As one of my country friends used to say “ It’s as useful as **** on a bull”.

 

I ran the bike without the vent for about 100 miles and with the vent for about the same distance over the same route. The motor seemed to spin up faster after the mod. Like I mentioned, this a just a seat of pants observation. To each his own, regarding how to upgrade their motor. With a previous motor that suffered a failure, I am looking for any options that could decrease future chances of engine failure.

The idea of lowering case overall pressure during piston cycling makes sense to me. My limited understanding is venting reduces energy loss as the motor fights the differential pressure between cylinder top (during post spark down stroke) firing and cylinder bottom (case area). The reduced energy loss allows for more stored energy in the moving parts.
I am no engineer and would step aside for any smart person to chime in.

 

*when used with Amsoil

 

I agree!..The seat of the pants lift I got made me go, "holy ****!". I definitely felt it! The proof is in the puddin. Releasing (reducing) that pressure in the crankcase did something @ the lower RPMs. If you got a big bore kit, it just might give you that edge vs. your buds.

 

Some here may recognize this bike, not saying this makes it right but they too must have some reason for it.

 

I was thinking about going the route, but $300 for it was a hard pill to swallow. I ended up venting the oil tank using a $5 fitting since I have a liquid cooled head. All in I did it for $20 and I don't have to deal with the vent line on the dipstick every time I check oil.

 

. How is this done? 2017 Ultra Limited

 

The subject is a vent for an oil tank.

It seems from the posts here that some are confusing the oil tank with the crankcase.

An external crankcase breather simply re routes the oil that is spewed from the breather, it does not change the breather pressure in the system.

My opinion is that this kind of stuff is designed to generate revenue, not cure problems.

Like a lot of fishing lures, they are designed to catch fisherman, not fish.

 

[QUOTE=Dan89FLSTC;19672833]HD oil tanks are vented to the crankcase, not an open vent.[/QUOTE..

Absolutely.


and for INFO 101 for others


Even the external ones like the oil bag on a Softail, old cruiser, and Sportys have three lines on them. The third is the vent back to the main engine block. Vent gas goes one way up thru pushrod covers. Then out one way out poppet valves into the airbox. A little tramp oil falls out and runs down. Hardly any is drawn into the engine since only atmospheric pressure is driving air into a vacuum. Unlike the exhaust which is pushed out by piston... Primary share the transmission vent thru a hollow inner input shaft that the clutch rod push tube runs thru. That input shaft runs in a hollow output shaft to the drive sprocket cog pulley (cog belt drive )

 

COVERSOn the water cooled models, there is a blank/plug (part #35) installed where the oil cooled engines have the oil return line. Remove that, drill and tap for a hose fitting and your good to go!