Reed valve engine breather.

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Reed valve engine breather.
I made this little gizmo yesterday, finished it off this morning with the bead blaster. I was going to polish it, but damn this gizmo looks good with a bead blasted finish.
Petal was taken from a pit bike read valve and cut in half, two holes drilled and screwed to the base plate. Base plate was tapped M3 10mm deep to take the petal. Not fun tapping this small, but, this time around the tap survived.
Main body was carved out with an endmill to give the petal room to move and air to flow. Base plate has a channel on the engine side for any oil to run down back into the rockers. Topside was channelled either side to get the Allen heads level with the top surface. Stainless Allen's were turned to make them shiny, I do like shiny baubles.
Outlet spigot is 16mm with a 10mm hole. If it's not big enough I can take it out to 12mm later on.
Air from the engine enters the main body from the reed valve is channelled upward, does a U turn and travels downward to the outlet spigot, losing a little oil on the way. Any oil trapped before the reed valve is channelled back to the rockers.
I'll have to design and build a catch can now, thinking of mounting it behind the downtube between the carbs. But, it's getting a little busy in that area.
Manual machining only, would love a CNC, but not in my budget, would've made things a lot easier

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More pics.

[docmel]

More pics.

Not sure what bike it goes on, or what the item is actually for. But I do appreciate the craftmanship. If its an item that is useful for certian bike owners, advertise that shit! could be a seller

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Same as a PCV (positive crankcase ventilation valve) you find in all modern cars and motor cycles, maintains negative crankcase pressure by allowing blow by gasses to escape the crankcase and preventing air from entering. The blowby gasses are generally fed to the intake where they are burnt in the combustion process. basically an anti pollution measure, also stops the oil from gunking up from unburnt particles and gasses.
They are available commercially, I just prefer to make my own stuff.

[docmel]

Got it Great work. Just like the make shift crankcase breather on BTs that most of just have: a long piece of hose! Can you post more pics?

What make/model MC is that one on?

[farmall]

Road draft tubes and vent hoses aren't makeshift and their use dates to the early years of the automobile and motorbike. Less well vented engines like Norton Commando often get custom check valves like OP made. They work well. HD already have either rotary or flapper check valves making more redundant except maybe for large, custom race engines.

OPs engine is an XS650 where that style valve tidies it up nicely.

Aftermarket version, valve origin unknown to me (I've not touched an XS in many years):

https://www.mikesxs.net/yamaha-xs650-reed-type-engine-breather-valve-pcv.html?fits-motorcycle=Yamaha/XS650/all-models/1971

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The build.

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Now the bike is almost finished, just needs the seat covered and tyres, so I put on my glasses and cast a critical eye over it. Story of my life – never, ever happy, and what do you know, I found a few things I’m not happy with, so, I can start making parts for it again, whoo hoo!. First up was a new spin on filter/cooler. The current one totally underwhelms me: hoses look untidy, the spin on filter mount looks too blocky, so, that went in the bin. One of the screws holding the mount to the engine bracket was a bit hard to get at, so, the right engine mount went in the bin. The cooler bracket is just plain terrible, didn’t like the mounting method nor the look of it, plus the rubbers I felt were too small, so that also went in the bin, along with the left engine mount.

So, back to work: first up was a new spin on filter mount, I put a little shape into this one: rounded the edges, turned a cone on top and pressed the inlet spigot into the side of the mount, so the outlet hose from the front of right engine cover is only around 4’long and attaches to the inlet spigot of the spin on mount on the side, just in front of the engine mount. Much more neaterer!

Next came some new engine brackets. The spin on mount is still mounted in the same manner, just set further back, so, the engine bracket protrudes further back, almost touching the engine case. This allows the rear allen head that was hiding behind the down tube to be moved further back, so now it is to thebrearnof the downtube and thus easy to get at.

Next came the cooler mount, the original I made was a piece of 3mm ally, bent at a right angle and bolted to the front of the engine brackets via four allen heads. Didn’t like that, so I extended a goose neck on the front of the engine brackets out about 30mm and drilled and tapped holes in top for mounting the cooler bracket.

The cooler bracket, is now just a flat section of 3mm ally, with larger holes drilled to take bigger, thicker gromets and is secured to the top of the engine mount goose neck protrusions via four stainless button heads. To mount the cooler to the bracket I spun up four threaded T nuts that are inserted into the gromets from underneath and the four long bolts secure the cooler to the top of the bracket. The T nuts prevent the gromets from being squished too much.

Now I just have the one long hose over the engine bracket connecting the cooler outlet spigot to the right engine cover. A hose connects the spin on mount spigot on top to the inlet on the cooler. I’ll retain the black rubber hoses as I don’t like the look of braided hose: to silvery and hard to keep clean down there with all the road debris and the black hose is a little less intrusive.

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More pics.

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I managed to drop the seat, so had to strip and straighten it, the calipers crinkled in a couple of spots, must had dropped some brake fluid on them, so I also stripped and repainted them. 2k paint, so I'll wait a couple of weeks before taking it in to get covered.

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I was going to plumb the read valve engine breather into the pancake filters, but didn't like the idea of breathing sump gasses into the inlet, so, I made this catch can.

Not quite finished yet, I rushed it toward the end to see what it'd look like, happy with the result, So I'll probably build a neater one, with a few changes of course.

Matches the pancake filters, but almost unnoticeable

[Revelator]

nice work on that oil cooler. just the right size, not too bulky and best
thing is that you made it yourself with style.
that yammy motor looks terrific!

[Revelator]

A buddy of mine ran the case vent on his shovelhead directly to the
oil tank ( 2 vents at the tank, 1 lower case vent and the other is the upper
case vent near the oil pump.) along with that he mounted a PCV valve on the
oil tank. He says it has worked flawlessly for years.

Myself, I just run an 18" long piece of rubber hose with a small crank breather near
the tail of the bike. i don't remember what brand the vent is but it works well.
let everyone know how that reed valve works out. it resembles the reed valves on
2 stroke mx'ers (intakes). example: boysen reeds

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Blowby gasses from the crankcase have all sorts of contaminants in the carbon, unburnt fuel and so,on. Not a good idea to be mixing it with the oil in your oil tank!

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So, I finally settled on a catch can design and built it. The first one was simply too big, creating mounting problems, so that was binned. The final one is made of 42mm tube with four baffles. Instead of welding the baffles inside of the tube, I fixed them together with a 4mm screwed and peened the end so it wouldn’t come apart, the baffle cartridge was then pressed into place resting on top of the intake tube so it won’t float around. The intake tube stretches across the diameter of the 42mm tube and has three exit holes underneath. For the blowby gas to escape it has to exit via the four baffles and finally through some stainless mesh before exiting through the air filter on top, set between the two carb filters.

I’ve gone with a remote empty point via a tap connected to the catch can by a rubber hose. The filtering medium inside the can is replaceable via the top plate secured on top by four 4mm stainless allens. The can is mounted to an aluminium bracket by two rubber gromets and two threaded T nuts to stop the gromet from being squished too far, then fixed to the right, rear engine bracket.

Mounting the can proved a little troublesome: behind the motor over top of the swing arm pivot is the only place I could find to mount it. To make it less noticeable I painted it black and welded an outlet on the side so I could mount the final filter between the two carb filters. It is only a small catch can with around 220ml capacity, that’s in total of course, realistically only around 100mm under the baffles. If it proves too small, I can fit a larger container under the swingarm connected to the catch can outlet by a rubber hose.

It’s very busy in this are area now, two carbs, three filters, catch can, fuel distributor block, making it a little difficult to remove the air filter caps.