Fix the fuel pump every few days?

Last year, after many years of trouble-free operation, my fuel pump started the continuous clicking when the key was turned on. I found the fix here on the forum (What to do when your fuel pump clicks like a SOB) and tried it. The first time I did it, it worked for several months, then started clicking again. The next time seemed like it worked for a couple of weeks before acting up, and this last time it worked for two days... The next time I take it apart, I'd like it to fix it for good.

Are there replacement rubber diaphragms available, or should I start looking for a new pump?

I've never been able to come up with a source for the two little rubber diaphrams. I wish someone would. I've had my pump apart a time or two as well.

I wonder if there's an aftermarket source for a fuel pump? I've had mine apart recently and it didn't last long.

Some guys are using a Mr. Gasket fuel pump, but the fittings are a pain in the butt. It's 5/16" in and out, and our pump is 5/16" in and 1/4" out. Plus that Mr. Gasket doesn't make the awesome clicking noise, it just runs when the key gets turned on. I wonder what other bikes our pump was spec'd on...

Wait - its not supposed to click a bit? When I flip mine on I can hear the pump and vboost wirring for a second and then its silent.

The factory pump clicks because of the diaphragms. The Mr. Gasket one is different.

Wait - its not supposed to click a bit? When I flip mine on I can hear the pump and vboost wirring for a second and then its silent.

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Yes it does click till the float bowls are primed up..

If you turn the key more than once, It actually sounds like its pressurizing the bowls till it can't go any further, (till the rubber float valve stops when the float bowls are filled to their set level).

Mine primes for about 2.5 to 3 seconds then stops. If I rotate the key again, it click for about .5 second then stops.

One time I did a test to see how long the pump will prime the system if there was a fuel leak.
I opened the little drain plug at the bottom of one of the carbs to release fuel pressure and simulate a fuel leak, then turned the key.
It clicked for something like 6 to 7 seconds then turned off. Fuel was shooting out of that drain plug.
Out of curiosity, I turned the key on again, It did the same thing clicking for 6 to 7 seconds.
I then closed up the drain screw and re-cycled the key, This time it took about 4 seconds to stop.
Re-cycled the key once more and it only clicked for .5 seconds..
So IMHO,, it sounds like the pump primes up to a certain pressure, then stops.
If it primes longer, it's either trying to refill the bowls from a depleted state (peeing gas in or around the carbs), or its not holding the pressure after its been pumped, which can be the little rubber diaphragms inside the pump.

Please... Don't let me get started about what this damn Ethanol is dong to our rubber parts. Especially on parts that flex as their normal operation.

They made these pumps right up to 2008. I would think the easiest & cheapest way to go would be to buy a used one (with theoretically lower miles/years than yours - esp a 1985 year) and swap it in. Sound be fine for many more years, no?

Those small diaphragms or used to come in Chevrolet carburetor quadrajet kits. It's been many years since I have worked on cars and the diaphragm may be too large or too small. But they sure do look similar to the one's I am referring to.....

alorio1 said:

Those small diaphragms or used to come in Chevrolet carburetor quadrajet kits. It's been many years since I have worked on cars and the diaphragm may be too large or too small. But they sure do look similar to the one's I am referring to.....

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The one's I've seen in the GM quadrajet kits are quite a bit larger in diameter..........but incidentally are the very same size as what is needed in my aging hand-held vacuum pump.

Sellers on ebay seem to think their salvage pumps are worth nearly as much as a new pump from Yamaha, so if I have to replace the thing it probably won't be with one of those.

I'm thinking about making a new rubber diaphragm as a trial the next time I pull the pump apart... just have to come up with something about the same thickness that's fuel resistant.

I have some shower pan liner from a recent bathroom remodel, and I have various types of gasket material. If I can find something will survive in a container of fuel for a few days, I'll punch out a disc and install it in the pump.

Another option might be a small snap ring or o-ring or something else to help keep the current rubber disc from popping out of position.

I'm willing to play with it a little bit before I install one of the low-pressure automotive pumps I have laying around.

jfeagins said:

The one's I've seen in the GM quadrajet kits are quite a bit larger in diameter..........but incidentally are the very same size as what is needed in my aging hand-held vacuum pump.

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Get a hole puncher and punch out one of these, it has the rubber tit already on it........

alorio1 said:

Get a hole puncher and punch out one of these, it has the rubber tit already on it........

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If I remember correctly, the rubber tit is too large of diameter also.

Maybe this will be of help:

http://www.acmerubber.com/vitsheet.htm