You do not need a choke with the Mikuni's - pump the accelerator a few times - crank the engine and just so you have done your homework correctly she will fire up! But if you have not done you homework - installed incorrect jets - guessed on how to set up triples you are going to have problems - if you are not willing to do some research and set your triples up correctly, it would be best for you to stay with SU's cause you're going to have problems. Once Mikuni's are set up correct - and you got a correct air fuel reading (not too lean - not too rich) your basically done until your annual fine tuning. Here is the link to my info for my Mikuni set up http://www.classiczcars.com/forums/showthread.php?42045-Wolf-Creek-Racing-Mikuni-40-s