My carbs were missing 2 of the main jet retaining leaf springs and the other 2 were withering away from rust. I made 2 new ones from a hacksaw blade, and that worked until one of them broke in half. Frustrated, I devised a new method to hold the main jets in place. Not trying to re-invent the wheel here, but as we all know, those little leaf springs are not available in the aftermarket and only pop up on eBay once in a great while. So here's what I came up with:
I cut a washer on one side, then slipped it on the unused upper main jet groove, and clamped it so it won't come off. This washer provides the place for a coil spring to sit, performing the same function as the factory leaf spring type retainer. So far so good as far as functionality is concerned.