Primary chaincase oil level

[Phil C]

Seems a bit odd: the primary chaincase on my 1965 B40F is supposed to have 1/4 pint of oil. I thought I'd change it, so I drained out the old oil, and this morning went to renew it. With the bike on its centre stand, and the level screw removed, I took out the big screw where you would do clutch adjustment, and through that hole poured in just over 1/4 pint, but nothing appeared at the level hole. Put in some more (maybe, say, another sixteenth of a pint) - still nothing at the hole.  Should I keep going until it appears, or stop now? Maybe the bike's not quite level?   Phil.

[AWJDThumper]

If you've put 1/4 pint then there's nothing to worry about. However, are you removing the correct screw that acts as the level screw? If so, it's possible the oil hole to the screw is blocked.

[Phil C]

So I could just prod something in there to clear it?   Phil.

[AWJDThumper]

In principle, it should be possible to poke a suitably bent piece of wire through the roof of the hole for the level screw in the primary cover, assuming the hole is actually there

[Phil C]

Thanks AWJDT, but I'm not sure what you mean by suitably bent, or by roof of the hole.  Is it not just a straight hole?    Phil.

[AWJDThumper]

If memory serves me correctly, there is simply a hole drilled vertically down into the top of the level screw hole inside the primary cover. If the oil level is too high, oil simply seeps down through this vertical hole into the level screw hole to the outside of the cover. Using a wire to try to blindly poke through this hole might be a bit difficult. Short of taking the cover off, I might be tempted to take out the level screw and blow air into the hole from a foot pump or high pressure air gun in the hope of clearing any blockage in the small drain hole. However, there's no guarantee that the drain hole is actually there.