I had some difficulty fitting the oil pump on the 1360 motor.
John McDougall fitted dozens of them but still gave me a forewarning " if it goes badly just stop and go watch TV for the rest of the day. Try again the next day"
I nearly had to turn the TV set on.
These were new Molnar cases. The oil pump housing bore looked like a mirror, as did all of the machined surfaces on those cases.
It measured exactly correct for a very slight interference fit when cold.
With cases heated and oil pump sleeve cold, the sleeve went in most of the way quite nicely then jammed hard.
I tried to remove it but by now the heat from the case had gone into the oil pump sleeve. It was a proper gong show getting the sleeve out.
The problem was that the main bearing outer race was protruding about 5 thou into the oil pump bore space in one spot. You likely wouldnt encounter this problem with original cases.
Had I first used David's method or Vincent Speet's method of checking with a reamer or slightly undersized piece of round stock, the problem would have been avoided.
After using a Dremel to remove a tiny bit of material from the main bearing race, I made a 1 thou under piece then used it with some grinding paste to open the bore just a little.
This was after going back to all five Vincent books to reread the bit on fitting the oil pump.
At least one publication ( Richardson?)
recommended a " light push fit when cold"
I removed enough aluminium from the case so that the sleeve would slide about half way in when cold.
When heated, the cold sleeve now went in easily, though still best to work quickly and get the position right asap.
The bike does wet sump pretty quickly and I wonder if this is due to the relatively loose fit made with the sleeve.
I did read that all new Maughans 2 start pumps like to wet sump, so decided to live with it rather than repeat with another new pump and hope for a different outcome.
Instead I made up a manual oil valve that is operated by the ignition key.
The end result is good, I can leave the bike all winter, turn the oil on in the Spring and go. Best of all, no oil on the floor!
Glen