That looks like an M-Star. I'd bet it's around a 1986-87 model. Maico went belly-up in the 1985 timeframe and came back as "M-Star" with a bunch of rebranded maico parts.
I wouldn't make a trike out of yours. You may view it as a weird German bike that will be hard to find parts for, but a collector will pay good money for it.
CURRENT RIDES:
1988 Tri-Z 350 Twin
1985 1/2 Tri-Z
1984 IT490
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