Oily problems 650SS

Hello as a 650 owner I feel your pain   well like with every problem you need to start with illumination of what you have done so far  and go back over it all methodically    and make sure all mating surfaces   are true and flat  and consider using a copper head gasket and well aniled  and drenched  in blacksmiths oil   and use high melting point grease smreded on both side with a small brush then bolt down from outside in but bolt down in stages starting with 10lb and then next stage and as for the timing cover revconuter drive  the oil seal will of dried out  and my need replacing and oil maybe sucked in passed the head gasket and then then burnt giving you blue smoke. So in any event you have some checking out to do  now all the best  yours Anna j 

Hi David,

May I ask if you have retorqued the head down after it has gone through a few hot/cold cycles? If no, I would do this first. This is only to address the leak issue. I had many sealing issues with a copper gasket, to the point that I binned it.

In my experience, oil rarely gets sucked into the combustion chamber via head gaskets for long - If oil can get in, then combustion gas can and will get out and you will very quickly lose compression with a burnt out gasket, so I doubt if that is your smoke cause.

On my bike (a 67-ish 650 mongrel) I had (foolishly?) "upgraded" to the plain spindle/pressure fed rocker oil feed system (my bike had 3 start oil pump and was fitted with scrolled rocker shafts when I got it) and had a lot of issues with the top end over oiling and smoking badly at idle. (too much oil upstairs = gets sucked down the inlet guides = smoke)

For my bike, a "made specially for me" Reinz composite gasket (trade contacts...) stopped the head leaks, while reverting back to the original scrolled rockers and low pressure feed has cured the idle smoke. Are your rockers or shafts now too worn to limit the oil going to the top? 

It may be worth disconnecting the rocker oil feed at the rear of the timing case and blanking off the supply (a nut instead of the banjo on the bolt usually works to keep it oil tight) and running it - if no more smoke at idle, then there is too much oil going up there. It won't hurt the engine to run without oil feeding the head for a few minutes. If the smoke has now gone, then it is either all new rockers and shafts required (£££), or restrict the oil supply to the head. The top end really doesn't need a ton of oil going to it, so I know what route I would go. A look to the technical section may give you some ideas.

Regarding the timing case  leaks, Anna may well be right as to the timing cover seal no longer sealing on the crank and thus flooding the timing cover giving you the leaky rev counter drive - how long is it since it was last run?

Oil pressure wise, as long as the piston is free to slide in its bore and the spring is ok, there shouldn't be any issues with it. As far as I know, the piston should move a small amount when pre-assembled. The 'slack' should be a few thou rather than tens of thou, and that is what you adjust with shims. I am happy to be corrected on this by those more knowledgable on the matter. In reality, only an oil pressure gauge will give you the true answer as to the setting. Mick Hemmings says the pressure valve assembly should have "a light rattle" - make of that what you will.

Good luck, I hope you get to the bottom of the issue.

Regards,

George.

Our Atlas which has the same system was smoky . Now seems cured with some new rings ,a pair of Commando inlet valves guides and inlet valve seals.  Yours may only need the valve guides and seals.

Anna,

Just two threads earlier under ‘Head tightening’ you advise to tighten the head bolts from ‘the inside out’, now you advise ‘from the outside in’, could you please clarify before someone ‘warps’ their cylinder head.

Regards

Dick

Its OK Richard  I already  have a warped sense of humour ,Beam me up Scotty !!.  

hello well the answers to this is to make sure your engine is on tdc and all valves closed and no weight on the head from the push rods and camshaft  when in the procedure of tightening down the cylinder head   then there is no chance of warping the cylinder head is there now  Yours  Anna J

hello   this oil leak must be down to the oil fairies cleaning or gravity  as oil settles it finds anywhere to run even though the smallest of cracks or joints I use waterproof grease for the timing cover joints and for the taco drive as well and to make a nice oil seal on the primary   chain case   ,now the reason   you maybe  getting oil down the inlet valve stems is the build up  of oil there not getting way and then fining its way down the valve steam  now this could be the oil ways bloced in ether the cylinder head or in the crankcase   were the 90 degrees elbow is witch get blocked with  gasket gue  after an engine rebuild    I use pipe cleaners to unbloc this oil drain way  witch is  built inthe the back of the cylinder head and cylinder barrel  and some times get blocked where the gasket meets both head and barrel  and get blocked up with gasket sealer   My Norton Manxman 650 was fitted with a oil banjo on the inlet cover mounting  so the engine can breath and any acess oil get blown out down a pipe and into the oil tank or a pipe to the chain guard  and part numbers for this are availble  now do keep your selfs safe   yours  anna j 

Hi David.......there have been lots of good suggestions in this thread but I have a feeling that the root causes of your dripping engine may be due to other issues. There appears to be a mix of oily issues mentioned and various moves that you have made to sort them out. However there is no mention of the oil pump being checked and serviced.

The six speed version is notorious for wearing out it scavenge side fairly quickly due to the rubbish it has to swallow when running. These double speed pumps are generally good for only around 50,000 miles if no cartridge filter is fitted in the system. 

The pump then begins to fail to clear the sump of excess oil which looks for other places to head for. So as the pistons descend the sump oil is forced into the timing cover, up the rear drain hole in the barrel to the cylinder head and some also past the pistons and cam followers. The breather system is  overwhelmed and the unwanted oil stain problem gets worse.

The neat oil and vapour that heads into the timing cover then tries to escape via the Rev counter gearbox (if fitted) and also through the magneto or distributor end. Plus any weak gasket areas. At the rear end of the engine the barrel drain hole turns into a pressurized feed hole which begins to fill the inlet rocker area. At the same time the only part of the head gasket that has no eyelet protection (solid copper excepted), unlike the pushrod tunnels, gets a direct feed of oil through the gasket middle straight to the right rear headbolt and gasket edge. See diagram.

Try a refurbishment of your oil pump.  It may help. If you have done this already check the piston rings.