I'm sure this question has been asked before. My 05 I just bought has a problem with gas being puffed back out of the carb. Not sure if the valves are out or its just a carb issue. I can crack the the throttle from an idle when it's warm and it will literally pop and puff gas back out the top of the carb. Not sure what's going on.
Carb troubles
- Thread starter islogrm
- Start date
Help Support VMAX Forum:
A common complaint of new Vmax owners is that when they take possession of a used bike, there is a need to have the carbs serviced. It's not that hard to learn how to do it yourself but it's awfully easier to pay to have someone go through the carbs for you but it is expensive. Take a look for the factory service manual which is available by using the search function in the upper right hand corner. There are also many threads on here about how to clean the carburetors.
Briefly the false gas tank cover needs to be removed, the airbox needs to be removed, and the rack of carburetors has to be removed and the easiest way to disconnect the carburetor control cables is at the Oblong nylon Box about a foot up the cables from where they are hooked to the carburetor rack throttle actuation mechanism. Splitting the carburetor rack into two pairs allows you to easily remove the float bowls and then you can access the jet block which has two brass carburetor jets in it the smaller of the two with the pilot jet is the one that normally gets clogged as it is the smallest orifice in the carburetor passageways. Be sure to use a narrow with slot head screwdriver that fits tightly in the female slot in the brass pilot jet so that you do not break off the brass female end. The best way to clean your carburetors is with an ultrasonic cleaner. Removal of the jet black allows you to access the two brass Jets and to make sure that they are see-through clean. If this is your first time and I assume it is I suggest that you use your camera to take pictures at every step that you're doing and take notes as well.
Briefly the false gas tank cover needs to be removed, the airbox needs to be removed, and the rack of carburetors has to be removed and the easiest way to disconnect the carburetor control cables is at the Oblong nylon Box about a foot up the cables from where they are hooked to the carburetor rack throttle actuation mechanism. Splitting the carburetor rack into two pairs allows you to easily remove the float bowls and then you can access the jet block which has two brass carburetor jets in it the smaller of the two with the pilot jet is the one that normally gets clogged as it is the smallest orifice in the carburetor passageways. Be sure to use a narrow with slot head screwdriver that fits tightly in the female slot in the brass pilot jet so that you do not break off the brass female end. The best way to clean your carburetors is with an ultrasonic cleaner. Removal of the jet black allows you to access the two brass Jets and to make sure that they are see-through clean. If this is your first time and I assume it is I suggest that you use your camera to take pictures at every step that you're doing and take notes as well.
Last edited:
Just done that on 2 consecutive weekends.
The hardest part is getting the carb rubbers off the V boost manifold.
After undoing the screws on the clamps, try pushing a flat bladed screwdriver in between the rubber and manifold to loosen it a bit, you will be able to do 1/4 of the way round.
The try pulling the carbs off, pull on the left side, the right in a rocking motion. You may get lucky but I've never managed it. Otherwise use a piece of wood to lever against the carb rack and the boost manifold.
Once one side pops off, try the pulling/rocking as described above.
You need to split the carbs, the screws holding the 2 pairs together are extremely tight. Use an impact screwdriver to avoid chewing up the screw heads. BTW purchase a set of JIS screwdrivers - these are Japanese equivalent of positive, cross head, phillips type.
One of the carb bottoms is a nightmare to get on and off due to the position of the inlet pipe. Keep turning and twisting the base until you get it off - it's like one of those children's 3D puzzles........ but much harder. Don't be tempted to bend the pipe I've never tried that as it is guaranteed to end in tears.
Also when removing the jets, make sure you use the biggest screwdriver with the thickest blade that you can fit inside the holes in the jet block that fit the slots in the jets else it is easy to ruin the slots int the brass jets..... and then you would need to drill them out with a risk of damaging the jet blocks.
The small rubber bug can be difficult to refit. Put a small amount of petroleum jelly (it dissolves in petrol /gas) and use a small diameter drill, blunt end, to push the plug in - the plug has a blind hole.
The hardest part is getting the carb rubbers off the V boost manifold.
After undoing the screws on the clamps, try pushing a flat bladed screwdriver in between the rubber and manifold to loosen it a bit, you will be able to do 1/4 of the way round.
The try pulling the carbs off, pull on the left side, the right in a rocking motion. You may get lucky but I've never managed it. Otherwise use a piece of wood to lever against the carb rack and the boost manifold.
Once one side pops off, try the pulling/rocking as described above.
You need to split the carbs, the screws holding the 2 pairs together are extremely tight. Use an impact screwdriver to avoid chewing up the screw heads. BTW purchase a set of JIS screwdrivers - these are Japanese equivalent of positive, cross head, phillips type.
One of the carb bottoms is a nightmare to get on and off due to the position of the inlet pipe. Keep turning and twisting the base until you get it off - it's like one of those children's 3D puzzles........ but much harder. Don't be tempted to bend the pipe I've never tried that as it is guaranteed to end in tears.
Also when removing the jets, make sure you use the biggest screwdriver with the thickest blade that you can fit inside the holes in the jet block that fit the slots in the jets else it is easy to ruin the slots int the brass jets..... and then you would need to drill them out with a risk of damaging the jet blocks.
The small rubber bug can be difficult to refit. Put a small amount of petroleum jelly (it dissolves in petrol /gas) and use a small diameter drill, blunt end, to push the plug in - the plug has a blind hole.
