650 SX PCV valve

hi highdesert,it needs to be fitted in the breather pipe between the crankcase and oiltank or the rear of the timing cover and oiltank,if your not sure which way round it goes do a simple blow test ,you can only blow through it one way,this is the side you fit towards the engine,i would secure it with hose clamps

The #44 hose is the path you want to insert the XS 650 PCV valve. Output side of the valve to the oil tank. I would find a suitable place to mount the valve first, it has a hole drilled in the bracket for a bolt mount. Then plumb the 1/2" breather hose to the input side. In most cases the 1/2" hose will need to be shortened. You'll probably need a new length of 3/8" hose from the output of the valve to reach the spigot on the oil tank, that's the #45 hose. Hose clamps are optional.

So I'm on Mikes sx web site looking under "engine" subcategory "Lubrication: Oil Pumps, Filters, Gaskets, Fittings" and I can't find a pcv valve. I've combed through the other sections too. Can someone point me to the subcategory where it's hid?

http://www.xs650direct.com/products-3.html

http://www.xs650direct.com/products-40.html
http://www.mikesxs.net/products-40.html#products
Reed type PVC Valve

Thanks, I just found it too under "fuel systems"

RennieK said:

So I'm on Mikes sx web site looking under "engine" subcategory "Lubrication: Oil Pumps, Filters, Gaskets, Fittings" and I can't find a pcv valve. I've combed through the other sections too. Can someone point me to the subcategory where it's hid?

http://www.xs650direct.com/products-3.html

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Yeah, it's actually on the "Fuel System" page under "Carb Holders, Air Filters, Fuel Filters, Breather Vent Parts". Try this link: http://www.mikesxs.net/products-40.html#products It's part number 15-0677, about half way down the page.

JimC said:

The #44 hose is the path you want to insert the XS 650 PCV valve. Output side of the valve to the oil tank. I would find a suitable place to mount the valve first, it has a hole drilled in the bracket for a bolt mount. Then plumb the 1/2" breather hose to the input side. In most cases the 1/2" hose will need to be shortened. You'll probably need a new length of 3/8" hose from the output of the valve to reach the spigot on the oil tank, that's the #45 hose. Hose clamps are optional.

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Just so I'm clear. . . Does the #44 hose normally connect to the #45 hose via the adapter (#46)? (the diagram is a bit confusing) So basically you replace the #45 adapter with the valve?

So basically you replace the #45 adapter with the valve?

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You could say that. Just keep in mind you may have to change length of hoses, unless you can mount the valve in the same area as the adapter is currently located. In other words, if the valve were to be located on the back of the air filter, as I did, you would have to shorten hose #44 and replace hose #45 with a longer hose. The adapter #46 would no longer be used.

Some much cheaper plastic PCV valves were being handed out at the INOA rally in Lumby, BC. Canada a few years back. You had to lose the adapter (#46 in the exploded view above) and use a larger line to the oil tank.

Mine's been on since then. The primary wasn't leaking before, and it isn't now, which means, well, nothing. However, going to the local parts store with the #46 adapter and finding a 3 or 4 dollar valve with the same hose size might save you a few bucks.

Vertigo said:

Some much cheaper plastic PCV valves were being handed out at the INOA rally in Lumby, BC. Canada a few years back. You had to lose the adapter (#46 in the exploded view above) and use a larger line to the oil tank.

Mine's been on since then. The primary wasn't leaking before, and it isn't now, which means, well, nothing. However, going to the local parts store with the #46 adapter and finding a 3 or 4 dollar valve with the same hose size might save you a few bucks.

Click to expand...

Does that plastic valve have a metal reed ? If it has a rubber diaphragm type flapper I'd be suspect of it's effectiveness.

Hey, welcome to the forum Vertigo!

Maybe next year we'll get better pcv valves at Lumby...

Even if they were cheap plastic they could have been enough to convince the installers that they should invest in a good one.

Ok, thanks the replies to my questions on the valve.
Here is my next question: Looking at my 73 850, I see the large diameter hose coming off the back of the timing cover.
My understanding is that I need to locate the valve in that hose somewhere before it gets to the tank. Correct?
Ok, now I have also read on this forum that the close it is located to the timing cover, the better.
Well, then why not just cut the big hose in half maybe two inches or so from the timing cover and locate the valve right there.
Let it hang, it doesn't look like ti would hit anything hanging approx. above the two engine plates between the motor and gearbox.
Now, I just ordered it so I don't how big the valve is, maybe it is too big for some reason to fit it there?
Or is it no aetheticially pleasing to locate it out in the open right there, is that it?
So, why locate it back of the air filter if it is "better" in function to locate it right directly in front of the timing cover?

