Leaky Breather

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CANbus
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Hi Guys.

Like most I guess I fill the crankcase with oil just until oil starts to flow out of the second crankcase plug.
However try as I might I’m unable to stop the breather from leaking. I have tried at least 4 different breathers including an original one. All pass the blow test. I wondered if anyone had any tips or tricks?
I can’t help but wonder if the second plug level is just to full? Was there ever a published oil quantity that should be put in the crankcase

Thanks.
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rosscla
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Most of the books say 700ml, but camlam recommend 500ml

http://www.lambretta.co.uk/faq.html

You can put too much in if the stand isn't level or the bike leans to the near side.
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Donnie
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Always used 500ml on an oil change but 700-750 on a completely dry build to include soaking the plates.
Never had a problem yet.
Donnie.
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ForemanBob
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When you say that the Breather is leaking, do you mean that oil is coming out the top of the breather hole.

If so, it sounds like your chaincase is pressurised from the crank-side oil seal?

It may be that the oil seal is worn, and pressurising your chaincase side, or that the Oilseal has been fitted the wrong way round (i know this one from personal experience :oops: :oops: :oops: )
bristolmod
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it could simply be the transfer of oil from the chain whilst the engine is running. Oil is thrown everywhere by the transmission, and inevitably some makes contact with the breather plug area. Is the breather plug in good shape? i.e. does it "breath" OK, but does it also have the little piece of gauze that stops, in theory, oil being thrown out via the breather hole?
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CANbus
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Thanks for all the input, having read the comment on Camlam, in my case I think I may have just too much oil in. I will put in 500ml and see how it goes.
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bristolmod
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as an aside, I worked for a scooter dealer a few years ago.

A guy came in and said his Lambretta wasn't running very well, and could we look at it.

Upon inspection, we found that he had misunderstood the oil level instructions, and, instead of stopping filling with oil when the level reached the 2nd drain plug, he thought he had to stop when it reached the filler / breather plug...............

I think he managed to get well over 2 litres in............

Chris
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CANbus
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ForemanBob wrote:When you say that the Breather is leaking, do you mean that oil is coming out the top of the breather hole.

If so, it sounds like your chaincase is pressurised from the crank-side oil seal?

It may be that the oil seal is worn, and pressurising your chaincase side, or that the Oilseal has been fitted the wrong way round (i know this one from personal experience :oops: :oops: :oops: )
Ok, tried four different breathers one off the 1964 li s3, about three types of oil, all SAE90.
If it were a seal would there be others symptoms, the oil drained out looks ok, ie no signs of petrol contamination.



The engine is new done about 600 miles running in with no problems, i paid a small fortune for it.
I'd be devasted if I have to strip it down. :(

Thanks
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blue
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I'd imagine if it's a drive side oil seal problem you'll be burning gearbox oil resulting in loads of smoke from your exhaust.
Any idea what size front sprocket you're using?
I use 20 & 21 tooth sprockets and had the same issue using a push up chain adjuster but since fitting a pull down chain adjuster it's stopped. I put mine down to the chain running closer to the breather than it was ever intended to.
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CANbus
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blue wrote:I'd imagine if it's a drive side oil seal problem you'll be burning gearbox oil resulting in loads of smoke from your exhaust.
Any idea what size front sprocket you're using?
I use 20 & 21 tooth sprockets and had the same issue using a push up chain adjuster but since fitting a pull down chain adjuster it's stopped. I put mine down to the chain running closer to the breather than it was ever intended to.
yep blue, I think you nailed it, thx. It appears there was to much oil being carried in that area. I knocked up an extension out of a kickstart shaft and its fixed the problem. :)

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