A Miracle - no more engine oil leaks!!! (Mark III)

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Ok, I admit it - I was a big time skeptic.

I had read a few posts here and there about using an inexpensive check-valve in the breather line from the timing case to the oil tank, which would supposedly help reduce pressure in the engine from slightly positive to slightly negative.

Sure, sure, and Santa is going to bring me all kinds of new chrome parts too.

But I was tired of the never-ending oil seepage from the base gasket area, and other mysterious sources that I could never seem to really pin down, so I decided I didn't have much to lose, other than a few bucks. I bought two of the recommended check valves
1) the Motormite/HELP 80190 check valve (I paid $2.54 from an online auto parts supplier)
2) the Yamaha XS breather PVC valve (part # 15-0677 from Mikes XS, cost = $15.00)

I didn't have a convenient place to mount the Yamaha breather valve, so opted for the simpler inline installation of the plastic Motormite check valve

Much to my delight and surprise - the oil seepage stopped! Amazing! I am now a believer.

Now I'm ready to tackle that mysterious leak from underneath my primary case somewhere....

Hey, I wonder if this same check-valve approach would work for Triumphs. I was at a little event this week with about a dozen old Triumphs, all of which had been washed and polished that day, and all of which had fresh oil oozing out various orifices from the head on down. Should somebody tell them?

Keith - oil free in Encinitas
 
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You'll probably find that the Motormite valve gives up rather quickly. It's designed for a vacuum brake. Now that you've proven to yourself that the oil leaks are coming from a pressurized crankcase you'll probably want to invest in a proper inline breather valve. There was one, besides the Yamaha, mentioned here a few weeks ago. It was about six times the cost of the Yamaha valve, seems it had something to do with Harley Davidson. Oh, BTW, when you installed the Motormite did you notice any increase in power? You'll pickup up a horse or two. Engine is not working to pressurize the crankcase.
 
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Jim -

When you say the Motormite valve "gives up rather quickly".... how long (or "quickly" are you referring to?

A month? A year? 5,000 miles? How long has it lasted for you?

At this price, and my avg mileage of about 3,000 miles a year on the Commando, if I had to replace the Motormite check valve once a year, it would still be a great deal (plus the fact that I don't have to fight for mounting space for it).

PS - didn't notice any increase in power. I find this a pretty subjective thing anyway. People swear (myself included) they find an increase in power with all kinds of little tweaks. Personally, I find my bike runs so much better right after I give it a wash and a shine - especially on a nice sunny day.

Keith
 
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The person that wrote the article, Breather Valve Fixes Oil Leaks! that is on the INOC and NOCNC (he lives in the Bay Area) websites told me that he has not really seen one of these brake valves give up. My initial thought was that they would get fouled with oil eventually and become useless but he said that this doesn't seem to be the case. I agree that these little brake valves are great for doing what they do and if you would need to replace them once in a while then so what.
 
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Keith

I say NOthzin~

I have been advocating this adaptation for some years now and in fact lay some claim to being one of IF not the first.. and as far as I am concerned I worked this one out all on my lonesome ~

And using a PCV from a six cylinder car , I have some reservations about any comment regarding the thing wearing out !!
:shock:

(Oops I did say something ~ :roll: )
 
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"Now I'm ready to tackle that mysterious leak from underneath my primary case somewhere..."

i recently fixed all the leaks coming from my primary area. check it out...

the grommet that the stator wires pass through was rock hard and the felt seal at the trans shaft was worn.

A Miracle - no more engine oil leaks!!!   (Mark III)
 
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You'll pickup up a horse or two. Engine is not working to pressurize the crankcase.

Intriguing thought.. completely logical too ~

Hey, I wonder if this same check-valve approach would work for Triumphs
.

I believe the reason this is so effective on Commandos is that they have the long stroke ~

But given the existing set up on any machine unless the breather is the size on the tail pipe, any engine would benifit ~

I am thinking of fitting one to my project T150V (or affectionatley named "JJ" ~ after the engine number.)

But if it is anything like my T160~ it won't leak oil ~ full stop ~ 8)
 
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iusedtolikehondas -

Felt seal on the trans shaft? I haven't taken off the primary case yet, but from poking my head under, it looks like i have a leak from the shaft/ sprocket area.

Sure looks like the primary case oil coming out (I checked the level in the gearbox. It is where it is supposed to be and has been at that level for months).

