Reed type PCV Valve

chasesa · Dec 19, 2009

I wish to install a "Reed Type" PCV valve on my Norton to relieve crankcase pressure. However, when I go to parts shops they want to know what car & model PCV valve I am looking for. Without that, they are no help!

Can anyone suggest a car model & year that I can use so the parts guys know what I am looking for?
Thanks!
Stephen

maylar · Dec 19, 2009

There are no auto parts store solutions, other than the Motormite power steering check valve which many report are short lived.

Search the forum for "breather", there have been numerous posts on the subject. The most popular device is one sold by MikesXS dot com.

chasesa · Dec 19, 2009

Thanks Dave.
On this basis, & avoiding running all over town, the path of least resistance would be simply to order from Mike's.
Stephen

debby · Dec 19, 2009

maylar said:
There are no auto parts store solutions, other than the Motormite power steering check valve which many report are short lived.

Many people or one person?

I haven't had any trouble with the motormite pcv on my 850 although I must admit it's only been on there for a few hundred miles. I bought it at one of the local car parts places, off the rack. It's actually a brake booster check valve, not a pcv, but it was in the same section. A helpful clerk actually found it for me, which I must say is unusual these days.

Debby

ILLF8ED · Dec 19, 2009

Hi Debbie,

I have to admit I was reluctant to try the Yamaha reed valve. After replacing the motormite with this, my valve cover leaks stopped. I suspect the motormite works, but the Yamaha part works even better. Another thing I noticed is when draining the oil from the sump it comes out very slowly now as no air is getting in to allow the oil to flow easily...suppose that's a good thing.

Going to the root cause - there must be a reason due to wear the makes the reed valve necessary. A new engine never needed it. So, are we treating the symptom and not the cause.

Fullauto · Dec 19, 2009

illf8ed said:
A new engine never needed it

If Norton had fitted a one way valve in the breather in 1968 we would have had leak free Nortons with more horsepower right from the start.

Triton Thrasher · Dec 19, 2009

illf8ed said:
A new engine never needed it.

They were inclined to leak a bit if thrashed.

maylar · Dec 19, 2009

debby said:
maylar said:

There are no auto parts store solutions, other than the Motormite power steering check valve which many report are short lived.

Click to expand...

Many people or one person?

I haven't had any trouble with the motormite pcv on my 850 although I must admit it's only been on there for a few hundred miles. I bought it at one of the local car parts places, off the rack. It's actually a brake booster check valve, not a pcv, but it was in the same section. A helpful clerk actually found it for me, which I must say is unusual these days.

Debby

Reports of life expectancy vary from 10 to 3000 miles. Bottom line is that they're not designed to 'switch' at the frequency we need for cranckcase pressure control. Mine lasted 200 miles. I hope your experience is better.

maylar · Dec 19, 2009

illf8ed said:
Going to the root cause - there must be a reason due to wear the makes the reed valve necessary. A new engine never needed it. So, are we treating the symptom and not the cause.

I've owned my 850 since new, and I can tell you that the oil seal at the tach drive (a simple o-ring) spewed oil all over my right foot while the bike was still in warrantee. Valve covers leaked from the day I rode it off the dealer's lot and the timing cover gasket leaked within 15,000 miles. A new engine definitely needed it.

lcrken · Dec 19, 2009

maylar said:
There are no auto parts store solutions, other than the Motormite power steering check valve which many report are short lived.

Search the forum for "breather", there have been numerous posts on the subject. The most popular device is one sold by MikesXS dot com.

I know MikesXS used to sell the Yamaha reed valve breather, but I can't find it on his web site. Anyone know where it's hidden. I remember seeing it in the past, but can't find it now. Thanks.

Ken

JimC · Dec 19, 2009

http://www.mikesxs.net/products-40.html#products

You need to scroll down on the page.

Gary · Dec 20, 2009

Do we have a write up, or posted pics of it installed for a beginner like me?

JimC · Dec 20, 2009

GRM 450 · Dec 20, 2009

Hello, my newly rebuilt engine leaks. Fix one leak and then there's 3 new leaks.

I bought a Ducati reed valve pcv and made an adaptor for it to be an in line pcv.
They are fitted to 2 valve motors from 750 up. Probably 4 valves as well, but I don't know for sure.

It rained all weekend so I didn't get to try it out .
(pictures to follow)

graeme

This is what they look like, $20 approx on ebay.

Inside, you can see the 2 reeds.

you just need some alloy round and access to a lathe and some time.

The pieces

JimC · Dec 20, 2009

The PCV valve should be called the leak eliminator. I chased my tail around replacing the crankshaft seal many times. Finally installed the PCV valve. Viola! No more leaks.

chasesa · Dec 20, 2009

Can anyone advise where to install the PCV valve on a '68 Commando?

Mine has the breather line attached to the cylindrical "dome" on top of the oil tank. Is that the correct line?

My Commando also has a crankcase vent hose that connects to the crankcase just below the left cylinder. (I can't remember where it goes as the bike is safely away for the winter). How about that line?
Stephen

mcns · Dec 20, 2009

Chasesa, you have the same set-up as I did (71 motor) which means you already have a timed breather built in to the end of the camshaft on the drive side.
The problem some with that set-up is air can only escape through 1/4 hole, when I bought my 71 it was a rolling basket, so when I split the cases I drilled two holes in the timing side, then exiting where the 850 does and completely blocking off your exiting breather.

There is a thread on the old britts page that will tell you what size holes(I think 3/8) and where to drill, the problem is your cases will have to be split.

good luck

Gary · Dec 20, 2009

Once again... does anyone know where I could go for a tech write up/installation proceedures, preferrably with pics, so that I can print off and eventually do this mod? It's rather frustrating to read all the different threads about really great mods... but no clue HOW, nor even WHAT...

(there's nothing when I search the old files for it...???)

JimC · Dec 20, 2009

Gary,

The installation is rather straightforward. The Mike's XS 650 valve or any PCV valve, needs to be placed inline between the crankcase breather outlet and the oil tank or collector. The larger diameter spigot is the inlet. Cut the breather hose at a suitable location and connect to the 1/2" hose going to the crankcase. The output spigot connects to the oil tank (usually) via a 3/8" hose. The Mike's XS 650 valve needs to be solidly mounted. The mounting point is up to the installer. The back of the air filter is a natural for following the breather hose routing.

CNW has a more efficient valve , according to Jim Comstock's testing.

bpatton · Dec 21, 2009

The problem with the Motormite is that it's a checkvalve for the power brake booster. It's used to hold a vacuum behind the diaphragm for when you need to tromp on the brakes in a hurry. It isn't designed to handle oil or heat, or to do any rapid cycling. It goes between the intake manifold and the brake booster. Clean, dry, and relatively cool. It's like asking an anti-sump valve to cycle thousands of times a minute.
There are valves at the autoparts store that work ok, like an AV13. They need some fettleing to setup with a brass fitting to mount the output barb. You can mount it closer to the engine and they are cheap. CNW's valve is probably the best one going though. This is from Michael Moore's site on PVC's. it has some good thoughts on the subject.
http://www.eurospares.com/sucker.htm
I put this together years ago and have about 20,000 miles on it. Don't laugh, it works fine. it doesn't seem to be pulling out oil. It doesn't effect the carburation because blowby isn't exactly oxygen rich. MkIII's ran a tube from the intake to the oiltank vent which would probably be better, especially with a PCV in the crankcase breather line.

Reed type PCV Valve

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