Catch bottles?

Assembling a fancy one for my oil tank vent hose to go in to. Nice go-kart ones on ebay for $16. Unsure where to put it though.Thinking of putting some kind of a clamp on the bottle (2") and one on the frame some where. Anyone know the frame diameter of the Commando so I can find some nice machined clamps?
Standing upright the drain tap will be at the bottom,air filter straight out of the top and the vent hose in to the fitting below it

Why does it not just go to your oil tank?

Thank goodness niether my buddy nor my Cdo's dripped out oil tank breathers so seems just a cool decorative piece to me. Some do excrete oil so if was mine I'd think the best place would be mounted on rear frame tube behind oil tank.

swooshdave said:

Why does it not just go to your oil tank?

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This is the vent from the tank. originally it went back in to the carbs (32-40) but that was all removed by the PO

Nice piece. It will allow oil fumes to condense and whatever doesn't to be burnt, without fouling your air filter.

It used to be that one of the sources of oil leaking out of my Commando was the bottom of the air filter. The air filter/air box being the outlet for the oil tank breather of course. High RPM blow by coupled with oil tank sloshing I'd guess. Then too, keeping the oil topped off, sometimes overfilled, caused this as well.

Mine has always dripped a bit out of the oil tank breather (central oil tank). I did this, but it means I have to take off the carbys to get to the air filter, but that happens anyhow, so it's just not a big deal to me. A little oil goes a long way when it drips down on top of the gearbox and eventually finds its way all over the rest of the bottom.



Dave
69S

Dead right DogT. Short cruising trips trips no problem but after a 600mi trip recently there was oil film everywhere. Cant say it was the breather hose for sure but I want to eliminate it from the equation permanently

So this is the breather for the oil tank? If it's pushing out that much oil are you sure you don't have another problem? Like excess oil?

I have a round plastic soap bottle that I use for a dump can, its a 2 litre bottle and it sits nicely between the engine mounts just behind the gearbox but my engine mounts are longer as my 850 sits in a Wideline Featherbed, it's very hard to see and hides well, I run my motor breather straight into the top of the bottle as well as my oil tank breather, the hoses sit about 1/4 of the way inside the bottle and there is enought space from the bottle top to let air in or out of the bottle, I mite empty the bottle once a year but it nomaly only has about 200cc or lest, I find the bigger the bottle the better it works, I have been using this set up for over 30 years now and never had any issues with oil blowing over my Norton.

Ashley

I think you'll find it really helps. Mine did, it was phenomenal, and I haven't even dumped the oil in 1K miles. There may be 1/4" of oil in that pill bottle, but that stuff spreads like horse dukie.

Dave
69S

swooshdave said:

So this is the breather for the oil tank? If it's pushing out that much oil are you sure you don't have another problem? Like excess oil?

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Correct,the breather for the oil tank. Eliminating one thing at a time looking for source of oil. I keep the oil level in the tank just above the low mark on the dip tick and it doesn't wet sump a whole lot.

Hey DogT
I've been admiring your pill bottle idea for some time now - my bike has the central oil tank too - but I was wondering how to come up with something that looks a bit more, er, automotive.
Thanks to speirmoor I can stop wondering. It really looks the part. This forum is great.
Cheers
Martin

MFB, Let me know how you work it out. I'd like something a bit more pro looking myself, it was just quick, dirty, cheap and effective. It probably wouldn't fit inside the air filter, or the input may be above the tank port if you could put it in the filter. I think it would be not good to have that breather line go up at all. Maybe it could fasten to the chrome front piece? Hmmm.

