Foreign material in my inline fuel filter - what is it?

I have been noticing small pieces of a black material showing up in my clear inline fuel filter. These appear to be rubber, but they may not be. They are relatively large, about the size of a grain of rice.

What could they be?

I am thinking that the internals to my petcock are going! That would not be good. My carbs are not leaking, however that doesn't mean the petcock is good.

 

gremlins...

 

Could be a rotten fuel line??!!
Might be just something from the gas station,n in which case there is why you spent $5.00 for an inline filter....... could have been your float valves getting plugged up!
To check that your petcock isnt leaking just unplug it from the filter and let the hose hang and watch for drops, might take 20 min or so just to be sure. (no open flames here)

 

The fuel line is clear and brand new. Anything from the gas station should get caught in the screen on the inside of the gas tank pre-petcock.

That is why I thought it was internal to the petcock.

I checked my petcock for leakage about a month ago, and it is doing great.

Has anyone ever had the internals disentegrate and end up in your carbs or inline filter?

 

There not bugs? are they .

investigate with a microscope or whatever.....

 

Rust from the tank?
Tank Liner?

Hows the petcock filter?

 

Thats a point HG , the fuel tap filter should stop most getting through!

richard03 see if you have one.[its in the tank]....

 

I thought that all of the XJs had the filter/screen inside the tank?

 

They do but there is more to the fuel system than just the fuel tank. The rubber lines used for the fuel system are a special synthetic type and should only be replaced with a like formulation. The Haynes manual points this out in the fuel section. If you use regular fuel line, it will degrade over time and start to shed material into the system.

 

Worth noting robert:

Ever get gas on a bic type pen? It melts in seconds. There is a reason to use the right type of fuel line.

 

That is interesting.

However, the fuel line between the petcock and the filter is clear, and the bits I am seeing are black.

After thinking about it, I don't think there is any option other that the internals to the petcock or some sort of rubber o-ring disentegrating. I am probably going to rebuild it and see what I see.

 

Once I used a yellow pencil to hold open the flapper valve on a truck to be able to pour gas into it, and it melted the paint off of the pencil in seconds! That was interesting.

 

Richard:

I would agree with you, the only possible source would seem to be the rubber gizmo in the petcock.

I had to replace mine recently, because the metal disk in the petcock tends to chew it up. I can see where the holes in the metal disk could shave off chunks of the rubber the size of rice grains.

Therefore, I use my petcock as little as possible, trying to fill up by mileage before I have to use reserve.

Good luck-
Herb

 

The main component in gasoline that melts plastic is toluene. It is a main ingredient in plastic feedstocks, and also in model glue.

 

I think your petcock internals are crumbling. If you ever had this bike overseas where the gasoline can contain high percentages of aromatics (like toluene) then this could have done it. Cheap gasoline will sometimes use more than normal quantities of aromatics to boost the octane, it's usually off-spec stuff they're trying to get rid of. Buy premium gasoline, it is formulated to more exacting standards and your bike will run better.

 

Posted: Thu Aug 10, 2006 8:36 pm Post subject: Higher Gas Prices for dirty fuel -- BEWARE!

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I'm located near Boston. This time of year the highways are super-busy with folks on weekend get-aways and out-of-stater's passing through for the splendor of the New Hampshire and Maine vacation spots.

Gas is in short supply. I have pulled-in to fuel stops along the interstate and gas stations on the loops of major highways and seen some of their pumps closed because the tanks they connected to are empty awaiting tank truck from the fuel depots.

Motorcycles, personal watercraft, some boats and engines taking a direct feed from their fuel tanks unprotected by a fuel filter are at risk for contaminants and sediment, now.

My Max started acting-up after a gas stop in Boston. I suspected ignition problems and discussed the matter with a close friend who is a busy, certified Yamaha tech.

He showed me a holding area with nearly a dozen bikes all having the same symptom as me. The machines were fueled at places where the supply of fuel had nearly run-out and were contaminated by fuel with containing sediment which is so fine it passes through the petcock filter right into the fuel bowls.

We XJ'er's are at risk for having the carbs get fouled with this stuff and causing the carbs to be removed and cleaned.

Your friends and neighbors with late model fuel injected machines might be, too -- although, most F/I bikes have fuel pumps and lines to the injectors protected by a filter or two.

The "Stuff" I found in the fuel bowls looked like brown mud -- the consistancy of baby powder.

 

I just wanted to let you guys know what I found when I tore down my petcock yesterday.

The 4 hole diaphragm had a couple of small pieces torn out of it, and was cracked in another place. It had not caused a leak yet... The pieces that were in the fuel filter were definitely from this diaphragm.

But, my theory is that it could have caused a leak by allowing gas to leak through the prime "channel". So - I am glad that I caught it!

Two things that are important:
1. I am so glad I have an inline fuel filter. It is clear, so it allowed me to see the bits it captured. So, I avoided a leaky petcock later! Also, it captured the bits that most definitely would have clogged something in my carbs.
2. Apparantly my 4-hole diaphragm was disentegrating. So not only can the vacuum assembly cause a leak, but so can this daiphragm if there are problems.

Thanks for the help guys!