odd carb goo


my 85 BMW R80 was not firing on the left cylinder yesterday
good spark but I put in new plugs anyway
pulled the carb bowl: almost dry
no fuel flowing into the left carb
pulled the fuel lines, no problem there = lots of flow
removed the floats and needle valve
there where 6 "things" blocking the flow at the needle valve
I blasted them out and they looked liked grains of sand but I crushed them with my fingers; kind of gooey
nothing in the right carb
I replaced the fuel lines
runs great again
I've never seen that "goo" before


I'd wager to guess some gasket material, tank liner, or perhaps a small bit of hose dissolved in the gas, or maybe just the new ethanol horseshit. Or if someone used some gasket material on the carb gaskets and didn't wait for it to dry completely before assembly.


Gaskets are good
No sealant used
I've owned the bike since new
Filters are not blocked
I suspect the fuel lines deteriorated so I replaced them


Interesting. I suppose it could be the fuel lines, seems odd that it would only be one though. When you removed the fuel lines did they seem extra brittle, or squishy?


I was using urethane fuel lines and they appeared to be in good condition; still pliable and only a bit discolored
I had to cut them off as they had hardened a bit
they didn't look like they were coming apart
I blame it on Obama


an article in the latest issue of Classic Bike comments that ethanol will cause fuel lines to break down. now I really do blame it on Obama


Street Tracker
an article in the latest issue of Classic Bike comments that ethanol will cause fuel lines to break down. now I really do blame it on Obama

That could certainly be the cause of the goo.

Not that it matters, but simply so you are aware and can place the blame appropriately, the use of ethanol predates the Obama administration...it was actually under W when the switch from MTBE to ethanol-blended fuels occurred:


Part of what I do professionally is provide environmental forensic support to clients and we've used the presence - or absence - of MTBE as a line of evidence in supporting insurance claims. In all honestly, you need to blame the toxicity of tetramethyl lead and the recalcitrant nature of MTBE for the switch to ethanol-blend fuels. Ethanol certainly wasn't the first choice as an octane booster/oxidant for fuels blenders....




Friendly reminder from the guy payin' the bills... keep the political shit outta here.


Cafe Racer
The problem with ethanol is WHEN there is water evident, and water always finds a way, you get phase separation.

Phase separation: http://www.lcbamarketing.com/phase_separation_in_ethanol_blen.htm

If you can ensure there is no presence of water, ever, none, zilch...from the refinery to the terminals to the carriers and then to the gas store...then you will have zero problems with ethanol. All we need now is a fool proof way of blocking water to ever finding gasoline and if you find that means, then don't share it with anyone and market it...you will make the Koch brothers look like hungry begging peasants.


So I replaced the fuel lines on my BMW and Triumph T140 with ethanol resistant polyurethane lines last year.
I was out on the Bonneville and was about 20 miles from home when I smelled gas.
The fuel line between the carbs was leaking. It fell apart when I poked it. Polyurethane is not ethanol resistant.
I took one of the fuel lines off to make a new balance tube and the line was hard and stiff. I did manage to affect a repair and have replaced all the lines with black nitrile tube ie auto fuel line.
I hope that fixes the problem



Found this reference which lists chemicals & solvents and what rubber O-ring materials
resist respective chemicals. McMaster-Carr used to have a shorter chart for
the various chemical resistant gloves they carry but I couldn't find it.

Link to page 3, according to this EPDM or neoprene has better
resistance to ethanol than nitrile:

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