Honda305.com Forum

Go with the stock and tried & true split collar, I would think. Not familiar with the one piece collar. The split collar is suited to conform with header contours / curves and is what Honda used successfully Not familiar with the different muffler gaskets. Others may be. But, start at the header-to ...

Could outside air be entering into the exhaust stream? It can cause banging exhaust. You might check all exhaust joints, clamps and seams.

Here's an older Honda305.com post with good jetting info:
viewtopic.php?t=7636064

These carbs show up on eBay often. Here are two RH carbs:
https://www.ebay.com/itm/175536759744?
https://www.ebay.com/itm/135376001828?

Here's a pair of carburetors for parts:
https://www.ebay.com/itm/356347701725?

... OR, am I just to move the lever counter clockwise enough from 'rest' to install at the 11o'clock position? Try it this way first, which should provide enough spring tension. You'll have to trial-and-error fit alignment with the splines; one spline either way can make a big difference in final r...

Lowering needles will lean the mixture. Raising needles will provide a richer mixture. Engine might be starving for fuel at higher RPM, so raising needles could provide a clue.

Start with middle notch on the needles. Also, the carb jets degrade with time and wear. Consider replacing them if not already. This forum has a good search capability. Did a search for "needle" and found: https://www.honda305.com/forums/search.php?st=0&sk=t&sd=d&sr=posts&keywords=needle&fid%5B%5D=1...