Hotop Designs Air Ramp for S&S breather gears ... snake oil or snake oil?

OK, since this is the 'technical forum' I am just asking as I cannot see any feedback/answers elsewhere.

Maker claims an "80% increase in CFM" over standard (much of which must come because you have to remove the metal screen). But is it really such a bottleneck?

I also read in Denish or Rook the idea of drilling out the holes in the screen to make them wider allowing more flow, Ditto, widening the aperture of the casting according to correct timing (S&S instructions), and enlarging the smaller window in the gear.

Now, fine ... yes, I know ... you know someone who's done 300,000 miles on a plastic breather and makes 130 hp ... so why bother? Fair enough. Why bother?

But, on the other hand, why not? Do any of these tweaks improve matters?

I'm not thinking of spending any money on one, I can see the advantages of having a screen to catch crap in a worse case scenario' but I can see the logic behind it and how it might be a pleasurable way to spend a winter's evening knocking one up.

 

the idea seems to be in what one would think could do the job

does it work maybe maybe not - a slight amount of time is added to the breather function using a screen, and in production one can imagine if it did nothing harley would not have done it

a real time advancement came along with the reed breather / its self adjusting to more loss - to more volume - and its specific timing becomes a non issue as well as the window size -

now tell me WHY it does work at all in only one over head valve Big Twin harley engine / the knuckel < but the valve fits 1936 to 1954 into the 1948 and on panhead era same stock breather valve

this will set you straight with what it does and how it works and why one should use it

The S&S reed breather

 

I know of the reed valve but have never used one, and I know you like them. Do they have a built in screen to filter any junk that might enter them? If not, then it suggests the Hotop is safe; though recently, we had a member find rubber strips in his and I have read of others who caught metal when some other part of the engine grenaded.

I don't know if I can agree with your statement, "one can imagine if it did nothing harley would not have done it" as it often seems H-D just do something or use something because they always have. The plastic one does not have a screen, just slots.

The riddle I cannot work out.

I can see from air flow/fluid dynamics point of view that the scoop has got to be good and it appeals to me for its obsessive attention to detail. I just hope it's drilled out from inside to reduce weight as much as possible ... ;-).

 

As an engineer, I remain suspicious of the reed valve for the simple reason that it relies on flexion of a "reed" to operate. As such, what happens when the reeds "break"? All materials have a fatigue life, and as such, it's not a matter of "if", but "when" your motor will ingest a reed.

 

i have used them from the time they came out maybe late 80s to early 90s, my guess i bought couple a hundred of them in the 90s alone - some bikes have plus 100 thousand miles on them - to date have not seen that come up maybe its as often as a 2 stoke bike eats one in its carb dont know