What is the best carb to use on the Zen 26 over the stock wt644 for over all pref. there are so many out there that say big bore some say the 257 some say the 813. but what i cant fig out is they all have the same main bore of 15.88mm and the vent. bore of 12.77mm. so how can they all say big bore over stock? Sounds like a bunch of sales tactics,so what is the best. RJ

WT-257 .... WT-488 .... WT-644 .... WT-633 .... WT-771 ****** ALL the SAME size across throttles Butterfly & Venturi !!

Internal calibration is however QUITE different between them.

For overall stability running stock or modified, the WT-488 & WT-771 carbs are the top of the heap. The WT-257 are MOST common and the easiest to find/least expensive

There is far more to the issue tho than what we can cover here ???

Scott, ty very much for the answer been lookin at so many of them they all say big bore yet all demin. are the same Ron