First, it would help if we knew your location. Second, you'll get more answers in the Vegetable forum.

You'll find the best information for your area by asking gardeners from your area (your local ag extension/master gardeners might have a planting calendar, also). But, in my garden I plant pole beans in July for a September crop. I haven't grown yard-longs over pole beans specifically, but I've grown pole beans over near-their-end pea vines before and that works fine (looks messy, though). Are your bean plants dying down right now? If they're still actively growing they might crowd the yard-longs a bit.

I got an answer in the Vegetable Forum thank you. This does appear to be a somewhat slow forum.