cfm air box tube

lowes ha ?
you must be talking about the adapter ?
the plumbing fittings are called a "fernco" fitting
lowes may have the size you need ?
for the cfm tube, you'll need 2-1/2"
measure the OD. of your carb for the reduced size

here's a better option and what i use, 3 different colors, and any size you could imagine........

Intake Pipe Reducer
 
I run a silicone intakes silicone reducer for all my big carbs.When I bought my first cfm box 4 years ago I bought the adapter for the stock carb and the one for larger carbs through cfm.I eventually ended up buying a silicone intakes reducer for the 34-35mm carbs since it was a much better reducer than the fernco they supplied.That being said they supplied me with a very nice fitting genuine yamaha boot to fit from there box to the stock carb,unlike there larger carb boot.Here is a pic of the yamaha part # if you want to got that route.Yamaha or the silicone intakes reducer will work best.Stay away from those junk fernco fittings.
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