Espen's Reed Valves

[Bruce Plecan]

Please don't confuse operating rpm of the engine with the effective range of
the reeds.  The Yamhahaha, I mention was a 10,500 shift point engine.  But,
at any engine speed over about 2,000 rpm you could see the stand off in the
intake tract meaning the reeds had "blown" open.
   Yes reeds can "vibrate" at high frequencies (just look at a clarinet),
but that doesn't mean that as a check valve they will actually perform that
way.
Grumpy

> Crank case pre compression on a two stroke wouldn't work very well if the
> reeds stayed open.
> The key to performance at high RPMs is low weight, high stiffness and the
> proper shape. To get performance at low RPMs also, Boyesen's multi stage
> reeds can be used.
> Remember that 2000RPM is only 33Hz. Locking open at that frequency sounds
> improbable. 20,000RPM, sound more like it.
> Composite reeds, often using graphite, work well into the 9000's on
> outboards. The problem with composite reeds is that they don't last very
> long, however, the failure is not very dramatic. Metallic reeds, on the
other
> hand, while long lasting, will tear an engine to pieces if they break at
an
> inopportune moment.
> Maximizing reed cage area is important since larger reeds will give better
flow.
> Now, anyone for a homegrown EFI system for 2-stroke outboard ?
> Regards,
> John Hornkvist