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#84003 - 10/01/05 7:06 am Oil leaking from breather tube
thesurfer Offline
BritBike Forum

Registered: 09/30/05
Posts: 19
Loc: Stockholhm, Sweden
My 1961 Bonneville has started to leak oil from the breather tube. I have checked to make sure that the pump is scavenging (both oil tank level and there was <100ml in the sump). I have removed and cleaned the new Morgo plunger oil pump several times and have not found anything in it. I have been searching for a solution on the internet and it seems to be an engine tear down to check the breather valves.

Before I tear down the engine this winter to get at the breather valves does anyone have any suggestions?
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#84004 - 10/01/05 9:46 am Re: Oil leaking from breather tube
Tiger Offline
BritBike Forum member

Registered: 10/26/04
Posts: 4429
Loc: Melbourne Australia
I know bugger all about the breather arrangement on the PU bikes but assume it is the same as the unit pre 70 650, that being a rotary valve on the drive side end of the inlet cam ?

I have only stripped three engines fitted with that system but none have shown anything but the slightest wear in the disc valve, I would not bet good money that you have a problem there.

When I obtained my current unit 650 it passed quite a bit of water and oil emulsion through the breather, bike ran well and did not use hardly any oil but ring gaps and radial ring thickness were beyond tolerances, new rings cured the water breathing.

Is it possible that oil is coming out of your tank breather ?
If you fill the tank to the full mark with a cold engine oil level will rise as warm aerated oil is returned to the tank, this will vent through the tank breather and there will be lots of it.

My '69 has a dipstick attached to the filler cap and correct cold fill is approx 1/4" below the full mark.

I am not running the std '69 breather pipework arrangement, IMHO it is a bloody mess, you do not need to know why as you are unlikely to think of something so silly, however others may wonder.
_________________________
1969 TR6R
7.62 x 51 is not a maths puzzle.

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#84005 - 10/01/05 12:32 pm Re: Oil leaking from breather tube
thesurfer Offline
BritBike Forum

Registered: 09/30/05
Posts: 19
Loc: Stockholhm, Sweden
No, there is nothing coming out from the tank. The 'drip' is coming from the crankcase breather. Not that much but still messy.

I had the engine completely rebuilt by P&B Choppers in Göteberg and the head done by Len Paterson at the Cylinder Head Shop in the U.K. less that 1,000km ago. It was running fine (really well actually) and no drip with the new Morgo plunger pump. But alas, the Gods of Triumph decried that you should have to work on them and not just ride it. So at speed it bent a push rod and blew a hole in the piston. It was been completely rebuilt since then and back on the road recently. Of course it could be something in the scavenge system coming up from the sump that we missed.
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#84006 - 10/01/05 6:05 pm Re: Oil leaking from breather tube
RF Whatley Offline
BritBike Forum member

Registered: 10/29/03
Posts: 10025
Loc: The sunny South
Surfer Dude -
Oil dripping from the breather tube is normal on a Triumph. These bikes were never oil-free and always have one or five spots on the floor after a ride. If you were raised on Hondas, buy a cookie sheet to put under the bike.

Excessive oil blowing out the breather is never the problem of the timed breather valve. That's like blaming your nose bleed on your nostril. The valve is only the portal the oil uses to escape. There is no "oil catch" on the breather.


If you think you have excess oil then try these items...

1) The location of the breather hose near the c/s sprocket leaves it exposed to grit that eventually wears a hole in the tubing. Oil normally present inside the tubing will then leak out making it look like a new issue, when in fact the oil has been there all along. So replace the tubing. Lowes home stores sell some really nice black, thin-wall vinyl tubing that is great in this application. And then plan to replace the tubing every 2 years thereafter.

2) Excessive (5-12 oz) oil blowing out the breather could be an oil wet sump issue. Drain the sump and measure the amount of oil. It should be in the 1-2 oz zone. If not, clean out your return-side oil pump. The procedure has been beat to death here many times. Look around.

3) If the amount of sump oil is correct, the last cause is simply too much piston ring blow-by, usually caused by excessive ring end gap. This usually is an indicator that you need a bore job with new pistons and rings to get the fit back to standard. HOWEVER, numerous measurements need to be made before the decission should be made to bore or just to replace the rings. You should really make these yourself and then see if they match your mechanic's measurements.

Mechanics always make more money on big jobs, so they'll always insist every removed cylinder needs a bore job; every removed head needs a valve job. $1000 later you'll still have those 2 to 10 drips.

