Crankcase vent using a reed valve.

[ckahleer]

Why would this be better than a PCV valve?

 

[5twins]

You don't want to use a PCV valve because they don't (can't) react fast enough to the engine pressure pulses. They'll just stick open or closed so basically, they don't work for this application.

 

[Mikey]

View attachment 206546
https://www.mikesxs.net/yamaha-xs650-reed-type-engine-breather-valve-pcv.html
Your probably know of this simple solution, the MikesXS reed breather. I've been running one of these for probably 10 years, and am satisfied. I use it the same way people use the Dorman Power Brake Check Valve, I.E. attached to the engine breather outlet with a hose, and pointed at my air filter element.
From the site:

Reed type Positive Crankcase Ventilation Valve. Valve hooks to engine top breather vent and allows expelled air out but reed prevents air re-entering quickly so a very small vacuum is created in the crankcase.

Part of the installation direction
First, drill a 1.5mm safety hole inside ( Figure 1 ) why ?

 

[gggGary]

Part of the installation dorection
First, drill a 1.5mm safety hole inside ( Figure 1 ) why ?

Hi, I recently bought one of these reed valve breathers from Heiden Tuning. There are no fitting instructions and I cannot get a reply to questions re fitting. There seem to be two versions, early and late. I see you recommend drilling out an oil drain hole with pics of the early version. Does this apply to the later version please? On the later version the screws have tamper-proof markings and are very tight which implies it Is not intended to be opended up. Can you help please? Robert
3
Sam White on October 2, 2020 at 8:32 am Reply
Robert,
Thanks for reaching out. Unfortunately, we are not sure of the proper modifications for the “later” version of this valve. We recommend waiting to hear back from Heiden, as they are the most familiar with their products.
Thank you,
MXS Customer Service

 

[Its been a long time]

Hi, I recently bought one of these reed valve breathers from Heiden Tuning. There are no fitting instructions and I cannot get a reply to questions re fitting. There seem to be two versions, early and late. I see you recommend [SIZE=6]drilling out an oil drain hole [/SIZE]with pics of the early version. Does this apply to the later version please? On the later version the screws have tamper-proof markings and are very tight which implies it Is not intended to be opended up. Can you help please? Robert
3
Sam White on October 2, 2020 at 8:32 am Reply
Robert,
Thanks for reaching out. Unfortunately, we are not sure of the proper modifications for the “later” version of this valve. We recommend waiting to hear back from Heiden, as they are the most familiar with their products.
Thank you,
MXS Customer Service

Hmmm. I bought one of the reed valve breathers from Heiden Tuning a few months ago. No instructions with it. I just bolted it on and ran a hose off it. I get a nice gentle chuff, chuff, chuff from the end of the hose. And so far, not a drop of oil from it.

 

[Mikey]

Hi, I recently bought one of these reed valve breathers from Heiden Tuning. There are no fitting instructions and I cannot get a reply to questions re fitting. There seem to be two versions, early and late. I see you recommend drilling out an oil drain hole with pics of the early version. Does this apply to the later version please? On the later version the screws have tamper-proof markings and are very tight which implies it Is not intended to be opended up. Can you help please? Robert
3
Sam White on October 2, 2020 at 8:32 am Reply
Robert,
Thanks for reaching out. Unfortunately, we are not sure of the proper modifications for the “later” version of this valve. We recommend waiting to hear back from Heiden, as they are the most familiar with their products.
Thank you,
MXS Customer Service

The instruction were for the Mike's xs version of the valve
It just seems odd that if it's for an xs650 why you would need to modify it