Dave
69S

OK speirmoor, where did you get that bottle, I've been looking all over and can't find it. Was it a one time item?

edit
got it 310418331666

Actually that catch bottle looks a bit small for what I have in mind.
I'm working towards adding timing case breathing to the timed camshaft breathing. I'm sure someone mentioned doing that in a thread I read a while ago.
I think the NOC service notes also talk of this modification (2 breathers). That's what started me thinking of engine breathing in the first place, and before I discovered this forum and Jim Comstock's excellent work with Nortons.
As an aside, because my bike has been converted to the cradle mounted centre stand, I could have (and still could) cut out the cross tube to make room for a sump breather if I had to.
( I added another cross tube at the front as part of my sidestand upgrade).

What I have in mind is:

Routing both breathers to a catch tank.

Allowing the oil tank to breathe to the catch tank via the port formerly used for the camshaft breather.

Plugging the original oil tank breather - the one that goes into the air filter.

They're only thoughts for now. I'll post updates when things take shape.

My bike used to stay pretty dry, but I didn't want to do this rebuild without making the most of the opportunity. I don't think I'll be stripping it down again (I hope).

Cheers
Martin

The bike is on its wheels now and it's time to attend to the oil tank/ breathing issue.
I've decided against the idea of having two crankcase breathers; I want to try the Mike's XS breather on the timing side (I drilled the necessary holes during the rebuild, and tapped them for plugs just in case it didn't work).
I think now that leaving the camshaft breather in place would tend to dilute the pulses going to the reed valve, so I'll plug it as others do. This will also make for a neater look.

So the new plan is:

Route the timing side breather to a catch tank. (I have yet to source a suitable one).

Allow the oil tank to vent to the catch tank via the port formerly used for the camshaft breather.

Plug the original oil tank breather - the one that drips oil into the air filter.

Vent the catch tank into the front of the air filter. Sort of Dave's setup in reverse. It shouldn't drip oil. If it does I'll vent it to atmosphere.

I read a comment recently that routing the crankcase breather to the oil tank is less than ideal as it directs blow-by contaminants into the oil, but it was an expediant used by Norton and others. Makes sense.

BTW I ended up having to cut the old cross tube out of the frame, it was touching the cradle when the bike was on its wheels. I'm sure it didn't do that before the rebuild, but I was probably looking at it with the bike on the centre stand - d'oh.

Cheers
Martin

I got a good looking catch can from a go-kart place. I'll see if I can find the link, it was only about $20, solid AL and 3 ports with connectors, but the connectors are smaller than 3/8". It's a bit small, but I'm using a large pill bottle and so far have not gotten more than about 1/4" of oil in it, but that's from the oil tank breather. I think I found it on ebay, but it's available right from the dealer too, someone posted a picture of it a while ago.

edit: oops, the pic and link are at the beginning of this thread.

Dave
69S

I just bought 4 foot of 3/8 line yesterday. I am going to ditch my catch can I placed in favor of a overflow tube to the end of the bike. I overfilled my tank and it flowed out into the bike, pissed me off....

I see this happening again since I am horrible at reading my dipstick.

heres how I got it now. I used a can o' beans without the label. It works until i overfill my tank to the point it overflows the can! I bought a coo looking catch can but I dont think Im going to install it.

Nothin' wrong with a can o' beans ,whatever works for you and remember it's made of tin (brits), so it's kinda authentic. How were the beans ? Over a campfire always the best with bacon eggs n' toast n' coffee. Also keep the oil level just above "L" and no worrys .

Torontonian said:

Nothin' wrong with a can o' beans ,whatever works for you and remember it's made of tin (brits), so it's kinda authentic. How were the beans ? Over a campfire always the best with bacon eggs n' toast n' coffee. Also keep the oil level just above "L" and no worrys .

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that "just above L" freakin bit me! I went to go for a ride and decided to run my bike at idle for a few min then checkthe oil.... I checked it and decided to fill it to just above L and that seemed fine. Then I got down the road about 5 miles and noticed that can o beans was splurging all over. ugh I guess the idle in the garage was not enough to get my oil tank to the propoer level for reading the dipstick. I am now just reverting to running the tube to the lic plate and letting the one folowing me get any leftovers!