I've got a very nice brand-new custom breather "venturi sucker tube"
that I'm not using! One of a kind!
Heh-heh!

Yes, the check-valve like a Krank-vent or a duckbill are just fine.
I went off on a wild escapade, on this very subject, and in the end
the simple stuff is indeed the best.

Ace




--- In royalenfield@yahoogroups.com, Damon Fever <twotyred@...> wrote:
>
> fiferwd@... wrote:
>
> > I remember seeing something on the forum about installing a power
brake
> > check valve in series with the breather hose to maintain negative
pressure in the
> > crank case. Anyone tried this?
>
> Oh dear, now you've done it - this is the next best thing to "what kind
> of oil do you recommend?" I am the brake booster valve proponent. You
> can search the message archives for a part number and source; there are
> many suitable types. If you can't find em, I have them on my home
> computer and can get them for you. I've used this type of valve on big
> singles and twins for years to good effect.
>
> Another valve I like (but more spendy) is the Krank-Vent (Google it),
> and I presently have one of these on my Bullet. The main benefit of
> these valves is reduction of crankcase pressure below atmospheric
> pressure; this tends to keep oil inside the engine. There are also some
> windage benefits at high rpms but that is not our concern with
Bullets, eh.
>
> I have not performed pressure tests myself but have seen results of
> tests by people I respect, and they indicate about a 2psi reduction
> below atmospheric. My engines do not weep any oil, which is more than I
> can say for Bullet's gearbox ;-/ There is no downside other than the
> cost of the valve, which is minor if you choose one of the cheaper
brake
> booster valves. Make sure it's installed blowing OUT!
>
> Cheers
> Rick F
>