![Capture%2Bd%E2%80%99e%CC%81cran%2B2015-03-08%2Ba%CC%80%2B16.43.43.png](/community/proxy.php?image=https%3A%2F%2Flh3.googleusercontent.com%2F-aE1ZkLzTEc8%2FVPy07kYdULI%2FAAAAAAAADB4%2FZXyfKcztUzc%2Fw1028-h578-no%2FCapture%252Bd%25E2%2580%2599e%25CC%2581cran%252B2015-03-08%252Ba%25CC%2580%252B16.43.43.png&hash=b3292685fac2672f794d7a33a70e2cfa)
Certified CarbonCubs do also have oil breather tube residue buildup problems. http://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CB8QFjAA&url=http%3A%2F%2Fwww.cubcrafters.com%2Fpdfs%2Fservice-instructions%2Fsi0023.pdf&ei=nbb8VL_mOZCYyASRi4LACQ&usg=AFQjCNG-auHGEJ1P8RWMG7u73h3aFm7ecg&sig2=ToF55JmeeA4ILEPM_d4uOA
And they don't look to have any valve on the breather tube.
Why put a valve if they don't??
![Capture%2Bd%E2%80%99e%CC%81cran%2B2015-03-08%2Ba%CC%80%2B16.44.09.png](/community/proxy.php?image=https%3A%2F%2Flh4.googleusercontent.com%2F-WXhQSWqXEnk%2FVPy06glASnI%2FAAAAAAAADBw%2FjDV4L4txqzA%2Fw1028-h578-no%2FCapture%252Bd%25E2%2580%2599e%25CC%2581cran%252B2015-03-08%252Ba%25CC%2580%252B16.44.09.png&hash=6c94bd7e855d193e2ed9b7732b889a88)
The way the breather tube is oriented in the exhaust pipe should only create vacuum.
On a single exhaust pipe, why not put a 90 degree bend in to the flow?