In the past couple of years the quality of       our fuel has changed drastically in       different regions of the US.  It changes       from summer to winter and seems to be       different in Los Angles or Maine compared       to Texas to Alaska.  To keep up with the       Government mandated leaner, oxygenated       fuel we have made 3 increases in jet size       to accommodate the new fuel.        A properly jetted carb, that worked great       a couple of years ago, may have lost some       of its performance due to the new fuels.        There are several symptoms, needing high       idle, hesitation on acceleration, a flat spot       around 2500 rpm, or surge a a certain       RPM.  Any modifications used to increase       performance such as headers, electronic       ignition, free flow exhaust, snorkel will       definitely affect carb performance.  It       comes without saying that a bigger cam,       reworked motor, or a bored motor makes a       difference.  We all know that altitude and       extreme temperature or humidity affects       the air to fuel ratio.  Now, if any of these       factors are combined, there is an extreme       affect when combined with lean fuel.        Weber recognized this and has designed a       kit to have a variety of jets for all circuits       available when tuning your engine.  Our jet       kits come with simple tuning instructions       and a variety of jets to cover the stock       and modified engine.  We have designed       these jet kits from years of experience       jetting carbs on engine all over the       country with all types of modifications.  If       you are experiencing any of these       symptoms from your weber carb or simply       want to improve the quality and       performance from your engine, then you       NEED this kit.  Pick your carb below for the appropriate Jet Pac.