1964 Cylinders

[leversole]

I believe I am the third owner of my 1964 Duo Glide, the machine is unrestored and from everything I know, 99% original. It was a daily rider for my first three years, occasional ride the next 10, then sat for 5 years, I got it back going two years ago for occasional rides (once every week or so....lately, after a couple of hours I would lose one of the cylinders and have to limp home, my camera images show a LOT of carbon build on the combustion chamber and piston top. Oil is coming from somewhere. On this last occurrence, the carbon was built up around the spark [lug hole and I could not get my camera in to see what was going on...(besides a little fresh oil fouling the plugs were usually clean).
Anyway, I took the front head off today thinking it was time for a new top end....I got the front head off and it was not as bad as I thought, as you can see in the photo, the build up was around the spark plug hole...anyway, I tried to measure the cylinder (as best as I could while still on the motor in the frame) and the measurement from front to back in middle and top is only 3.4380 to 3.4381...which only .0005 to .0007 more that stock. I know the clearance is based on the piston size, but should I be shocked that a 61 year old bore is hardly worn?
This brings me to my question, the cylinder's have been painted black, which I know is not original, but it could be they were painted in place?!?, so my question is given the casting marks (I cannot find any as described in Palmers book) shown in the picture, are these the original cylinders? casting mark is 5 - 3...
I don't want to disturb the rings if the oil is coming from the valve guides so I am hesitant to pull the cylinder off to get better measurements...
Thoughts?
Thanks in advance
Leslie

[Rubone]

It is likely they are original since they have no oil feed holes and all previous types up to '62 do have those holes.

[BigLakeBob]

Two years ago my '69 Shovel developed a knock and needed wrist pin bushings. Upon disassembly of the top end that had 53K miles since the last rebuild, I still had cross hatches and the bore measured fine. I ball honed, put in new rings and compression is fine. I don't think it matters about being 61 years old, miles matter. It's all your decision, but being where you're at on disassembly, you could remove the cylinders, paint them, re-hone and install new rings. If you plan on removing the rear head as well, you're almost there. Are your cylinder base gaskets leaking?

[dukekleman]

Leslie,

Bobs statement and questions above are exactly the thoughts I share without repeating him entirely.
I'll echo that you are almost there.

Gasketing maybe the lead contributor to your issues.
The front cylinder head you have removed shows gasketing issues in your photo.
Screenshot_20260105-064529~2.png

Hope this helps,

Duke Kleman

[joe fxs fxr]

And, yes, it's not hard to paint cylinders in place with a brush.

[leversole]

Thanks A, I will continue and get the rear cylinder off and get everything properly measured. If in spec I will put a cross hatch in (didn't know if that would make the bore bigger) and put new rings in. Now on to the heads, which need seats anyhow (although I have been running unleaded for years). Also, yes, the base gaskets were leaking.