Could be true in some cases. But in my case, in March of last year I bought and installed an HD Ventilator air cleaner for my Street Glide and eliminated the bypass setup I had. In August I serviced the air filter, and after 8k miles there was zero oil in my throttle body from the head vent tubes. Trask made a believer out of me.

 

Skip the Dipstick, and get a Transmission Case Vent. I got the TRASK CheckM8.
Get a temperature Dipstick instead. That's the combo I got.
It's nice to look down and check my oiltemp. It was 54$ when I bought it.
I installed the CheckM8, then removed the Vent Tubes in my air cleaner.
Solved the re-ingestion problem, and now I got a nice temp gage.

 

Fan if A1’s dip stick vent. Inexpensive very effective and simple. Also make your own vent to atmosphere or catch can instead of leaving no oxygen oily air back into your into your combustion chamber through the Throttle Body as Harley is currently doing to pacify epa.

 

Just curious if you have modified your air cleaner to vent your blow-by to the atmosphere. You won't notice any blow-by if it's being directed back into your engine (stock configuration) to be burned off. I was getting a small amount of blow-by after modifying my air cleaner until I installed the Trask vented trans cover. You can go online and see examples of the crazy carbon build-up of M8 engines left in the stock air cleaner configuration.

 

According to their description on the website, the dip stick vents are only for Touring or Dyna models.

 

Speaking of in tanget, I'm going to modify my CheckM8 with a much shorter hose, and a hose clamp. I want to try a different position for the filter.

 

Thanks. The HD Ventilator A/C solved your blow-by problem? Or the Trask? The Ventilator is roughly half the cost of the Trask A/c.

 

Neither will solve an excessive blowby problem, but here's a rundown of what I have done to eliminate the oily/messy air cleaner.

I did a bypass on the head breathers with my SE wedge style air cleaner, no more mess. Then Trask came out with the Check M8, so I got one installed in Sturgis at the 2021 Rally, and had both the Trask and the bypass. ( https://www.hdforums.com/forum/milwa...rspective.html )

In March of 2022 I decided I wanted the Ventilator AC, and installed it as designed without a bypass setup. In August, 8k miles later I serviced the air cleaner element and there was no oily residue from the breathers to be found. So, for me, the Check M8 is doing what it was designed to do and has stopped the oily mess in my air filter. I'm sure the vented dipsticks will do the same, just in a different way.

 

Trask Vented Transmission cover. The perfect solution!

 

To followup on OP's question, if you have a slight oil residue on the throttle plate with stock setup, but have a late model M8 with current non-sumping oil pump and keep oil level correct (midpoint between low and full), do you think an open breather would still be worth doing to keep throttle body, intake valve, and pistons clean? Or woudln't it make much difference?

If yes, the Trask looks great, but I just installed a Stage II S&S Stealth air cleaner that uses vented bolts into the assembly. How to block those off? Or just leave it and hope Trask does enough of the breathing?