The carb bowl drain nut is located on the bottom of the carb.
remove the seat loosen the gas tank bolts turn the gas switch off pull the hose off the carb gently to not spray gas everywhere pull the tank off pour it upside down in a gas safe container unscrew a small screw at the very bottom of the carb and it will drain the gas from the bowl as well
drain your tank and flush with some gas. you should also remove the bowl from the carb. and drain it as well. Then clean out carb. with carb. cleaner. you may need to get a new gasket for the bowl as well.
a mikuni vm30ss came stock on a 1980 Yamaha tt250,as i have one and am looking for parts for one.Alot of the parts for this carb and bike have been discontinued,so they are unavailible through Yamaha and are very hard to find anywhere..
The "dry" setting is 17.5mm +/- 1mm from the base of the carb gasket surface (without gasket) to the center of the float (furthest point from the pivot point of the float). The "wet" setting is 3mm below the gasket base of the float bowl. to accomplish this you fit a hose to the bowl drain and loop the open end to extend above the float bowl/carb surface. Open the drain screw and measure the fluid level from the bottom of the main carb body.
Sounds like the main jet inside the bowl of your carb may be plugged, there is no adjustment on that choke of that bike it is either full open or half open. take the carb off the bike and clean the carb fully outside and remove the bowl and clean the passage ways of the jet or order new one, reattach and try it again.
on the left(shifter side) of the carb, on the float bowl. small standard screw (flat head)
To begin, there is a "nipple" at the bottom of each floatbowl that you can attach a piece of tubing to. There is a drain screw (flathead) on the float bowl nearby that releases the remaining fuel from the bowl when turned about 2 turns. The screw can be accessed from the opposite side of the carb location i.e. drain screw for right side carbs access from the left side of the bike.
water in gas or out of time change the spark plug and check the carb bowl for water if there is then drain the tank and clean the carb Additional comment: Often when you have a motorcycle or ATV that is backfiring you will find that your bike is having a problem with bad spark timing. This will also cause your Jerking... Take your bike to a profession and have them look at the carburetor adjustment and the timing.
Tank no, you can disconnect the reserve fuel line from the fuel off switch,to drain the tank. The carb has a drain in the bottom of the bowl to drain for storage to prevent fuel gum-up.
Remove them with some WD-40 and some vice grips.
sounds like you have a float that is stuck. when the float stcks down it allows more gas into the carb. you may need to pull the carb to clean the float needle and seat.
not receiving enough fuel to bowl on carb