Most of the time you'd be much better off simply sending me the money. :rolleyes:


bigt
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#84007 - 10/02/05 4:55 am Re: Oil leaking from breather tube
thesurfer Offline
BritBike Forum

Registered: 09/30/05
Posts: 19
Loc: Stockholhm, Sweden
RF, thanks for the input. I have had this bike for 33 years now and realized long ago why Triumph went out of business. Before the last overhaul I mentioned above, I did have a baby bottle mounted about the height of the oil tank that caught the 'drip' from the crankcase breather. However, when I rebuilt the bike last I removed that.

I was wondering if it is possible to modify the oil tank and route the breather tube back into the oil tank and then only have the oil tank breather venting the engine. I would suspect that it would work well, as I had no problem pushing oil through the breather tube to the baby bottle I had mounted before. This would provide a rather clean solution to problem. Has anyone tried that?
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#84008 - 10/02/05 6:54 am Re: Oil leaking from breather tube
Tiger Offline
BritBike Forum member

Registered: 10/26/04
Posts: 4429
Loc: Melbourne Australia
Yep, a company by the name of "Triumph Engineering Co did just that, it is the factory '69 breather arrangement that I was complaining of.
The std setup actually runs the engine breather into a tee piece just off the tank breather, the tank breather hose then runs back and exits under the rear 'guard.
The issues I have with the arrangement are firstly why would you want to risk pumping blowby condensation back into the oil tank and secondly the fluid lock that forms in the low point of the engine breather tube.
This caused minor oil leaks on my TR6 specifically oil misting past the drive side end of the rocker spindles.
_________________________
1969 TR6R
7.62 x 51 is not a maths puzzle.

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#84009 - 10/02/05 8:05 am Re: Oil leaking from breather tube
thesurfer Offline
BritBike Forum

Registered: 09/30/05
Posts: 19
Loc: Stockholhm, Sweden
Tiger, good response. I also have the same questions. But, when I had the breather running into the baby bottle, I didn't experience fluid lock or any more leaking from the engine (except the breather tube) than before. Of course, I just poured out the collected oil in the baby bottle every now and then.

I suppose to be really practical a fully developed PCV type of solution like on car engines is required.
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#84010 - 10/02/05 9:17 am Re: Oil leaking from breather tube
Tiger Offline
BritBike Forum member

Registered: 10/26/04
Posts: 4429
Loc: Melbourne Australia
Crankcase breathers are an interesting subject and apparently a lot of work has been done by race engine builders.
One thing is sure and certain and that is that a breather cannot vent all that the pistons displace otherwise our little breather hose would have to pass 4.25 cubic metres per minute at redline. eek

The timed breather seems to be a good setup for the 650's, Triumph only abandoned it when the 750 engine was in prospect but the change may have had something to do with emission standards also.

British twins present unique problems, a jap 180deg twin has one piston rising whilst the other decends so crankcase displacement is theoretically equalized, not so with our engines.
_________________________
1969 TR6R
7.62 x 51 is not a maths puzzle.

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#84011 - 10/02/05 3:23 pm Re: Oil leaking from breather tube
keith100 Offline
BritBike Forum member

Registered: 10/23/03
Posts: 125
Loc: Toronto
Panic

I don't know about timed breathers, but on my 72, with a simple pipe, I assume it lets air pressure out of the c/c as the pistons fall and lets air in to fill the vacuum in the c/c as the pistons rise. Is this right?

If you place a PVC into a breather pipe left open to the air at the end, won't you prevent the relief of the vacuum and screw the system royally?

PCV valves on cars are routed to the intake manifold and kept permanently open by the vacuum. I thought they were designed just to suck any blow-by fumes out of the crankcase, not relieve any pressure.

Keith

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#84012 - 10/02/05 4:11 pm Re: Oil leaking from breather tube
RF Whatley Offline
BritBike Forum member

Registered: 10/29/03
Posts: 10025
Loc: The sunny South
Meanwhile back at the original topic.....

Surfer Dude et al -
The BEST breather solution was offered by the last Nortons. That is, route the engine breather directly back to a high point on the oil tank. Then, from a different additional HIGHER point on the oil tank, a second hose goes out the rear fender or down to the ground.

The pre-1970 Triumphs used a Y fitting in their breather line so as to only have to weld on a single oil tank breather. This was unfortunate since any small dia engine breather is always going to "blow" enough to carry some oil mist with it. That mist deserves to be back in the tank. Thus Triumphs before 1970 with the small dia breather are always driping 1 or 2 drops from the breather hose end.

