Ok thanks Jiem, I wasnt sure if that was a hole or a pen-mark.
So what you are saying is that the throttle response was better once you increased the size of those holes? I noticed in your video, that when you chop the throttle at 1m30s, it takes a while to settle into an idle again. I assume this is a 'feature' of the negative crankcase pressure design. Obvioulsy that fuel/air mixture has more distance to travel, and changes would be a little 'luggish' I assume it is the same for revving up and down. Immediate throttle response is not something that is really 'required' on an engine like this, its not a 3D type engine, but it useful when setting the needles. Any 'stalling' during transition indicates lean settings. Its not going to be as apparent in this environment, and tuning the engine could be a little trickier than normal. At least, thats MY assumption, a logical assumption, not one from experience, so I may be wrong. Have a look at my video on post 1888, the last video of the engine running, you can see that the throttle response on that engine, is very crisp. (BTW, the engine in that video is not the one thats broken its cylinder, its a different one).
Would you mind sharing some details of where your needles are set at the moment?
You say you are running the oil ratio at 25:1, and I see morris runs his at 30:1, do you think there is any danger running at 30:1? I have seen the carbon build up on my busted engine, and I dont like it, would prefer to have lower carbon and hope that a leaner ratio might reduce that.
P.S. 8 Deg C is useful.....where I am, the ambient temp in the summer is in the low to mid 40's....ALL.THE.TIME.....cooling is a bigger challenge here...
Thanks for all your input.