AT Fuel Pump: to recap

[PerfectStranger]

Hi guys,

There is another option... and it only costs 1€.

This is what I did on my bike (pics are of a friend who taught me this modification):


The solution consists in adding a diode at the end of the coil, it serves as a "freewheeling" and allows an induced current to flow without its destructive arcing. I put a diode that supports approximately 7-8 A:



You have to solder the anode to ground on the output switch (negative side of the coil) and solder the cathode to the blue wire striped black feeds the coil + side:





Then you must isolate the metal part of the diode to prevent it from coming into contact with a piece of metal pump. For that just use either some thermo-retractable sheath some hot glue (applicate with a gun) which can also be used to "fix" the diode

and… That’s all!

Below is an image which shows the condition of the contact which is now stabilized after 14000kms:




Here is a video of the standard fuel pump:



Here is a video of the standard fuel pump + diode de roue libre:



Here is the reference of the diode I used : FAIRCHILD SEMICONDUCTOR|RURP860|DIODE REDRESSEMENT DOUX 8A | Farnell France

Hope this helps

Hi Fabien, can you please post a drawing of the schematic on how to connect the Diode?

I couldn't really figure it out from your pictures/explanation.

Merci bien!

[GSPD750]

Hi Fabien, can you please post a drawing of the schematic on how to connect the Diode?

I couldn't really figure it out from your pictures/explanation.

Merci bien!

I'm not Fabian but I'll chime in...If you look closely in the first pic you will see the letter "A" (anode) and the letter "K" for (cathode) Don't ask me how you get a 'K' out of cathode but thats the way I see it.

The yellow 'jumper wire' comes from the cathode side of the diode marked "K" and goes to the blue/black wire. In the 2nd and 3rd pic the diode is flipped around upside down which may be confusing. The other solder joint which Fabien explains is of course the anode side of the diode marked "A" which goes to the ground on the output switch (negative side of the coil).

That's the way I see it.

[PerfectStranger]

So no wire cutting, just the + wire stripped a bit to solder the diode in there.
Right?

[GSPD750]

So no wire cutting, just the + wire stripped a bit to solder the diode in there.
Right?

Correct. But you will need a short piece of wire to 'jumper' from the cathode side. In Fabians case he liked the colour yellow.

[PerfectStranger]

Thanks!

I've been reading this: Transient voltage suppression diode - Wikipedia, the free encyclopedia

Is this similar to what Fabien used?

They look rather different...

[fabienlegall]

Correct. But you will need a short piece of wire to 'jumper' from the cathode side. In Fabians case he liked the colour yellow.

You got it guys

Not sure about the yellow being my favorite colour though

[PerfectStranger]

And what about the type of diode?

Can you please help?

Thanks

[Bonzo]

I did this on the weekend to my bike and a friends bike. It was easy peasy. I did mine with the pump attached to the bike but my mate had removed his pump as it needed a good clean and some attention given to leveling the contacts which were badly pitted after 20,000 miles.

I was a lot easier to do it off the bike.

You can get the diode in the UK from RS components but I think you need a account and I had to buy a pack of 5 as that was the minimum order but that only cost about four quid.

Make sure you insulate well as all your work will be for nothing as the pump won't work at all if there's a short.

[fabienlegall]

And what about the type of diode?

Here is the one I used: FAIRCHILD SEMICONDUCTOR|RURP860|DIODE REDRESSEMENT DOUX 8A | Farnell France

[XR Mad]

I did this on the weekend to my bike and a friends bike. It was easy peasy. I did mine with the pump attached to the bike but my mate had removed his pump as it needed a good clean and some attention given to leveling the contacts which were badly pitted after 20,000 miles.

I was a lot easier to do it off the bike.

You can get the diode in the UK from RS components but I think you need a account and I had to buy a pack of 5 as that was the minimum order but that only cost about four quid.

Make sure you insulate well as all your work will be for nothing as the pump won't work at all if there's a short.

You dont need an account to buy over the counter in RS anymore i like this diode solution got to look at my pump and think i will do this fix myself