Triumph addressed this quite well with their post-1970 primary breather design. The large primary case slows the velocity of the breather blast down so much that the mist drops out. So the breather on those is 99% mist free until the rings go bad.

An oil tank has its own issues. Most of the water created during combustion is captured in the engine oil. Every oil tank therefore has to be free to breathe to allow the water vapor to "cook off". So that kills the idea of simply connecting the engine breather to a Triumph oil tank with a single hose and calling it quits. The water would collect in the tank until a sufficient amount was present to be pumped to the rod bearings... and end of story.

PVCs are another story. Let's stay on topic, lads.

bigt
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RF Whatley
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#84013 - 10/05/05 6:08 pm Re: Oil leaking from breather tube
scootermcrad Offline
BritBike Forum

Registered: 04/06/05
Posts: 441
Loc: Huntington Beach, CA
Surfer guy...
If it makes you feel better, I have the same drip from the same tube bigt The engine was just rebuilt, it runs great, yet.... still a leak. As of now I haven't worried about the solution because it hasn't created much of a problem and I haven't had a huge amount of oil coming from the tube. I simply put an old towel under it and let it go. HOWEVER, this doesn't really answer your question, it only reinforces your question. I've been thinking of a small, transparent bottle with a small filter on top to allow breathing, yet would let me see the level of oil in the bottle. Plumb a small drain cock in the bottom and drain it out every now and then. If you put the bottle between the tranny and crank case, then you can view the levels.

Just and idea I've been kicking around in case things get out of control. In the mean time, I've just come to accept that my Triumph must mark it's territory. smile Let us know if you come up with something. This has been brought up here in the past and I don't think a conclusion was ever reached...
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#84014 - 10/06/05 12:46 am Re: Oil leaking from breather tube
trumpetloon Offline
BritBike Forum member

Registered: 11/10/04
Posts: 1694
Loc: georgia
RF.. listen to Keith100 and Panic... they speak sensibly. The vent is there to relieve excess crancase pressure, obviously. They just explain the process so the less experienced among us can comprehend. Your insight may help resolve the problem, but the other guys were indeed on topic with the discussion of automotive style crankcase ventilation. The object seems to me to allow as much outside air into the cases as is practical, then devise a means to capture any overage. BTW surfer... a leakdown test may yet validate the ring end gap theory! beerchug
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1974 TR5T

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#84015 - 10/06/05 5:35 pm Re: Oil leaking from breather tube
dave jones Offline
BritBike Forum member

Registered: 10/10/03
Posts: 3125
Loc: Emsworth, sunny south of Engla...
I get a drip or two of emulsified oil from my breather pipe too. I have the full set up on my '67 but have installed a drain into the lowest loop which I open occasionally to drain out the gunge. It is normal for oil and water to come out. I don't think you need worry about anything going back into the tank. These bikes have been running like this for decades.
Dave

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#84016 - 10/06/05 5:37 pm Re: Oil leaking from breather tube
dave jones Offline
BritBike Forum member

Registered: 10/10/03
Posts: 3125
Loc: Emsworth, sunny south of Engla...
I get a drip or two of emulsified oil from my breather pipe too. I have the full set up on my '67 but have installed a drain into the lowest loop which I open occasionally to drain out the gunge. It is normal for oil and water to come out. I don't think you need worry about water going back into the tank. It is not likely and once you are running up to temerature it would come out straight away anyway. These bikes have been running like this for decades.
Dave

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#84017 - 10/07/05 4:16 pm Re: Oil leaking from breather tube
RF Whatley Offline
BritBike Forum member

Registered: 10/29/03
Posts: 10025
Loc: The sunny South
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by trumpetloon:
<strong> RF.. listen to Keith100 and Panic... they speak sensibly. The vent is there to relieve excess crankcase pressure, obviously. They just explain the process so the less experienced among us can comprehend. Your insight may help resolve the problem, but the other guys were indeed on topic with the discussion of automotive style crankcase ventilation. The object seems to me to allow as much outside air into the cases as is practical, then devise a means to capture any overage. BTW surfer... a leakdown test may yet validate the ring end gap theory! bigt
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RF Whatley
Atlanta, GA
http://www.gabma.us/

The GABMA newsletter. What's on the back of your toilet?

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#84018 - 10/07/05 5:49 pm Re: Oil leaking from breather tube
cycarmark Offline
BritBike Forum member

Registered: 08/16/01
Posts: 286
Loc: florida
RF,

Where do you get these metal jacketed PCV valves, and should they be used in conjunction with the timed breather? I've got a '69 TR6C, a '70 A65 and a '59 3TA that could use such a modification.

