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Navigator Breather

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Navigator Breather

Posted by steven_tyrer at November 13. 2018

On the back of my Navigator engine near the chain sprocket, there is a hole that I think is a crankcase breather, there was a 3/8 brass bolt with a hole up its centre ramed in the hole. Can someone confirm what should fit in this hole. I have the equipment to make the part just need to know what it looks like (cannot find anything in the part list)

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Re: Navigator Breather

Posted by dan_field at November 13. 2018

Hi Steven, Yes it’s the crankcase breather. There’s a few threads on this, have a go with the search facility. There’s one  here: https://www.nortonownersclub.org/noc-chat/technical3-light-twins-forum/319906982

Mine has a short length of copper pipe pressed into the hole, which I think is original, there doesn’t appear to be any threaded nipple or similar to hold it in as there is on the earlier engines. There’s a pic of mine in the thread link I’ve copied above.

As a short fix I expect jbweld would hold the copper pipe in there

dan

 

Re: Navigator Breather

Posted by nicholas_clarke at November 13. 2018

Hi Steven, on my original late 1964 Navigator the crank case breather is just a length of metal pipe a couple of inches long fitting into that hole - I've never removed it so I don't know if it is threaded in or a shrink fit.   A rubber pipe fits on to it and leads up to the front of two short metal pipes let in to the top inside face of the oil tank.  The second pipe is for a rubber pipe which leads down to a hole at the front of the chain guard and acts as a chain lubricator.   The earlier Navigator and Jubilee had a similar oil breather pipe in the same place but if my memory serves me right it was held in by a screw in collar.   Sadly I don't have a picture and I couldn't find one on the internet - perhaps someone else can help.

Regards

Nick

Re: Navigator Breather

Posted by nicholas_clarke at November 13. 2018

Hi again Steve, Dan's picture shows a pipe rather different from mine which is much shorter and comes straight out of the crankcase and only projects about 2" past the casting above the final drive sprocket.   It appears to be shrunk in. I was right about the earlier engines, they had a metal pipe held in by a screw in collar.  These are available from the NOC shop - I have attached the pictures from the shop page to give you an idea of what it looks like.

Nick

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Re: Navigator Breather

Posted by dan_field at November 13. 2018

The pipe on the earlier engines were in a different place, just above the gearbox sprocket and hidden between the cases, it was a pita to get at, and prone to chain damage. My guess is that they were pressed in when the cases were hot, but you could solder or glue.

Dan

Re: Navigator Breather

Posted by steven_tyrer at November 13. 2018

Previously Dan Field wrote:

Hi Steven, Yes it’s the crankcase breather. There’s a few threads on this, have a go with the search facility. There’s one  here: https://www.nortonownersclub.org/noc-chat/technical3-light-twins-forum/319906982

Mine has a short length of copper pipe pressed into the hole, which I think is original, there doesn’t appear to be any threaded nipple or similar to hold it in as there is on the earlier engines. There’s a pic of mine in the thread link I’ve copied above.

As a short fix I expect jbweld would hold the copper pipe in there

dan

Thaks Dan that make sence and thanks for the link.

Steve

 

Re: Navigator Breather

Posted by steven_tyrer at November 13. 2018

Previously Nick Clarke wrote:

Hi again Steve, Dan's picture shows a pipe rather different from mine which is much shorter and comes straight out of the crankcase and only projects about 2" past the casting above the final drive sprocket.   It appears to be shrunk in. I was right about the earlier engines, they had a metal pipe held in by a screw in collar.  These are available from the NOC shop - I have attached the pictures from the shop page to give you an idea of what it looks like.

Nick

Thanks, Nick for your help and now I know what to do :)

Steve

Re: Navigator Breather

Posted by steven_tyrer at November 13. 2018

Previously Dan Field wrote:

The pipe on the earlier engines were in a different place, just above the gearbox sprocket and hidden between the cases, it was a pita to get at, and prone to chain damage. My guess is that they were pressed in when the cases were hot, but you could solder or glue.

Dan

Great information Dan again thanks for your help.

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