diaphragms in place and remove the covers . If the rubber diaphragms have holes in them or have become sticky they need to be replaced. Air cut diaphragms turn off the fuel during deceleration to prevent back firing. If they go bad they can cause poor running , popping , and back firing during normal operation.

check the air intake or manifolds gasket /seal