Here is more on the Oceanside, California based Feuling Parts' new M-8 vented billet dipsticks that we featured in AMD a few months ago.
The design vents/breathes excessive crankcase pressure from the oil tank through a PVC style breather system consisting of a replaceable filter element and umbrella flapper valve. They screw into the factory oil fill spout as a stock replacement part and remove the unwanted build-up of blow-by found in all internal combustion engines with excessive leak-down through the rings/cylinders - a common issue, especially with large displacement and big bore engines.
Larger cubic inch, worn or loose ring clearance and engines pushed to their limits generally have increased blow-by. Blow-by is pressure that is forced past the rings and cylinders, pushed into the crankcase and then forced back into the oil tank. Feuling dipsticks help remove this unwanted pressure through a (CVS) Crankcase Ventilation System. Test results show a decrease in engine oil sump levels, more freely/smoother revving engine, increased MPG and decreased blow-by.
Feuling offers two options. First, a 1/8 NPT breather vent fitting with internal porous filter element. This option gives a clean look, however, it may produce an oil misting/residue out of the element on engines with excessive leak-down/blow-by.
The second option is a quick disconnect coupler fitting with rubber hose and filter element. This option will run any excessive oil misting/residue through the line and into the filter element. However, this option does require disconnecting the quick disconnect fitting in order to check the oil. "We recommend routing the line up the frame rail, up under the seat/abs area, then back down along the right side frame rail, and the filter element can fit cleanly between the engine/trans matting area on the inside of the lower right frame rail."
Feuling highly recommends staying off the rev limiter and running conventional oil in the M-8 engines to help maintain ring seal and minimize blow-by.
There are two ways to read the oil level with this dipstick, with the bike on the jiffy stand (FHS - Full Hot Stand) or the bike upright and level (FHU - Full Hot Upright). If reading the dipstick with the bike on the jiffy stand, take the reading from the dimples labeled FHS (Full Hot Stand). When reading the dipstick with the bike upright and level, take the reading from the dimples labeled FHU.
It is important to get the correct hot oil level in the bike and Feuling recommends running the oil level 95%-99% full when hot. The oil pick-up port is on the right side of the engine. Letting the bike idle or warm up on the kickstand will naturally fill the engine case and skew the oil level in the tank.
Feuling says that the proper procedure to achieve proper oil level is to check the cold oil level; then ride the bike until the operating temperature is reached; shut the bike off while still in the upright position (this ensures an accurate reading). Once the bike is on the kickstand, check the oil level and add or remove oil as needed.