My question is: what felt seal on the trans shaft? I was looking at the diagrams on the oldbrits site and can't figure out what you mean. And if it was that seal causing the problem, it would be gear oil coming out, not the oil from the primary case, n'est pas?

Appreciate any insights

Keith Kelly
 

Ron L

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Keith,
You have a Mk3 which makes you "special"! :lol:

The Mk3 has a fixed transmission mount and so uses a genuine lip seal (P/N 065956 1.125X1.875X0.375) in the primary case to seal the input shaft. If you are leaking from this area it is probably this seal that needs replacing.

Earlier models had a sliding disc arrangement to allow the transmission to move for primary chain adjustment. These discs sandwiched a felt seal to keep oil in.

If it is gear oil, it would be the sleeve gear seal on the transmission (P/N 040132)
 
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Ron -

Thanks for the "special" designation. I saw the "Oil Seal, Inner Primary, (P/N: 06-5956)" on the diagram on OldBrits site and was guessing this was the probably the item to replace.

Thanks for the confirmation. Just ordered it ($5.80).

Will see if this stops (slows the leakage). Will also dab some silicone around the hole where the alternator leads exit the inner case.

Keith Kelly
 
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breather valve

Anyone in the UK fitted one of these valves or similar?If so where did you buy it and where did you fit it?
 
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Pumping in a Norton crankcase would be particularly bad with the 360 degree firing. Haven't had a Triumph twin apart but I believe they are 180 or 270 degree cranks which has less volume change in the crankcase.
 

grandpaul

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Triumph twins are 360 degree firing from way back in the 30s till the very end in the 80s.

That lump is similar to the chevy 350 in that it "wasn't broken" for 50 years, so they didn't fix it much.
 

MichaelB

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pkeithkelly said:
Ron -

Thanks for the "special" designation. I saw the "Oil Seal, Inner Primary, (P/N: 06-5956)" on the diagram on OldBrits site and was guessing this was the probably the item to replace.

Thanks for the confirmation. Just ordered it ($5.80).

Will see if this stops (slows the leakage). Will also dab some silicone around the hole where the alternator leads exit the inner case.

Keith Kelly

Careful alignment of the inner case is very important.
Set up properly, it will be leak free.
 
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Commando 1954.......you can get a jumbo brass item from Norvil with whatever size barb adaptors needed for the pipe you have 3/8" early Commandos, p/n 069902 and 1/2" for the Combat and 850 fittings, p/n 069903. It is a lump though and fits in the breather line to tank neck. Usual place is vertical next to the battery. It won't cure a motor with shot rings but will cleanup an engine in normal condition. It simply takes the strain off the joints by reducing pressure in the cases..............air and oilmist goes out and can't get back in. There is the famous Motormite brake booster valve available in the US but you'll have to do a search for that.
 
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I'm in the UK.

I went to a scrap yard and pulled the valve off the front of a Volvo brake servo. It works fine.

It was already at least 10 years old!

I looked at a variety of other models, there only seems to be two types, and the sizes work fine with the Commando pipes.

Alex
 
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Commando 1954 - I fitted one of the 'jumbo' Norvil units - yes it is big but there are various sizes dependant on your engine size - mine's a 920 so I've got a big one (so to speak !!). I mounted the unit vertically just ahead of the oil tank (I have just one single Mk2 Amal carb thus there is sufficient room to locate the valve in that position). Subsequent to fitting it I have NO oil leaks from the engine (having said that it was pretty good prior to fitting). If you do buy one of these beware of one issue - when I unpacked it I tried to blow through it (with 'lung pressure') and got nothing - I thought this was not right and thus poked a small wooden stick into valve - I heard a 'click' and subsequently I could blow the valve open quite easily. The valve ball had obviously stuck - if I had fitted it to the engine in that state I don't know what would have happened.

hth.
 
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Oil Leaks!!

About 7 years ago, a buddy pulled his Triumph apart, and while it was down I ground a groove aall the way around any flange were oil would go prime, gearbox cases etc, about 120 thou deep, with a pencil grinder, the cases I grooved both sides, kinda tricky, do one side, then put masking tape on other side, then spotting blue on masking tape, put them together, snug them up then tap with soft hammer, leaves line from groove cut, then when assemble use good RTV silicone, Gold? that bike does not leak to this day, will do it with my Commando when I start work on it. O I used a 125 thou carbide burr, couted with beeswax to stop clogging
 
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