Mounting Mike's XS reed breather

gortnipper · Jul 7, 2015

I bought a Mike’s XS650 breather reed valve which I have just put on my Mk2 (since I am not going to be doing any motor work in the near term so CNW/Comnoz’s case mounted breather wasn’t really an option for me now).

I originally put in in using the existing lines, but I was not happy with the reducers I had to kludge up to use the existing herringbone lines (the XS uses 3/8” hose, similar to the connector at the oil tank) nor with the extreme bend it incurred. So, I bought a length of 3/8” line, moved the reducer closer to the timing case, and gave more free play with the line.

But, I am still not happy with my “temporary” mount (temporary, as I am going to do some more major take downs in the future, and will figure out a more permanent placement for the unit). And, I notice that in zip-tying it on one day and the fettling needed to hook up the original hoses, then removing it the next day to reinstall with the new hoses – the zip ties have taken off some of the frame paint on the spine. And this is not even having been ridden yet, so I can only imagine this will get worse!

So, how have others mounted their Mike’s XS breather? Any elegant simple solutions out there?

CanukNortonNut · Jul 7, 2015

gortnipper,
I found that I had a lot of milky condensation in the oil tank when I mounted it that far back from the engine. Water in the bottom of the oil tank. Closer is better.
FYI.
Cheers,
Thomas
CNN

gortnipper · Jul 7, 2015

CanukNortonNut said:
gortnipper,
I found that I had a lot of milky condensation in the oil tank when I mounted it that far back from the engine. Water in the bottom of the oil tank. Closer is better.
FYI.
Cheers,
Thomas
CNN

Why is that, do you know?

I got some "mayonnaise" without it in my overflow bottle (red bottle in background) but no more than a couple teaspoons over a long while - and I am sure that his has more to do with some of the work on the bike I am doing that result in a 1k trip instead of a good long run.

Any pics of how you mounted it?

1up3down · Jul 7, 2015

yes,

I have mine mounted about one foot away from where the larger breather line exits the back of the timing cover right where it begins its upward move back and up towards the oil tank with the smaller diameter tube taking over for that job

o0norton0o · Jul 7, 2015

I put mine here:

and I carefully drilled my case from the timing side while I vaccumed the chips with a shop vac as I drilled

the inner case looked like this:

green arrow shows the valve body from inside mounted on the flat blanking plate I bought from old britts

red arrows point to an existing hole behind the cam sprocket and the 3/8ths hole I carefully drilled behind the intermediate gear for better air movement.

Yellow arrow points to a small 1/4" hole I drilled to allow oil to drain back to the crankcase so the timing chest wouldn't get flooded with oil, now that the crankcase was blowing air into the timing chest.

I have an early engine with the timed camshaft breather which I didn't disconnect, I just added a "T" to the oil tank return line and they both feed the oil tank .

I started the bike, ran it for a minute, then changed the oil to take any chips out of the crankcase. I went for a 10 minute ride, then changed the oil again... Then I changed it a week later.. You want to vaccum the chips, then "brake clean" the timing chest to take away as much of the drilling chips and dust as possible.

gortnipper · Jul 7, 2015

1up3down said:
yes,

I have mine mounted about one foot away from where the larger breather line exits the back of the timing cover right where it begins its upward move back and up towards the oil tank with the smaller diameter tube taking over for that job

A tad more than foot away would be about how much tube I have between the back of the timing cover and where it is now, I would guess. I bought a meter of hose and I would guess I have a bit more than a foot of it left.

o0norton0o - that is a bit more adventurous than I would be for this. If I was going to do that much work, I would do the Comnoz/CNW breather.

CanukNortonNut · Jul 7, 2015

gortnipper said:
CanukNortonNut said:

gortnipper,
I found that I had a lot of milky condensation in the oil tank when I mounted it that far back from the engine. Water in the bottom of the oil tank. Closer is better.
FYI.
Cheers,
Thomas
CNN

Click to expand...

Why is that, do you know?

