Internal Velocity Stacks for Pod Filters

thingiverse

These are velocity stacks I designed to fit INSIDE pod filters. They provide the size and aesthetic of the pods, but dramatically improve the performance of CV type carburetors. CV carbs operate based on the velocity of the incoming airflow, therefore the inlet geometry is extremely influential. Even with correct jetting, they may not work properly if the incoming air is not smooth and laminar. These stacks are designed to channel the airfow into the carburetor/s like the stock intake boots, so that the slides open much sooner and more fully, allowing fuel to be delivered correctly. These will also work on flat-slide type carburetors, but the difference will be less noticeable. These velocity stacks are dimensioned for 52mm pod filters, specifically these (see link), but they should fit others. You could also scale them for different sizes. https://www.ebay.com/itm/382263473114 The stacks simply butt up to the carburetor intake and are held on by the filter. Make sure to rotate the relief cut on the inside upward. You may need to trim some of the rubber on the filter if they don't push inside fully. You should sand the inside of the velocity stacks smooth for best performance. Also feel free to try shrinking or stretching them to experiment with different inlet lengths. Out of the common 3D printing materials, PETG is the most gasoline resistant. I HIGHLY recommend you try these if you are having fuel tuning issues with your CV carburetors. This simple addition easily doubled the power of my motorcycle with pod filters.