David,
Airbox design can be crucial in performance tuning any engine, not just
2 stroke motorcycle applications. The job of the airbox is to contain
the filter element, as well as control flow of a calculated amount of
that clean air to the intake of the carb. Generally, a specific air/fuel
mixture ratio is desirable to meet tuning peramters set by the
designers. These perameters also factor in intake type( rotary, reed, or
piston port in 2 strokes), intake tract length and diameter, number of
valves and actuation type in 4 strokes, as well as piston type and
cumbustion chamber shape, and exhaust system length, shape, and type.
In street legal applications, of course, emissions control constraints
factor greatly. A common ratio is about 14.5:1 parts air to fuel. This
of course varies with engine application, type (2 or 4 stroke, or
diesel), state of tune etc..
There are some good 2 stroke tuning and design books out, printed in
England, and sold thru a variety of sources. Sorry, but I am drawing a
blank on the author at the moment. Check for ads in Cycle News or
American Roadracing, and I think I may have seen one of them in the
Transportation section of a Borders Books store a while back.
Good Luck and Happy Holidays.
Mark
Scorpa 295 Works
David F. Allen wrote:

> I have a question in regard to air box design and the impact it has on
> the
> performance of 2 stroke motors, particularly trials bikes.
> Can somebody explain the function of the air box and if indeed it
> impacts
> the power output.
> I know I should read some books on 2 stroke tuning - Any good
> recommendations?
> Thanks for any help
> Dave