Running 2 stroke without muffler

[blackknight2345]

Wanted to run a 30cc 2-stroke to max rpm without stock muffler attached. Is it safe?

[ticedoff8]

Originally Posted by blackknight2345

Wanted to run a 30cc 2-stroke to max rpm without stock muffler attached. Is it safe?

This is a weird question.
What are you specifically worried about?

I'm guessing this is a gasser (gasoline) 2-stroker and I would suggest that with or without a muffler (stock or otherwise), running a motor at max RPM isn't a good idea.

But the word "safe" leads to a bunch of other questions

[blackknight2345]

I am specifically worried about dirt ingestion taking place at the exhaust port and consequently damaging the components. The RPM I aim to run the motor at isn't the max RPM, my bad, I wanted to run it at around 10500 RPM to 11000 RPM.

[ticedoff8]

Originally Posted by blackknight2345

I am specifically worried about dirt ingestion taking place at the exhaust port and consequently damaging the components. The RPM I aim to run the motor at isn't the max RPM, my bad, I wanted to run it at around 10500 RPM to 11000 RPM.

Dirt ingestion would be through the carb, not the exhaust.
Assuming the engine is running, there is no chance dirt could enter through the exhaust header.

And, once it is more than a meter above the ground, dirt is no longer a concern

[blackknight2345]

I am using a Zenoah g320 and with its stock muffler, it doesn't have a header, the exhaust port is exposed from the cylinder body directly to the atmosphere. Can the dust enter through such short lengths of the exhaust outlet?

[Andy from Sandy]

If it is 2 stroke, no valves it may not even run without an exhaust fitted. They generally rely on the exhaust to stop the incoming fuel from just leaving the exhaust port.

Even 4 strokes rely on the exhaust. An old motorcycle I had I couldn't get started without one fitted.

[wjvail]

Short answer: You can safely run your engine without a muffler.

Longer answer: You can safely run your engine without a muffler but, you will not be popular with the neighbors.

[ticedoff8]

Originally Posted by blackknight2345

I am using a Zenoah g320 and with its stock muffler, it doesn't have a header, the exhaust port is exposed from the cylinder body directly to the atmosphere. Can the dust enter through such short lengths of the exhaust outlet?

Assuming the engine runs without a muffler (I agree with the comments questioning this), once the engine is fired up there is nothing that will enter the engine through the exhaust port.
The velocity and volume of the exhaust gasses would be too great to allow contaminates (like dirt or small bugs) into the cylinder.

However, other "bad things" may happen unrelated to dirt.
If the manufacturer of the motor recommends a muffler, your best bet (overall) is to use it. If there are problems with the motor starting, idling, attaining full power, it may be related to the lack of a muffler

[wjvail]

Chainsaw guys routinely run their saws with virtually no muffler. They think they need it for faster cutting.

Also, any time you make substantive changes to a motor, it is possible (likely) you will have to retune it for best performance.

Really though, running it without a muffler is a bad idea. The ridiculous ear-shattering sound makes any possible benefit meaningless.

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[hirobonathan]

It will run fine but for what reason is beyond me. Each to there own and good luck with your neighbours or people around.

Also be careful with what state you are in due to 2 stroke engine laws. These day you need to be running a muffler with a 'spark arrestor screen'. Basically a tiny mesh screen on your muffler that stops combustion sparks shooting straight out of the muffler and into the ground starting a fire. Usually a huge no no for chainsaw operators, leaf blowers and weed eaters due to fire risk