Setting Carb (Main Jet) , 77 SST 440 Yamaha Engine

[DicemanSST]

my first post...I have a 77 Sno Jet Kawasaki that has a vm 36 Mikuni carb  ( well I think it is because thats what is stock on it ).....I have read that the carbs jets are fixed but this carb does have a main jet setting( big white screw ) at the bottom of the carb on the side of the bowl and has a small hose running from the bowl to the top side of the body...you are only able to turn the screw one turn and of course turning it out makes it richer......couple things..was this a stock carb on this sled or do you think someone changed it?...a local shop guy told me that many of the Mikuni Carbs have the main jet screw...is there any proper setting for this or atleast a general idea?...secondly this sled has a cdi and no points right?..Cheers DicemanSST

[DicemanSST]

anybody??

[Trucker]

I have to assume by the sst in your username that is what you have for a sled so yes that is the stock carb and yes it has cdi. The astros had a mix of yamaha and kawasaki engines so things would be different.
I do not know those sleds well and adjustment would depend on temp and elevation just like any other.

[Invader440]

Yes, after looking at the parts book that is the correct carb for the 440 SST and it is a 36mm carb.  Turn bottom screw so tab is pointing straight down.  Air screw adjusted to anywhere from 1/2 - 2 turns from seated that gives you the best idle (I'd say 1 turn would be a good starting point).  Idle screw anywhere from 3-6 turns out from coil bound to give you an idle speed of 2000 rpm.  That's from the service manual.

[DicemanSST]

Yes, after looking at the parts book that is the correct carb for the 440 SST and it is a 36mm carb.  Turn bottom screw so tab is pointing straight down.  Air screw adjusted to anywhere from 1/2 - 2 turns from seated that gives you the best idle (I'd say 1 turn would be a good starting point).  Idle screw anywhere from 3-6 turns out from coil bound to give you an idle speed of 2000 rpm.  That's from the service manual.

Thanks for reply guys....reason I was not sure if it was the right carb was when I look at this website under models I saw the specs for the  77 sno jet 440 stt with the yamaha engine, it said that it was a fixed carb so since  the carb I have can be adjusted ( main jet) I thought maybe it was switched....  secondly should the setting be set  richer when cold and leaner when its warmer out?...was running sled lets say -2 c and srew was about 1/3 turn out and plugs were kinda black, dark....also when I open it up it flies until about 45 to 50 mph then kinda stops,like no more throttle... almost like not enough fuel, or to much fuel and bogging, not sure which one..lol....any thoughts would be great....