You can't without extensive modifications, adding counter balancers, etc. The cheapest way is to isolate the vibration by mounting the engine on rubber bushings. Place the bushings between the engine and the and the mounting surface - like big rubber washers.
Increased vibration leads to increased component wear, heat, and stress. Also, the less vibration, the more pleasant the car is to drive.
A quality engine oil will help to reduce engine friction .
To reduce compression in an internal combustion engine you should change the standard pistons for a more flatter piston, which will increase the combustion chamber size, some people also change the standard head gasket for a slightly thicker one.
If petrol mixes with engine oil in a 4 stroke engine then the mixture becomes thick and its combustion will not be efficient. The exhaust will be smoky due to this incomplete combustion. also this will reduce engine efficiency.
High Octane fuel is highly refined fuel which is often used by the aircrafts and jet airliners. Therefore, such fuel will definitely help you to lower down the engine vibration.
The amount of ozone in the air we breathe can be reduced by avoiding / minmizing processes that use internal combustion.
buy a 2004 sportster..it has a rubber mounted engine that isolates vibration
The best way would be to keep your fuel system clean, keep air filter clean, always keep your o2 sensors in good condition, and make sure your catylytic converter is in good condition
organize you combustion chamber with carbohydrate rods and put friction pumps in the engine
starting with the redesigned 1998 altima the engine crankshaft was balanced much better to reduce vibration. we have a 1993 and a 1999 altima with the same engine and the 1999 is so smooth at idle i sometimes can't tell if it's running.
You can change the air-to-fuel ratio to get less optimal combustion.
Reduce the vibration and protect the machines.