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Old 04-19-2010, 04:09 AM
Fabian Fabian is offline
Join Date: Sep 2009
Location: Australia - Melbourne
Posts: 168
Default Re: Does installing an extended exhaust keep our clothes from smelling?

What gets missed in these "oil debates" is the fact that 2-stroke oil (especially in an air cooled engine) serves two purposes: firstly as a lubricant, but secondly as a piston ring sealant.

The second function is almost always understated or dismissed.
In an air cooled engine with minimal amounts of air flow, bore distortion becomes a significant issue, particularly on the exhaust side.
This is where 20:1 plays an important part in preventing or reducing blowby.

A third aspect that oil plays in this scenario is heat extraction.
An air cooled engine has a fixed amount of cooling surfaces - the only way to manage localised hot spots is by means of thermal transfer to oil, as it's the only parameter that can be changed to suit conditions.
More oil = greater heat extraction, with a suitable jetting change.

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