'81 KZ750 LTD & Dynojet Kit

To begin, I am acutely aware that some members here absolutely hate the Dynojet kits. However, I bought a kit on the advice of a friend who has probably owned and repaired more motorcycles than I have teeth (And I still have my wisdom teeth ) Please note that I am already aware of your objections, and that they do not need to be expressed in this thread. You can bet your sweet ass I'm not trashing any parts, and you can enjoy my humblest of apologies if this goes south.

Moving on. It appears I will be installing the kit sooner than later now, and I was wondering if I should install the stage 1 or stage 3. My KZ has an unbaffled Mac 4-1 header on it and the stock airbox with a K&N filter, so it is unclear to me which should be installed.

As it stands, the bike is definitely running lean. It is a hard start, cackles on deceleration, and pops back through the carbs at idle until warm. Oh, and the stumble. It stumbles on hard acceleration and then takes off like a good girl should.

Any kind advices for this poor soul who is probably way over his head?