If you actually get a higher ampere motor on the old cast iron machines they will punch through the fabric with greater strength. However, the YDK motors, and at least one other brand I have used haven't been stronger, even thought the specs given inditaced it was three times as strong. I don't know the explanation for this, specs aren't everyting at least. It was speedier though. I cleaned and regreased the old motor in stead, it looked better on the machine than a white one
I think your 201 with original motor setup should be up to bamboo bump and cotton drill, as long as it goes under the foot with out problem it should do it with ease. I would assume something needs sorting out if it doesn't. Has it been a long time since the needle plate and bobbin case have been out? Is the belt slipping? It might need to be wiped off along with the groove in the hand wheel and pulley, maybe replaced if it's old. It does need oiling now and then, and the two round covers under the machine, particularly under the bobbin case can sometimes hide a few sins, but they tend to be clean, at most just a bit dry.
My 201 struggles a bit with flat felled seams, especially where four pieces of fabric joins, but it's more of a bump issue,, a stronger motor will not help, a longer foot will, or an even out tool. It does layers of dense and heavy fabric with ease, even maxed out to what it can accept under the presser foot. Getting my 201 to free motion with nice even stitches is work in itself.