Running without back-pressure?

[KCvale]

agreed agreed, if you want PERFORMANCE from a two stroke, you get a well designed tuned pipe/expansion chamber. its simply a supercharger for 2 strokes.

I like to refer to them as a Reverse Super Charger, but the same meaning ;-}

if you only want to reduce noise, you stick on the stock standard exhaust as equipped.

Yep. and maybe a short muffler on the end of that.

if you couldnt care less and just want to get home, or around for a few days until parts arrive... remember that virtually no 2 stroke outboard engine runs a muffler...AT ALL! they actually run with negative back pressure, as the propwash is "sucking" on the standard exhaust outlet, ie, the middle of the prop.

no engine will be damaged by running with no exhaust system (look at the old aircraft...they had little 6 inch pipes only to clear the fuselage) AS LONG AS you tune the carb to suit. they just may not produce all the power they can....

Yep, you need to adjust the carb to let more fuel go right through and out the exhaust pipe.
It the case of outboard motors, they just dump that unburnt gas/oil mix right into the water.
Back in your time reference days gas had Lead in it too, yummy in the water supply, think Flint.

Of course you can get the best of both worlds...
An expansion chamber 'reverse super charger' AND an excellent muffler on the back end like this.

A tuned X pipe with an auto Glass Pack welded on the end.

Man I miss that bike, it was one of my first 1/2 dozen builds and my personal ride for more than year.
Fast (3-speed 66cc shifter), Quite (X-pipe with muffler) and Comfortable, (Front and Seat Post shocks).

Sorry, I digress, just a fond memory moment, I built that in 2010.

I am on the 4-stroke band wagon these days, they have valves so inherently more efficient and quieter to begin with, and much easier to quite down on the exhaust side without a performance loss on these small engines, which quite frankly, isn't much to start with so you take advantage of everything they have and that you can enhance to fit your need.

On a 2-stroke, X-pipes rule, watch any motocross event, not a SINGE BIKE runs a straight pipe.

 

[45u]

This is the pipe I will be running on build 2. Good chance I will have to put a silencer on it.

 

[butre]

the loudness on those pipes isn't too bad, you may not need a silencer. especially since you're used to working with harleys

 

[45u]

the loudness on those pipes isn't too bad, you may not need a silencer. especially since you're used to working with harleys

LOL My Harley for 116,000 plus miles has had good mufflers as I like to hear my stereo, CB and if I have a passenger the intercom. LOL but yes I do work on ones that are loud but not like years ago as with out any back pressure on Harley s they will not perform well on the street only WOT. I plain on trying it before I do anything to it.
Thanks
Jeff