Connect them with a piece of CPVC water pipe. In the US, 1/2 inch CPVC. Other parts of the world 15mm PVC. Copper and PEX should also work, they are the same size. Cut a length of the pipe to 107mm (4-1/4 inches).
Test fit to be sure everything fits your spinning wheel. Then use a little SuperGlue (Cyanoacrylate) to secure the bobbin ends to the pipe.
Helpful Hint: If your Majacraft is using a monofilament (fishing line) for the brake, you may need to replace it with cotton thread. The fishing line causes excessive tension on plastic bobbins.
If you find this project useful, let me know in the comments. Also be sure to check out my other projects.