Chasing an illusive oil leak

[cbertozz]

I?ve been chasing the source of this oil for ages. It isn?t a big leak but it comes up the engine and sprays back along the tail fairing.

Have changed all the external case gaskets but no luck.

Any ideas?




p.s I know the engine bracket is missing.

 

[Haggis]

Check for cracks in the head - around the cam chain tunnel. From there, oil can flow into the plug area, and then forward and out to the front of the engine via small cast holes which are between the fins. From there, wind takes it backwards.

 

[Grant]

A little oil goes a long way.
If there is a drip at the stud at the front of the cam tunnel this is probably the culprit.
Could be cracks around the cam tunnel (common) or maybe the gasket has let go, or oil travelling down the thread of that stud.

 

[Lee87H]

I have an oil seepage on the head somewhere,I wouldn't call it a leak yet,if it's the common cracks around the cam tunnel,what is the fix?

 

[gpacs]

The crack at the camchain tunnel can be welded up. We have done several here, put one back together just before going to the Salt Racing. Usually this is on the early heads that have no radius on the corner castings at that point, but have sharp coners that concentrate the stress forces there. I've never seen an RGS head that cracked in that place.

We have found many years ago that simply welding around the camchain tunnel creates stresses in the head and it will often crack again. The key is to remove the bridge in the head completely.

Going off on a tangeant for a moment: This opens up another can of worms discussed elsewhere on the forum as to the correct head tensioning sequence. So often I hear that the factory got it wrong or they thought it was a good idea at the time, but the fact is the factory sequence for tensioning the triple head is correct. It is a sequence that treats the two sides of the camchain tunnel as separate but together i.e. the engine is a twin and a single, and then integrates the two individual requirements of tightening into one sequence.

When the bridge in the camchain tunnel is removed adhering to the factory head sequence is even more important.

Re: the elusive oil leak: it is difficult to see exactly where it is coming from the photos but it looks clean, as apposed to the oil from a worn guide getting past the exhaust flange.

 

[cbertozz]

This sucker does appear to have a disproportionate amount of oil on it - is this the stud referred to?

The point Greg makes about the colour of the oil - yes absolutely it?s clean oil coming out that then gets dirty later from road grime but when at first it starts to leak it?s clean.

 

[gpacs]

The crack at the camchain tunnel can be welded up.

pic attached.
This is a proven method that has been around for 20+ years. Not removing the bridge has been known to cause problems again later on.

 

[Grant]

This sucker does appear to have a disproportionate amount of oil on it - is this the stud referred to?

Not the one I was referring to anyway.
I mentioned the stud at the front of the engine at the cam tunnel. The one you show is on the left side in front of the primary chain casing.

Look between downpipes 2 and 3 and you will find a nut where the stud passes through the head an cylinders at the cam tunnel.