Fuel & Intake

1985 RZ350

Fuel Tap

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RZ350 - Fuel Tap Rebuild

The fuel tap can easily get jammed up with lack of use or a rusty tank. To remove it you'll need to remove the tank from the bike, drain the tank, and loosen the two Phillips head screws that hold it in place. Mine were really rusty and I had to use vise-grips to get them to turn.


The fuel tap has a three position knob, and a spigot for a vacuum line to the right carb, and another for the actual fuel flow. The three positions are "res" for the reserve tank, "on" for the main tank' and "pri" for priming the system. Basically the prime function allows the fuel tank to drain as if a faucet was opened. The on and reserve functions will only allow fuel to flow when the motor is producing a variable vacuum which operates a vacuum pump on the backside of the tap.

The backside of the tap has 5 screws which hold the cover on the diaphfram pump. It isn't really necessary to check the vacuum pump unless you suspect there is a problem. My tank and tap were both in such bad condition I decided to take it all apart to be sure.

Once the screws are removed, carefully lift the back off the tap. The diaphram may or may not come off with the back. If it stays on the tap a small spring will be visible. If it comes off with the back, a small rubber o-ring around the central metal plunger.

On the bottom side of the tap is a small plastic sediment bowl. Unscrew the bowl and check the sealing o-ring which should remain in the tap body.

Remove the finger knob by removing the small grub screw in the side. Then remove the aluminum face plate with the on, res, and pri text on it. At this point I made a mark across the rotating stem and the backplate. I also made another mark between the backplate and the body. Fuel taps are very easy to rebuild incorrectly and these lines will help make sure it goes together correctly.

Unscrew the backplate by removing the two small Phillips screws. This will expose a warped metal ring which exerts pressure on the rotating part and helps it seal against the rubber seal inside.

Finally remove the rotating fuel stem. Mine was stuck to the rubber seal which should remain in the tap body. I had to peel it off the rotating part but it looked OK to re-use.

I had to peel it off the rotating part but it looked OK to re-use. The rotating face was covered in rusty old dried gasoline

The o-ring around the stem was broken and brittle. This will be replaced when it is rebuilt.

I had to peel it off the rotating part but it looked OK to re-use.

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