Crankcase Breathers.

[koko64]

Crankcase breathers seem to come in a few types. I noticed that the old alloy and newer plastic OEM parts appear very leak prone and the plastic version subject to cracking from what people say. My old M900 has the earlier alloy version and it began to leak. I changed the gasket and applied sealant and it's been fine. The reed valve appeared in good working order too.

I am leery of retro fitting the plastic oem type to older Monsters as I would like to torque them up a bit. So aftermarket types appear the go and come in colours if you like.

I'm interested in the different reed valve designs and how sturdy and effective they are.
The different aftermarket breathers come with different reed valve material ranging from special plastics to carbon to alloy. EDIT: The reed valves I thought were alloy are most likely stainless. The reed valves in my alloy stocker had a pivot hinge, but some appear to be designed to flex via thin material. I like the hinged/pivot type on first impression.

Anyone have any thoughts or experience with this?
Cheers thanks.

[Heath]

When my plastic one started leaking on my S2R800 i replaced it with a breather from Nichols. It has the flex type reed valve. I assume it is still holding up fine but I haven't had to open it for a long time. I plan on getting one for the S4R if it starts leaking or I get some extra dough.

http://nicholssportbikes.com/products/NBREATHER.html

You can get it from CA Cycleworks
http://ca-cycleworks.com/nmibreather

[koko64]

Thanks Heath (I always think of our late Heath Ledger when I see your posts, don't really know why).
I couldn't find it on the CCW site for the life of me, thanks for the link. That one uses the special thermo plastic reed that's supposed to be very durable. The Oberon uses carbon reeds, the SSR one seems to use alloy from their site. I am leery of something flexing a gazzilion times, so I like my old stocker. I'm just not sure which type to recommend to people when they need or want to replace that part.

Our sponsors are reliable and sell good stuff, but I'm having trouble getting my head around the flex type reed valve. Mind you, a pivot/hinge can wear and have issues also.

Edit: The part description mentions a "roll pin". Maybe this has a pivot/hinge function?

[Speeddog]

The fiberglass reed material was very common for 2-stroke reed valves.
Quite durable in that application.
Although, they has a nice curved steel 'stopper' behind them, which helps a lot.

[koko64]

G'day speeddog.

I was wondering how they compared in application. The reed actually pivots with no resistance on my old stocker.

[Speeddog]

Oddly enough, I've never opened an old-style stocker.

The two-stroke reed valves are like so:



Carb flange attaches to the bottom side as shown.

That one is Yamaha style, a rubber coated aluminum body, stainless steel reeds, and steel stoppers.
With the rubber coating, the stainless would live, and the stainless reed is quite flexible and doesn't take a 'set'.
Occasionally they break off, and get sucked into the works, and then everything looks quite second-hand.

Fiberglass ones are a little less flexible, and take a bit of a 'set', so don't seal quite as well.
But they're totally digestible, a broken one gets mauled and what's left blows out the pipe.

[koko64]

Any thoughts on an alloy reed valve?

[Speeddog]

An aluminum reed that flexes?

Or one that is on a hinge?

[koko64]

An aluminum reed that flexes?

Or one that is on a hinge?

The SSR breather reed valve looks bolted down. The part description is "alloy filter" on the slingshot site.

[Speeddog]

The SSR breather reed valve looks bolted down. The part description is "alloy filter" on the slingshot site.

http://www.slingshotracing.net/catalog/ducati-cnc-billet-oil-breather-p-150.html

It looks like a stainless reed.

If it's an aluminum reed, it'll break sooner or later.

[koko64]

Thanks.
The alloy filter must be a mesh I guess.

[brad black]

if the late plastic ones start leaking i remove them and goop the thread and o-ring and refit.  generally i don't like gooping o-rings, but it seems to be about the best.  plus the goop will help keep it tight.  if you can't get a spanner on it (you generally can't when it's assembled) i put a piece of thick rubber around the snout and use multigrip s(channellocks) to grip and tighten gently.  plus the hose when clamped will help hold it in place.

i don't see the need to go aftermarket personally, but that's just me.

[koko64]

Ever seen any cracked ones, maybe from over tightening?

I gooped my oem alloy one with a new washer. It's fine.

[brad black]

no, don't think i've ever seen any cracked ones.  i'd go a plastic one every time.

[Rudemouthsky]

I got this last year, it looks almost identical to the Nichols but it's Ducati brand and part #,  966019AAA.

http://www.powersportsnetwork.com/enthusiasts/catalog_item_detail.asp?catalog=3607&levelcode=25394&product=429244&cattype=&ProductCategoryCode=

I run a little knock off K&N $4 filter directly attached to it, never had a leak or any misting even when wheely-ing. it was $100 I think on ebay.