I no longer have the Ninja .21 and Ninja .28 engines....But when I ran the .21 motor these were my settings:

I run 30% Maxy's fuel, Ninja #6 plug (#5 plug in cooler weather), stock 7mm venturi, MSR1005 pipe & header and added one thin copper shim (0.004") to increase the deck height. LSN = 5.5 turns out, HSN = 4 turns out. When looking at the needles both are at the 1 o'clock position. Motor never ran over 250* once broke in. During breakin the motor ran at 280-290*.

I still have a 5-pack of Ninja #5 plugs. If anyone is interested email me at [email protected]

Best regards,