I got some "mayonnaise" without it in my overflow bottle (red bottle in background) but no more than a couple teaspoons over a long while - and I am sure that his has more to do with some of the work on the bike I am doing that result in a 1k trip instead of a good long run.

Any pics of how you mounted it?

Condensation is the change of the physical state of matter from gas phase into liquid phase i.e. water droplets.
CNN

gortnipper · Jul 7, 2015

CanukNortonNut said:
gortnipper said:

CanukNortonNut said:

gortnipper,
I found that I had a lot of milky condensation in the oil tank when I mounted it that far back from the engine. Water in the bottom of the oil tank. Closer is better.
FYI.
Cheers,
Thomas
CNN

Click to expand...

Why is that, do you know?

I got some "mayonnaise" without it in my overflow bottle (red bottle in background) but no more than a couple teaspoons over a long while - and I am sure that his has more to do with some of the work on the bike I am doing that result in a 1k trip instead of a good long run.

Any pics of how you mounted it?

Click to expand...

Condensation.
CNN

Yes, I get that much! But why would you get MORE condensation in the oil tank with the breather further back?

CanukNortonNut · Jul 7, 2015

you just answered your question.
Edit: Look at Comnoz and Ludwig's design...I like them both.
Cheers,
Thomas
CNN

gortnipper · Jul 7, 2015

CanukNortonNut said:
you just answered your question.
Edit: Look at Comnoz and Ludwig's design...I like them both.
Cheers,
Thomas
CNN

OK - I understand why you would get more condensation from a remotely located breather than from a breather attached to the case:

comnoz said:
Your breather valve and catch bottle are both cold. That is why the water vapor exiting your engine condenses and collects in your bottle. Extra blowby from worn rings and bore will obviously compound the problem.

That is why I attach the breather valve to the engine and return the breather line to the oil tank. That way since the valve and tank are both "hot" the water does not condense out and is simply vented from the oil tank, still as vapor.

The only time I would see any "mayonnaise" around the oil tank cap on my bike was when I used to ride it to work and back repeatedly. That was a trip of only 7 miles and the tank never had a chance to get hot.
Then all it would take was a good 50 mile highway trip and any signs of water would be gone. Jim

But, I still dont understand why you would get more condensation from a line mounted breather that was potentially 6-8 inches closer on the line, unless the implication is that a breather on the line a foot away doesnt heat up enough to prevent the condensation, as it would 4-6 inches from the case?

texasSlick · Jul 8, 2015

Mounting the XS valve closer to the engine has another benefit other than condensation. Condensation is something, frankly, I never thought about. The other factor is something I worked on in my professional career.

A tube carrying a pulsating (back and forth) flow, requires more pressure to move a given volume as the frequency of pulsation increases. In other words, the crankcase pressure will be higher at high rpm's with a length of tube between the XS valve and the crankcase, than without. The one way valve mitigates the back and forth flow, but there remains some flow as the pressure in the tube cycles between expulsion of air and the response to vacuum of the rising pistons.

It is best to mount the valve as gortnipper did.

Slick

ashman · Jul 8, 2015

My breather hose from the timing side goes straight into a dump bottle so doen't go to the oil tank, my XS reed is mounted as close as it can be to the orginal hose that comes out the back of the timing cover, I don't get no condinsation at all and only get less than 50ml of oil in the bottle in a year of riding, having the reed valve so far up and nearer to the oil tank is not good, put it down low and near the timing case is the best place for it.

Ashley

gripper · Jul 8, 2015

I mounted mine like o0norton0o only pointing down and got a fair bit of oil in my catch bottle. turning it to point up with the pipe looping round to a catch bottle between the plates under the carbs reduced this a lot. I too drilled the 1/4" hole to the rear of the oil pump. I think it stops a chunk of oil just sitting in the timing chest getting hot and close to the breather.

o0norton0o · Jul 8, 2015

gortnipper said:
o0norton0o - that is a bit more adventurous than I would be for this. If I was going to do that much work, I would do the Comnoz/CNW breather.

