Reed Chatter

[Ganno595]

Opti 175 Pro Xs. 1B698699 The reed chatter or "slap" seems just a bit louder to me on cold startup. Its always been like that just curious as to why. Is it just cold start harmonics or does oil coat them or what?

[JOE54]

def not reeds , do not rev it in neutral please

[lpugh]

reeds have virtually no sound that you can hear

[Ganno595]

I do not Rev it in neutral. I've read posts where Don said the fiber reeds do have some "slap" that observed at idle and mid range. So that's not true?

[Ganno595]

BTW... your reed cage lapping (and precise reed fitment) would also play a SUBSTANTIAL role in sound dampening.

Reed "slap" is a very common sound in the ProXS engines- and it's most noticeable at idle, and 3200-3800 RPM's.

Reed "slap" is the sound of reed petals "slapping" against the reed cage as they close, under crankcase pressure.

On these specific engines (primarily the ProXS/XS engines that utilize Carbon Fiber Reeds)- it is the "nature of the beast".



Quotes from Don

[JOE54]

wouldnt think temperature would change sound

[Ganno595]

I'm just drawing that conclusion from the way vehicles sound when first started to when they warm up a but.

[JOE54]

they do get lots of oil on um

[EuropeanAM]

It may be a bit more noticeable when cold due to a combination of the oil lubricating them being thicker, and the engine running significantly richer.

As the reeds age (especially where standoff begins to increase) the sound may become more notable.

Some are even loud enough that you can discern which cylinder it is during a misfire test... but that usually takes about .040"+ of standoff (well outside tolerances).