I seems I cant leave things alone, A few days the cold and now the rain sent me back to the workshop with the Comet. I was not happy with the ignition timing for the starting so I retimed it at the 4deg closed ATD ran it on the bench (electric start) all Ok. Then I absentmindedly wiped the offending (rear) pushrod tube and seal of all oil and left it. I did it again on the following day and suddenly thought "I am sure I did that yesterday! This time I spent some time with rag and petrol and it was really oil free when I left it, and guess what? this morning its oily again all around the seal at the bottom of the tube and the engine has not run...With regard to the bottom tube seal I am beginning to think that the real culprit is not the pushrod tubes or the standard seals (and I have tried new tubes and all the options from O rings to special seals) or what glue you add to the assembly the fact that all my engines are oil tight there except one(and its not a 'D') is leading me to think the fault lies in the shape of the crankcase recess even given I cant see it. anyway as I said on another thread, sod it it can weep this season I am riding.
You can pull the sprocket holder off the Alton shaft then trim the shoulder back .09" if you have a Lathe. Then move the Alton in more.It appears to me the only ability to adjust the gap on an Alton install,
shown above as 0.090", would be the ability to move the pre installed shaft hub.
This Alton shaft hub does not appear to be movable.
So the "gap" is fixed gap for each Vincent twin install.
View attachment 41724
So this 0.090" gap must be pretty standard fare for Vincent twin.