Fergy PM'ed me to suggest making the instructions to correct and prevent POOGS a 'sticky' (Admin function). I think that it is a great idea. Thanks Fergy! So, here are the instructions to correct and prevent POOGS on '85-'06, non-CA models only. If someone has the instructions for CA models, please add them or PM me and I will add them to this post.
Phantom Out Of Gas Syndrome (POOGS)
Motorcycle stalls repeatedly as the fuel level in the gas tank falls below 1/2 full. Symptoms similar to running out of gas. Switching to Reserve has no effect.
Failed gas tank venting system; clogged gas cap vent and/or gas tank vent tube or a failed check valves within the gas cap vent assembly. This prevents air from entering the gas tank to displace fuel being used by the carburetors, resulting in negative gas tank pressure (or vacuum). Negative gas tank pressure prevents fuel from reaching the carburetors causing the motorcycle to stall.
- Fuel level at 1/2 tank of gas or less.
- Ride for a few miles.
- Motorcycle stalls as if out of gas.
- Pull over in a safe location.
- Open gas cap for 3-5 minutes. This relieves the negative gas tank pressure momentarily.
- Close gas cap
- With a few extra cranks the motorcycle starts like there is no problem
- Go to step #2 and symptoms repeat
: Clean gas cap venting system and verify that the gas cap vent assembly check valves are functioning properly. Optional:
The gas tank vent tube (’88 – ’06, non-CA models only) exits in front of the rear tire and may be rubbing against the spinning rear tire, resulting in a clog that resembles black carbon. Relocate the gas vent tube exit, if this is determined to be the debris source.
Gas Tank Venting System Cleaning Instructions:
The process looks complicated, but it only takes about 15 minutes. NOTE:
Instructions below are for ’85 – ’06, non-CA models only. Adjust accordingly for CA (vapor recovery system) models.
Step I: Clean the gas tank vent tube/exit.
For '85-'87 Models with no gas tank vent tube (click on Attachment 3602 for more information):
- These models vent through a small port in the base of the gas cap. The port exit is located in the rear of the gas cap (see attachment above for details.)
- Open the gas cap.
- Locate the gas tank vent port entrance; a small hole located on the gas tank directly in front of the opened gas cap hinge.
- Spray carburetor cleaner or non-chlorinated brake cleaner, using the straw attachment, directly into the gas tank port entrance. The cleaner should exit the rear of the gas cap freely. Have a rag handy to prevent cleaner from running down the sides of the gas tank.
- Use a pipe cleaner or small plastic zip tie to unblock a clogged port, if necessary.
For '88-'06 Models with gas tank vent tube:
Step II: Clean the gas cap vent assembly.
- Place a piece of paper in front of the gas tank vent tube exit. The default (OEM) location is directly in front of the rear tire.
- Open the gas cap.
- Locate the gas tank vent tube entrance; a small hole located on the gas tank directly in front of the opened gas cap hinge.
- Spray carburetor cleaner or non-chlorinated brake cleaner, using the straw attachment, directly into the gas tank vent tube entrance until drips are observed on the piece of paper placed at the gas tank vent tube exit.
- Continue spraying until the drips run clear.
Step II: Preventative maintenance.
- Open the gas cap and remove the key.
- Cover the tank inlet tube to prevent dropping parts in the tank. A large rag or towel is best as it will also help catch small parts and prevent them from falling on the floor (where they can be lost).
- Remove the two brass screws located on the bottom of the gas cap that hold the latch mechanism in place.
- Remove the latch mechanism. Note: there are loose components in the base that covers the latch spring.
- Inspect the latch, clean as necessary and then set aside.
- There are five small loosely mounted springs on the underside of the gas cap. They can be left in place for this operation or removed and set aside for safe keeping.
- Remove the small metal collar located on the end of the key cylinder’s male connector. The collar acts like a bearing between the key cylinder and previously removed latch assembly. It is loose and easily lost. Slip it off and put it aside for safe keeping.
- Hold the gas cap vent assembly in place while removing the two short screws located on the base of the gas cap vent.
- Wiggle the gas cap vent assembly back and forth to loosen it from and prevent damage to the gasket which is glued to the gas cap cover.
- Inspect the gas vent gasket for tears or bulges. The outline of the venting path depressed into the gasket should be visible (this is normal). Gently wipe with a clean cloth. Inspect the cloth used for signs of debris.
- Remove the small round plastic check valve/liquid separator located on the underside of the gas cap vent assembly (a pair of small needle nose pliers works well). Be careful not to damage the silicone valve covering the base of the check valve. This is the valve that allows air to enter the gas tank to relieve negative pressure. Remove the check valve gasket as well and place it aside.
- Inspect and clean the check valve. Pay close attention to cleaning the tiny 90 degree elbow which leads to the vent hole.
- Inspect the silicone valve located on the underside of the valve. It should be soft, pliable and moving freely.
- Inspect the small holes behind the silicone valve. Clean as necessary.
- Inspect the silicone check valve mounted in the gas cap vent assembly. This valve helps relieve positive gas tank pressure. It should be soft, pliable and moving freely.
- Inspect and clean the gas cap vent assembly air channels and vent hole. Pay special attention to the very small vent hole leading to the 90 degree elbow in the small round plastic check valve/liquid separator removed previously. This tiny hole is easily blocked by debris.
- Reassemble in reverse order.
- Repeat Step I frequently (at least once a year) to keep the gas tank vent line free of debris. Keeping the gas tank vent line clean will help prevent debris from reaching the gas cap vent assembly where it can easily block the air channels or small vent hole.