I am wondering if anyone can point me in a direction to find tuning guides for Mikuni carb's I have Mikuni model TM40-8142's that I have had some trouble with, seems to run akin to being on choke, I am pretty confident in the way the jetting is set-up as I have ran the same jet sizes for a few years and had good luck in the past. Any info would be appreciated.

is this for an older sled?

if  it is, does it have the little vacume fuel pump? buy a gasket kit for that, clean the carb super good, check all the air and fuel lines for cracks, also put a inline fuel filter in there,

old units have lots of dirt wich makes you think you need to tinker and tune the carb, worked in a sled shop years back and all the older sleds and boat motors just needed to be cleaned up,, 9 out of 10 times 

Hey thanks for the suggestion! It seems to be getting tons and tons of fuel and I can't put my fingure on it, my motor was literally completly full of fuel earlier today as well as my pipe. Any idea's there?? And yes it's a 98' chassis 00' 800 motor. Old school I know...

Those carbs have vent lines which are to be vented into the airbox, make sure they are.

pilots #40

Mains 340 stock pipe

needle 2nd slot from top

for stk 700-800

check choke cable tension, I keep mine real loose so I can have it on half chock and just add a bit of fuel when going up a long trail to keep motor cool. clean choke plungers make sure debris hasn't held them up and add fuel.

Ted,

Terra Alps Racing inc.