I think the weight of the valve and the vibrations of the Norton engine would cause the hose connections to fail. I'd be afraid to attach the valve to the timing case using the supplied bracket, as well. I'm certain the bracket would soon fail from vibration. I've been using the mount I pictured for some 5000 miles with no problems, although it is farther from the crankcase. I believe Jim Comstock's research showed the closer to the crankcase, the more efficient was the PCV valve.

I need to understand something here. PCV valve lets air out but not in. So hows the air get into the motor? Hows this work on a Commado?
On a car, the PCV vents into the inlet manifold and on one end of the rocker cover is a ventilation breather that draws clean air from the airfilter to circulate into the motor. I've got a 1/4' breather hose on top of the inlet rocker cover and I'm going to fit a Kel-Pro PCV valve this weekend. Do I need to keep the the breather hose or block it off?
Thanks,
Mick

ML said:

I need to understand something here. PCV valve lets air out but not in. So hows the air get into the motor?
Thanks,
Mick

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Blowby past the rings is probably the major culprit.

Agree blow by is probably the major component of bad air getting into the crankcase. On my 850 I run the timing cover breather hose up into a catch bottle alongside the battery. This then has a 2nd hose exiting into the oil tank at the filler neck. The oil tank outlet breather then goes to atmosphere. By that stage the air venting is pretty clean, but the blow by filth that gets dumped into the catch bottle from the timing cover breather is what I'm avoiding contaminating the oil in the tank. I'm going to fit the new PCV valve on to the timing breather as close to the engine outlet as I can and then route the hose back up to the catch bottle. I will experiment with the extra inlet rocker cover breather and see if it makes any difference. I'll run it open and blocked and see what happens.

Mick

Hello, I would have thought the air / oil vapour that comes out the breather shouldn't be much dirtier than the oil in the oil tank ?
Not having started my 850 yet, so I have no idea ?
I would have assumed a catch bottle went after the oil tank ? (if one was needed on a standard Commando)
Is a catch bottle needed if the system was plumbed, crankcase, pcv valve, oil tank, hose, then small air cleaner ?

I have a Mk3 with 1 Mikuni and a K&N type air filter.

Thanks
Graeme.

With my bike, I just got the cheapy motormite power brake check valve, and replaced part #46 with the valve - inlet is the same size as the hose coming off the timing cover, and the outlet is the same size as the hose going into the tank. Also, since the fittings are at 90 deg to each other, it fit nicely right where the original hose bent around the top of the tank.

OK, so it doesn't have a nice metal reed valve, but it works, isn't conspicuous, and cost about $5.

Dorman/Motormite Brake booster check valve #80190

Bill,

How many miles have you been using the Motormite valve? I tried a couple of them, but they weren't effective after a few hundred miles.
The Motormite is certainly simpler and less expensive to install than the others available. I'd of stuck with it if it had worked for me.

I put mine on last November, and have put over 5000 miles on it since then. I haven't had any issues with it.

In fact, I haven't had any repeated issues with the bike - every time something happens to it, it's something new.



I take that back, I did have one repeated issue:
I put the 850 pipes on the bike when I first put it together. After my first real long ride (about 180 miles) I found the left pipe cracked at the crossover 'Y'. I went to Wes' shop and bought a used left pipe for $40. It lasted 100 miles before it cracked. Went back to Wes and got two 750 pipes and lock rings. That was the end of my exhaust issues.

After the initial shakedown and debugging (July-October of last year) I've replaced:
Exhaust pipes, 850 to 750, in November
Crank seal, in November
Motormite valve, in November
Kickstart lever, Racing Spares to Norton MkIII, in January
Head Steady, box section type to Dave Taylor, in January
Fuel lines, from 'H' style to double-banjo style, in January
Speedometer drive, in March (failed at 530 miles of a 600 mile day)
Speedometer cable, in July (bungee accident)
Primary chain, in August
Kick stand, in August (original didn't have toe tang or bumper on it)

Of course, a couple of oil changes and a rear tire, too, but that's just normal use stuff.