Is your bike an early frame bike with the cross member that interferes with the sump breather??? If its a later frame, why not just get Jim's bolt on sump breather and call it good??... no modifying, just bolt it up...

gortnipper · Jul 8, 2015

o0norton0o said:
gortnipper said:

o0norton0o - that is a bit more adventurous than I would be for this. If I was going to do that much work, I would do the Comnoz/CNW breather.

Click to expand...

Is your bike an early frame bike with the cross member that interferes with the sump breather??? If its a later frame, why not just get Jim's bolt on sump breather and call it good??... no modifying, just bolt it up...

OK - so I was not aware of his sump breather. It looks good, and it might be my "permanent" fix if they are still available.

Still interested in understanding the Mike's breather to case distance/condensation issue. One of the primary reasons I initially liked the high mounting is that oil could either drain to the catch can or back down to the case when the engine was off.

Snorton74 · Jul 8, 2015

o0norton0o said:
gortnipper said:

o0norton0o - that is a bit more adventurous than I would be for this. If I was going to do that much work, I would do the Comnoz/CNW breather.

Click to expand...

Is your bike an early frame bike with the cross member that interferes with the sump breather??? If its a later frame, why not just get Jim's bolt on sump breather and call it good??... no modifying, just bolt it up...

+1. I'm sure they're available. Just PM him and he'll set you up with one.

texasSlick · Jul 8, 2015

gortnipper said:
Still interested in understanding the Mike's breather to case distance/condensation issue. One of the primary reasons I initially liked the high mounting is that oil could either drain to the catch can or back down to the case when the engine was off.

High mounting the XSValve to drain oil to the oil tank (past the reed) and back to the cases (in the tubing before the reed) is a valid consideration and one which I mulled over for some time. I think the high rpm pumping losses that happens with a length of lead-in tubing, leads to higher pressures in the crankcase and are a greater concern. Any oil which pools in the body of the XS valve and the tubing after the reed will be forced into the oil tank as it is with Jim's sump breather. Pooling oil in the XS body will likely require some clean up maintenance from time to time. This maintenance will likely be less if the valve drained to the oil tank.

The whole point of the XS valve is to minimize crankcase pressure. Mounting it as close to the crankcase as possible will result in lower pressure, but somewhat more maintenance.

Slick

nortonspeed · Jul 10, 2015

My XS breather valve is mounted high next to the oil tank breather connection and the central frame tube, approx. 5" hose to the oil tank and 2ft hose from the crankcase (back of the timing cover). This is not really a short line as it runs under the battery tray but it works and have no condensation issue at all.

swooshdave · Jul 10, 2015

texasSlick said:
gortnipper said:

Still interested in understanding the Mike's breather to case distance/condensation issue. One of the primary reasons I initially liked the high mounting is that oil could either drain to the catch can or back down to the case when the engine was off.

Click to expand...

High mounting the XSValve to drain oil to the oil tank (past the reed) and back to the cases (in the tubing before the reed) is a valid consideration and one which I mulled over for some time. I think the high rpm pumping losses that happens with a length of lead-in tubing, leads to higher pressures in the crankcase and are a greater concern. Any oil which pools in the body of the XS valve and the tubing after the reed will be forced into the oil tank as it is with Jim's sump breather. Pooling oil in the XS body will likely require some clean up maintenance from time to time. This maintenance will likely be less if the valve drained to the oil tank.

The whole point of the XS valve is to minimize crankcase pressure. Mounting it as close to the crankcase as possible will result in lower pressure, but somewhat more maintenance.

Slick

Which is why I drilled a small hole next to the reed valve. This allows oil to drain back down to the sump, in case it gets trapped.

xs650-breather-exposed-t7345.html

N0rt0nelectr@ · Jul 10, 2015

Where did you acquire the breather? I would think your local Yamaha dealer wouldn't stock it after all these years?

John in Texas

Mounting Mike's XS reed breather

gortnipper

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