Hey every buddy I got a 2003 raptor 660 with 686 big bore kit with cam and jetted turning the plugs black like no tomorrow and once shut off it’s a pig to get going on less I leave it for a bit any advice on what I should do to it I just bought the bike it’s crazy fast but want it to be more reliable
it is over jetted. 99 % of the people out doing this sort of mod think bigger jug you need bigger jets. in most machines that get a big bore factory pilot is ok and you will need to drop one size in the main. if you need the science behind it i did a write up in the yfz sections on jetting big bores. with a 660 you have double the trouble and one of the worst carb set ups i l have ever worked with. the left carb is primarily for the pilot and the right is more for the main but both carbs fuel both circuits. the other issue is they are almost always assembled backwards. when you work on them they are upside down and it gets confusing. do yourself a favor and get the clymer manual and follow the instructions. i have done dozens of carbs and these are the hardest to tune i have ever come across
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