What I have is a 401g and a 411g. These are not the same as a 401a. They were made to be treadled. I have successfully gotten the 401g into a table with treadle. It shreads the belt. I have seen where I could take a file and gouge some metal off the wheel or off the top. Then I went to the sewing machine shop and the repairman says it needs a different fly wheel to run right. The 401g motor is removed already. I'm going to post some pics here and see if it helps. I really should shoot a couple of it in the treadle.
401A on left 401G on right - The 401G has a knock out on the bottom right. The bobbin winder is on the top. The balance wheel is a bit different. Some people take a file and cut a groove on the balance wheel.
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411G on left and 401A on right. Notice the channel inside where a belt can go. It is to the right and below the shaft. Look at the 411G on the right - Can you see more of the balance wheel than you can on the 401A or 404?
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The 401A is on the left. The 411G on the right has a hole in the lower left side of the rear. It is a little rectangle - it is the bottom of the channel for the belt to pass through. The 401A does not have this channel.
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