Over oiling

So, has the primary issue of "over oiling" issue been resolved yet (oil pooling in rocker cavities) or have we stuck the head in the sand and pretended its not happening.... Of course its going to get excessive oil into the combustion chamber via the valve guides if its pooling with a bit of sump pressure...
then blow whatever color you can think of... .. gotta start at the beginning!!

Regarding the over oiling

I have removed the inspection cover and poored oil in, it does drain in less than a min when I have filled it up quiet full, but I still think there is too much oil being pumped up there, obviously when the engine gets hotter the oil will drain quicker and the pressure feeding the top will drop slightly.

I have also removed the head again (I can do this in my sleep now) the exhaust side looks a bit black but dry, the inlet on the right hand side was slightly wet looking and also there was som score marks on the valve near the top, may be there was a rough bit in the guide, anyway that valve is now scrap so we start again.

Mike,
I run 60 to 80 lbs of oil pressure on my bike with a custom oil pump. I have no restriction in the line to the head. If the flat on the rocker spindle is facing outward and the spindle to rocker clearance is reasonable it would be difficult to flood the head with oil.

Leakage between the guide and head is a common problem particularly if you are using cast iron guides. The guide hole must be free of scores and sealant is advised when the guide is installed.

If you want to send the head to me I can dye test it for leakage or pores. It is not an expensive project and might point you in the right direction. Jim

bigmike76 said:

Regarding the over oiling

I have removed the inspection cover and poored oil in, it does drain in less than a min when I have filled it up quiet full, but I still think there is too much oil being pumped up there, obviously when the engine gets hotter the oil will drain quicker and the pressure feeding the top will drop slightly.

I have also removed the head again (I can do this in my sleep now) the exhaust side looks a bit black but dry, the inlet on the right hand side was slightly wet looking and also there was som score marks on the valve near the top, may be there was a rough bit in the guide, anyway that valve is now scrap so we start again.

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Just as a mention, when I obtained my 73 850 Cmdo the PO disclosed that the left side did smoke. I imagine in my case from the photo attached, looking through the exhaust manifold you can see an oil leak via the guide.

[ATTACH=full]54372[/ATTACH]

While the head is off the barrels.... fill the rocker cavities seperately and observe their "draining".. I would have thought a 1/2 cup of oil would drain quicker than a "Less than a min"... Maybe be a fellow forum member who has a head off can do the same experiment... and also do a "flow/drain test" on the barrel to sump passages..

Im Back to the same theory where "if the oil pools into the rocker cavity, due to poor drainage then it will of course find any escape route possible including the valve guide or guides" which as you know will cause a smoking effect....

Ugh what an annoying drag just reading about it. Do note only the intake guides see low chamber pressure to draw oil in, so the ones that get seals, unless there is some very serious issues with the exhaust seats sealing. You can't really do a valid drain down test with the head off as the main restrictions can be the barrel drain area and the lifter front bevels. You can check if intake rocker drains out as expected with head on bench. Comnoz may be last resort to solve or find its trash.

Had this smoking issue with a 650 ss, After conversion to a pressure feed the bike smoked, i fitted valve stem seals ..made no differance!
What i found was the guide was to high, the seal lip on full open "dropped" into the valve collet taper,allowing a gap to appear ,this drew in oil and then the when the seal moved to the valves full dia it PUMPED in the oil.


I cut down the guide hight [moving the seal down] and this cured the smoking, at the same time i replaced the "floppy" seals with 7mm ford type which have garter springs around the top edge.
Some Norton after market seals are sloppy fitting.

Ugh, as Hobot says "what n annoying drag"... I cant believe this is not resolved yet

i tried to copy n paste 750 "service notes" couldnt do it .. Basically is said that "if the rocker spindles when 180 degrees out you will get pooling in the rocker cavity"...

I hope somebody has these notes and can paste them that section..

toppy said:

Are you sure you have the correct type of rocker spindles an they are all fitted correctly ?

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The third reply was me so what's the end to this one Big Mike???

toppy said:

Are you sure you have the correct type of rocker spindles an they are all fitted correctly ?

Click to expand...

I said that as the third reply so what's the end to this one Big Mike ????

rocker spindles fitted with flats facing out and no wear on rockers

Oil found to be passing down the side of valve guides on exhaust and inlet, even though thay were brand new.

After reading some other threads it is a common issue don't know why I have never noticed it before.

Fingers crossed when this has been sorted out for me I will have no more problems.

And it would seem that pooring liquid into the heads to check valve seating isn't a great way of doing it, as they didn't leak anything overnight, but after a vacume check today it reveals both inlet were letting air passed.

Lesson is if its having work done, do the lot and have it checked by someone with all the correct equipment.

Now there is just one more thing which will probably be answered straight away.

The single carb manifold, which way up should it be mounted, one way and the carb sits straighter to the head and the other way it tilts slightly more at an angle, but only slightly different to each other?

The leveler the carb the better plus gives more clearance for cables entering the top and stuffing on after market small-ish so so filtering while flow restricting afterthought cutie pie air filters. Intake guides are the ones that would cause smoking in chamber as they see the low chamber pressure as intake opens and head tilt allows oil to pile up inside intake rock away from the single RH drain passage way, way more than exhaust side which piles up oil over the push rod/lifter drains. Valve guides seals should only be needed on intake side as exht. side should never see low chamber pressure only the hi pressure blast out as valve lifts. Nothing for it but slap back on and see if smokes and if still does then start from scratch testing for cracks and clearances or seek another head in mean time.