You have a Dellorto SHA carb, size 14.12 (mm) which should be notated on the side. When he said 15.15 he means the size. He upgraded to a Dellorto SHA 15.15 along with the aftermarket MLM brand intake to match the carbs 15mm size.
When you bought this did the carb have the stock round metal screen filter that fits into the carb, with a separate small plastic dome cover? That's what those 2 people are suggesting would fit in this scenario but I'm assuming yours was bare when bought or you would have tried it. The metal mesh stock filter has several layers that you can pry out one by one for more air flow.
You can also thug it out for more air flow and use a ziptie and pantyhose to cover the carb as a "filter". Although with all that air coming in you would need to rejet the carb to a bigger jet to match your air/fuel mix so you don't run lean.
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