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Jubilee oil leak.

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Jubilee oil leak.

Posted by john_dunn1 at September 02. 2018

Not started the Jubilee yet. Turned the engine over a number of times to get some oil circulating. Already noticed that ive got  a small oil leak at the front between the head and cylinder blocks. Brings back memories. I dont think there is much metal around this area. Has anyone worked out on how to stop these leaks.

Thanks

John.

Re: Jubilee oil leak.

Posted by Dan Field at September 02. 2018

I refaced the heads and used new gaskets, ok for the moment! It leaking from everywhere else mind!

Re: Jubilee oil leak.

Posted by patrick_mullen at September 02. 2018

Hello John,

The Jubilee has a reputation for oil leaks but it definitely should not leak oil from the cylinder head joint on simply kicking over the engine.  Are you sure the head studs have been tightened up properly ?.  Did you fit a new gasket ?There is a concealed stud at the front (and another at the back) of the engine deep down inside the rocker covers,  i.e six head studs for each head.

Surely this joint is just the oil draining down from the rockers to the crankcase and it is only a gravity feed not under pressure.

Patrick

Re: Jubilee oil leak.

Posted by Dan Field at September 02. 2018

Oil can sometimes leak from the rocker caps and drip down to look like the head is leaking, the caps can become distorted by over tightening. Easily solved with wet and dry and a piece of glass.

Dan

Re: Jubilee oil leak.

Posted by bryon_currington at September 03. 2018

Previously john_dunn1 wrote:

Not started the Jubilee yet. Turned the engine over a number of times to get some oil circulating. Already noticed that ive got  a small oil leak at the front between the head and cylinder blocks. Brings back memories. I dont think there is much metal around this area. Has anyone worked out on how to stop these leaks.

Thanks

John.

I have almost got mine oil tight except for a few drips from the oil filter cover area the last one was a fine crack in the gearbox casing. At the start after a lot of guessing where the oil was coming from I took off the seat and put the tank sideways in its place and connected it to the carb. This gives a clear view of the top of the engine and after a thorough clean of all the oil you can start up and watch for leaks. The rocker covers are a common one mine was also leaking from the rocker feed T junction hard to see with the tank on. Bryon

Re: Jubilee oil leak.

Posted by dennis_thompson at September 14. 2018

I only started my Jubilee last week after a complete re-build and now I have taken the engine apart again because it was leaking oil so badly.

I waited for a new gasket set from the NOC shop which arrived today and it included the crankcase gasket. However, that gasket fits so badly, particularly around the gearbox, that I have decided to do without one and use gasket sealant only (Loctite 5699). I have reassembled the crankcase and there is no pinching of the main bearing so I am happy with that.

It is a shame that the gasket is such a poor fit. It does not even touch the gearbox casing at the lower rear side when the gasket is secured on the dowels. I think that may have been part of the problem last time though I did not buy the previous gasket set from NOC.

I may dispense with other paper gaskets on the rebuild as they are so thin. I know this may make stripping the engine difficult in future but I would prefer to have an oil-tight set up.

On another note, I was surprised at how much oil was in the crankcase when I took off the sump plate. I know there is a problem with wet sumping but my oil pump has been refurbished so by pass should be low.

I bought an oil tap from Feked but is far too big to fit in the oil lines. I have now bought a mini-gas valve (10mm) that might fit so I will try that. I know there is a real danger of forgetting to turn the oil tap on but my bike may sit for months without being run so wet sumping may be a constant problem.

Dennis

Re: Jubilee oil leak.

Posted by Dan Field at September 14. 2018

I don’t think Jubilees are known for wet slumping, I don’t think  a tap should really be necessary?!

Re: Jubilee oil leak.

Posted by andrew_wibmer at September 14. 2018

Previously dennis_thompson wrote:

I only started my Jubilee last week after a complete re-build and now I have taken the engine apart again because it was leaking oil so badly.

I waited for a new gasket set from the NOC shop which arrived today and it included the crankcase gasket. However, that gasket fits so badly, particularly around the gearbox, that I have decided to do without one and use gasket sealant only (Loctite 5699). I have reassembled the crankcase and there is no pinching of the main bearing so I am happy with that.

It is a shame that the gasket is such a poor fit. It does not even touch the gearbox casing at the lower rear side when the gasket is secured on the dowels. I think that may have been part of the problem last time though I did not buy the previous gasket set from NOC.

I may dispense with other paper gaskets on the rebuild as they are so thin. I know this may make stripping the engine difficult in future but I would prefer to have an oil-tight set up.

On another note, I was surprised at how much oil was in the crankcase when I took off the sump plate. I know there is a problem with wet sumping but my oil pump has been refurbished so by pass should be low.

I bought an oil tap from Feked but is far too big to fit in the oil lines. I have now bought a mini-gas valve (10mm) that might fit so I will try that. I know there is a real danger of forgetting to turn the oil tap on but my bike may sit for months without being run so wet sumping may be a constant problem.

Dennis

 

It might be worth having a look at your oil pump, a search on this site will tell you what to do, but it is worth having a llok to see how much wear there is in the brass face plate. Re the gaskets, I have used a thread and wellseal, but only after I had faced the surfaces on a plate glass with emery paper, have a look for an excelent article called "Forums and Leaky Lightweights" in Roadholder 290 December 2011, excelent article.

 

Andrew

Re: Jubilee oil leak.

Posted by dennis_thompson at September 15. 2018

Thanks both.

The pump was professionally overhauled and there is no wear or gap on the side plates. I can retrofit the tap if I do get a problem with wet sumping so for now I'll just take care with the reassembly and see what happens.

Regards,

Dennis

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