Kymco agility 2012,i want to put a 72cc big bore kit on it,at mo running standard 50cc carb,was told i need to up my jet size.

Check all the bolts, you lost compression.

clean ur carbs they have ever so tiny holes in ur jets and it dont take much to get them clogged if it sat over winter and u did not start once a week or put anything in ur gas to stable it ur gas will turn to slug and clog them also check air fuilter

Same with mine nothing works have you found a solution yet ?

I believe the standard starting place is to go 2 jet sizes bigger, but I would check with the manufacturer of the big bore kit to make sure. Hope this helps

general rule of thumb is to go up about 10 jet sizes,unfortunately it is a bit of trial and error,and you may have to swap out diferrent sizes to get the bike running right,(jets are quite cheap though)but first step about 10 sizes from standard,your local dealer should be able to tell you what jets are in it and supply replacements,if you change to a hgh flow aftermarket air filter you may have to change jet sizes again as changing the filter may effect the mixture ratio in the carbs,,hope this helps