1922 Powerplus drilled holes in barrels

[Baytown]

Can't remember if I asked this before, but my 1922 Powerplus has a very small hole drilled inline with the valve stems for each valve, on both cylinders, between the second and third fins (from the bottom of the fins).
Why would this have been done?
All it does is leak a bit of oil that I can tell.

Thanks for any suggestions.

Ken.

[20scout]

Sorry Baytown, I have asked that question before and never got much of an answer. I'm sure some day, some one will speek up and it will all make sence.
TR

[Baytown]

Thanks for the reply re this issue TR.
Amazes me sometimes that with the knowledge base on this list relevant to old US machines, that the silence can be so deafening!
Have you actually experienced the same thing, and if so, on what type of machines?

Best wishes mate.

Ken.

[AdminGuy]

maybe so that one could manually oil the stems if needed?

[Baytown]

Hi Admin.
Not sure how that would work, as these are about 1/2 mm in diameter if that (sorry, don't know the imperial equivilent).
You would be going to get a hypodermic in there. I tend to think they are breathers, but why? Oil pressure in the valve guides is a good thing!
I'll post a shot on the site ASAP.

Best wishes mate.

Ken.

[20scout]

Hey Baytown,
I had a chance to talk with a few more people about this and this is what we came up with. At Davenport I seen a engine with a very small line going from the crank case to the just front cylinder. Crank case pressure has always been an issue with these old bikes and "perhaps" this was one of Indian's attempts to deal with it. If Indian had put this new idea into production and then changed there minds, they would have to deal with all the new cylinders that had all ready been drilled. Now my guess is that they would not scrap them out but plugged and used them. Or has the line been removed and the line discarted? I have no prof that this was what was done but I would tend to believe this untill someone else comes up with something that makes better sence. Any other ideas???

TR

[swall]

There was a practice of drilling the cylinders near the base to relieve crankcase pressure and reduce the pumping loss and thus get a small hp increase. This was known as "base porting". Perhaps that is the purpose of these holes.

[Baytown]

Hi fellas.
Thanks for the info, but these holes are about 1mm in diameter. The ported bases that I have seen are a lot larger in diameter. The mystery continues.

Best wishes all.

Ken.

[gent]

drillings leading to valve guides

I believe the intention is to push the nozzle of a pressure type oil can up against these holes and pump in some oil occasionally. Replacement guides would have to be drilled after installation. Probably not stock, but I have seen similar modifications to English Sunbeams and racing Peashooter Harleys.