I used a BMW car radiator hose to mount PHF 30 mm carbs to intake stubs on a V65. The changed diameter at the end and fit perfectly. I had to buy two and cut the ends off. Back then they were about twenty bucks apiece. I don’t know the part number or what car they were used on so if you can get a parts guy to look for tapered radiator hoses you might find what you need. They told me they wouldn’t last, they were right. After thirty years they got hard, no longer pliable.