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Discussion Starter #1
So I am fascinated how my fuel pump damper and hoses turned to black goo. What the hell could make gas do that?

Kay is a red 1990 K75 with an unimaginative name which was parked with a full tank for too many years. Sure enough, Kay's damper took a dumper. Strewed black tarry cottage cheese all about the bottom of the pump sump. Hoses turned to goo too. Split screen. Frozen pump. And when I pulled the injectors, I found that even the lower O-rings had melted a bit inside their holes.

So now I have to figure out how to clean dried black tar from inside those injector holes. Need something to dissolve the dissolved. As it happens, I had a bunch of that crap get stuck on the end of a crappy Stanley chisel when I scraped goo off the old snap ring. Figured I'd test some solvents on that. If I found out what dissolved the dissolved, then I'd know what to use in those holes. Stanley has a plastic sheath. I filled that sheath with various stuff, stuck Stanley in it to soak, then rubbed with a rag soaked in same. Tried PB Blaster, master bolt loosening stuff. No dice. Likewise gasoline, thinner, Goo B Gone, Engine Brite. Nuttin. That goo is tough stuff.

Finally figured I'd try some hair off the dog. Fetched the rubbing alcohol from under the sink. Instant Success.

I am excited. Going to yank that clip collar out of the trash, buy some 180 rum, and prove this theory once and for all. It's the corn juice I'm telling you. It's that effing boondoggle jack the price of meat up starve the third world subsidize Archer Daniels Midland lower gas mileage ethanol horse manure. Only thing that dissolves O-ring rubber into goo.
 

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Kay said:
Finally figured I'd try some hair off the dog. Fetched the rubbing alcohol from under the sink. Instant Success.
Rubbing alcohol (Isopropyl) is different from ethanol, is different from the old methanol (from "gasahol" fame). Ethanol is usually easier on rubber parts than either of the other two (it also tastes better :cheers: ). If you want to do a materials test, put the bits of damper in a jar with E-85 (do a websearch to find a station that sells it near you).

That said, I ride an '86 K75 in Minnesota, which has had 10% ethanol in all the gas since 1997, and the damper is a tad soft, but it doesn't need replacing yet. It's had 13 years on the ethanol gas.
 

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Would be nice to know exactly what causes it as it is a common thread and the theory has been ethanol in the fuel but Rema's experience would tend to dispute that.

I suspect that fuel can be "cut" with any number of additives and I seem to remember Acetone might have been one which is definitely not rubber friendly.

Perhaps it is the percentage of Alcohol in the fuel as 10% may be fine but we currently have an Australian independent politician demanding 22% which may be quite the opposite.
 

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phil_mars said:
Would be nice to know exactly what causes it as it is a common thread and the theory has been ethanol in the fuel but Rema's experience would tend to dispute that.
I could just be lucky. Some questions:
- did riders report the fuel dampers turn to mush before ethanol started getting added (in the late 90's)?
- is it a problem today in states with no ethanol in the gas (I think most states, other than the midwest and Cali, have less than 1%)

I'm also curious about whether long storage has anything to do with it. How could several years immersed in "old gas" be harder on the damper than several years immersed in "new gas"?
- old gas with ethanol will build-up water in the solution (new gas won't have water, and in old gas without ethanol, the water will sink rather than staying in solution)
- old gas will have the varnish coming out of solution. Maybe the varnish plugs pores on the damper?
 

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Kay said:
I am excited. Going to yank that clip collar out of the trash, buy some 180 rum, and prove this theory once and for all. It's the corn juice I'm telling you. It's that effing boondoggle jack the price of meat up starve the third world subsidize Archer Daniels Midland lower gas mileage ethanol horse manure. Only thing that dissolves O-ring rubber into goo.
I couldn't have said it better.... :manure: After riding close to 15,000 Kms through the USA this last couple months and seeing the incredible quantities of corn now grown in your country just so the politicians can pat themselves on the back in the name of self-sufficiency. But I met very few fuel pumps without Ethanol.....! :wtf:

There is a few fuel tests on the net where they tested gas pump and found some with up to 27% Ethanol content.....Yikes! :teeth

I have some of this "Corn Juice" here.....and also some Lambs Overproof 151......I think I'll go drop some O-Rings in it and see what happens....after all this stuff is Lab Quality.....! :) :) :)

But....we need a chemist here, just so we could understand what kind of stuff is brewing in our gas tanks after months/years of storage. :confused:

 

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Discussion Starter #6
heet is neat

Scored some Heet at the auto parts. Heet did the job. Cleaned the goo right off the injector seats. Says right on the bottle: "Contains methyl alcohol."
 

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There are two kinds of Heet I've seen: original (Methanol) and "Iso-Heet" (Isopropynol). Sounds like you got the original. I get a kick out of seeing it for sale at the gas stations here: you'd need to dump-in about one bottle per gallon to make any difference in the amount of alcohol in the tank here. That said, methanol is the worst of the three for materials compatibility.
 
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