You can futz with the spindle and the chainrings, but usually some wheel redishing is required, especially on a 126 that fits a 7 speed.

...or get truly ghetto fabulous if it's just a beater, and take off the rear D, shorten the chain, and just run it on whatever gear combo gives you good chainline and gearing. The nice part is if the chainline is a little off and it drops the chain in the back, it just upshifts rather than totally throwing it. Craptacular, but why put money into a beater?