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Fuel pump -  Membrane renewed

This week I screwed something on Uschi again.  Stimulated by a request in the Goldwing forum on how to repair the fuel pump, I wanted to briefly document the replacement of the membrane. Since I had already renewed a few petrol pumps in the car sector, I expected rapid progress. Well, but the friends from the land of the rising sun were not planning any repairs to the pump and structurally prevented the membrane from being removed. But something like that is even more irritating and since I was horrified to discover that the membrane of the pump was cracked and hardened, a solution had to be found. In 2008, a screw once described the project in an old thread in the American Naked Goldwing forum. So get to work and document the whole thing.

The fuel pump was quickly removed.



The five M5 screws are also quickly loosened and the inner life with the two non-return valves comes to light.


Since the membrane was riveted to the tappet, I carefully ground off the riveted head. Always in the back of your mind that if the worst comes to the worst, Honda will call the princely sum of 170 Ocken for a new pump.


sanded carefully until the upper membrane disc came loose


I then had to use the screwdriver to loosen the lower diaphragm disc. Always make sure that the disc is not bent. Otherwise it can happen that the pump is not tight.


a spring and a seal appeared underneath the plate. The seal ensures that no petrol gets into the oil circuit if the membrane is leaking.


here I laid out all the parts in the order on a board. Otherwise I feared that I would no longer be able to put the pump together.


Since I can no longer rivet the push rod again, I have to find another solution. So I decided to close the whole thing with a small screw. The diameter of the push rod is 4.5mm and so an M3 screw should do the trick. It was still in my possession somewhere.

Since the push rod was not firmly in the pump, I had to fix it to drill the 2.5mm hole. So I made a precision template.


Since the push rod turned after drilling, I found help in a pair of crimping pliers that I recently bought from a discount store.


I mastered the hole without the drill penetrating the push rod and also remaining intact. Then replaced the drill with an M3 tap and tapped the rod.


Since I couldn't find a repair kit or a suitable membrane in the vastness of the internet, I had to rethink. Finally, I found what I was looking for in a Russian seal for a Volga's fuel pump diaphragm. Here is the link for everyone who has the same problem to solve: ... wolga.htm l

the material has the same strength as the original membrane and is also fabric-reinforced.


Using the old membrane, I then drew the new membrane on the sealing material and punched the 5 mm holes for the screws with the punch pliers. Cut out the membrane with scissors.


Punched the hole for the push rod and checked if everything fits.


The whole thing is now secured with the said M3 screw after I had previously dripped a drop of screw lock into the threaded hole.


After reassembling the pump, I was able to check if the pump worked again. Without further ado, put the nozzle for the petrol inlet in your mouth and operated the pump several times. A negative pressure built up immediately.

I'm in good spirits that the pump is delivering petrol again.

And to support the pump, an electric pump is installed, but it only runs when the oil pressure light is on. That is, when the engine is not running and the carburetors are already being filled cleanly.

In retrospect, I thought that I could save the centering step for drilling.

After I've sanded the riveting flat, just enough to still hold the upper diaphragm plate in place but the push rod is flat, center punch it clean. Use the old membrane as centering and fasten it with the 5 screws without the cover. Then, on the one hand, the push rod cannot rotate and, on the other hand, it is nicely vertical.

This makes drilling and tapping much easier.

After tapping, then grind off the rest and remove the diaphragm with its top plate. the lower plate can then remain in place.

Just replace the membrane and reassemble everything and fix it with a small screw.

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