Thanks

Mark

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#84019 - 10/07/05 6:58 pm Re: Oil leaking from breather tube
dave jones Offline
BritBike Forum member

Registered: 10/10/03
Posts: 3125
Loc: Emsworth, sunny south of Engla...
I don't have a pcv valve. Where should my bike be leaking oil from??
Dave

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#84020 - 10/07/05 9:24 pm Re: Oil leaking from breather tube
Aloniw Offline
BritBike Forum

Registered: 06/29/05
Posts: 121
Loc: Portland, Oregon
I use a metal in-line pcv from Honda, it's length is 44.7mm, the small end fits the stock breather tube correctly, but you would have to use a section of larger tubing at the opposite end (13.1mm)with spring clamps, but that's no biggie at all.
I'm using this valve on a '68 T120 in conjunction with the rotary timed breather with good results (so far), in the vertical section of the breather hose just below the 'T'.

Honda Car P/N 17130-PE0-003 current price: $16.10

Aloniw

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#84021 - 10/10/05 2:10 am Re: Oil leaking from breather tube
RF Whatley Offline
BritBike Forum member

Registered: 10/29/03
Posts: 10025
Loc: The sunny South
Quote:
Originally posted by cycarmark:
Where do you get these metal jacketed PCV valves, and should they be used in conjunction with the timed breather? I've got a '69 TR6C, a '70 A65 and a '59 3TA that could use such a modification. Thanks, Mark
I use the all metal ones from NAPA for about $4. These are general use PCVs and are usually hanging on the formed-wire spinning display stand in the showroom. They are labeled as their Echlin brand. There are 3 or 4 hose size selections, with the same general straight-through design for each.

One thing you need to know is that some PCVs work on gravity alone while some have a spring. The Echlin models have NO spring and therefore need to be near vertical to work properly. On a Triumph that means they have to be placed in the breather line as it runs vertically up the frame tube, just in front of the battery.

To hide mine, I used 4 or 5 passes of safety wire to make a very low profile hose clamp on either end. Then I slipped a 4" long piece of 1" dia black heat shrink tubing over the PCV and shrunk it. You almost have to touch it to find it. It's very well camouflaged.

Will they work with a timed breather in place? Well, they certainly couldn't make one work any worse! bigt
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Don't hide 'em, Ride 'em !!

RF Whatley
Atlanta, GA
http://www.gabma.us/

The GABMA newsletter. What's on the back of your toilet?

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#84022 - 10/11/05 8:09 am Re: Oil leaking from breather tube
thesurfer Offline
BritBike Forum

Registered: 09/30/05
Posts: 19
Loc: Stockholhm, Sweden
Wow! Thanks for all the ideas.

I know the bottle idea works because I did that before. The baby bottle was a good converstation started too. Feeding it back into the oil tank has some advantages also.

The PVC valve seems like a good idea to experiment with. Thanks for the details on the NAPA item and the Honda info, I will pick one up next week ;-)

I will let you'll know the outcome.
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#84023 - 10/11/05 8:56 am Re: Oil leaking from breather tube
Tiger Offline
BritBike Forum member

Registered: 10/26/04
Posts: 4429
Loc: Melbourne Australia
A little puzzled at references to the inadequacy of the timed breather to cover the job at varying engine RPMs'.
Long cam timing at high revs is viable because of the compressive [inlet] and extractive [exhaust] effect of the mass of gas at high velocity.
Gas at the breather disc is essentially stationary until the disc begins to open then must accelerate under the force of crankcase compression, any extractive effect in a 3/8" bore breather hose would surely be minimal.
Fixed breather timing, relative to engine revs, would appear to be identical whether or not a disc valve of poppet check valve is used ?
Also not sure that a poppet type valve would function efficiently at 108hz [redline of 6500 RPM].
It probably does not matter, the job of either is to compensate for ever present blowby and ideally maintain average crankcase pressure at slightly below atmospheric.
_________________________
1969 TR6R
7.62 x 51 is not a maths puzzle.

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#84024 - 10/11/05 4:32 pm Re: Oil leaking from breather tube
dave jones Offline
BritBike Forum member

Registered: 10/10/03
Posts: 3125
Loc: Emsworth, sunny south of Engla...
Don't worry Tiger, no one ever rides their bikes, let alone revs them to the red line! wink

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Untitled Document

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