Hi Brian,
No, without the petcock to act as a cut off valve the tank will always have to be drained before being removed (which is what I am going to do right now when I stop typing on this wee computer) so, largely for this reason, I will re-fit the petcock when I reassemble everything.
OK, Farquhar, if it is aluminium hydroxide how did it get in my petrol tank?
You can always replace it with a more reliable manual one.
Could be several ways, but without >much< more detail from you it’s impossible to determine.
OK,
Tank is off. I could see more of the grey gunk just inside the hole where the petcock mounts so obviously some careful cleaning is in order. Fuel filter is still in place and I would describe its removal as “tricky”. Will go for round 2 tomorrow (I didn’t have all of my tools to hand today).
Not sure what more detail I can provide regarding the grey gunk. The bike has only done 15,000 miles and I would say that its general condition indicates it has always been well looked after. I am sure that I have never dropped any kind of foreign body into the tank although this could have happened before I owned it. The condition of the tank is rust free and excellent so its seems unlikely that it has ever had any kind of tank sealant introduced.
That’s more like it.
Fuel can contribute Aluminium Hydroxide to clog filters especially if methanol rich. Has it been to Scandinavia? You have now declared its preowned hence you don’t know if one of those stupid fuel saving tablets was dropped in, or anything else for that matter at some point. The paste may be aluminium filings. Can’t remember what the pump impeller is made of, the filter on my 1100 sport ie is alloy so erosion /corrosion is possible. The pressure return valve (is there one??) from the injection feeds will send any suspended solids back to the tank but we can assume the “comb” filter and fuel filter will pick up the worst. What I would do is:
A) carry on with cleaning and change fuel filter. Flush tank, lines and any other bits you feel confident to do.
B)recommission with fresh fuel (and leave the sov in place!!)
C)if all is good recheck the tank filter for more gunge after say 200 miles in case of recurrence. There may be residual but unless there is significant wear somewhere and there is not many items it can come from it will be fine.
Have you checked for ferrous content of white powder - magnet?
15000 miles over how many years and standing for?
You might find this Wiki extract of interest:
Methanol, just like ethanol, contains soluble and insoluble contaminants.[11] These soluble contaminants, halide ions such as chloride ions, have a large effect on the corrosivity of alcohol fuels. Halide ions increase corrosion in two ways; they chemically attack passivating oxide films on several metals causing pitting corrosion, and they increase the conductivity of the fuel. Increased electrical conductivity promotes electric, galvanic, and ordinary corrosion in the fuel system. Soluble contaminants, such as aluminum hydroxide, itself a product of corrosion by halide ions, clog the fuel system over time.
Thanks for the info Farquhar,
I haven’t taken the bike to Scandinavia but it did spend 6 weeks in Italy this summer and this was when I first experienced problems with the tank filler cap expanding and, later, the strange whining noise currently under discussion. I will check out the ferrous content of my grey gunk/white powder tomorrow.
Very interesting talk here, agree that these days you cannot underestimate contaminants in fuel…permit me if you will to send you a foto of the float bowl of me old Duke, fairly convinced this was water ingress, but illustrates that you can’t be too careful with fuel systems. PM you email address…guykate2013-12-28 21:40:25
Local chainsaw workshops recommend dumping fuel if not used in a month due to ethanol content and its affinity for water whilst standing and hence corrosion /tide marks in tanks and possibly float bowls and the like. This has been discussed elsewhere at some length. If I get my pal Stewie on a relatively sober period over the festive season I’ll ask him to research this topic. He is a LR offshore inspection engineer and corrosion is his game. He also has a crippling LM Mk3.
Edit: found this old Toadygraph alarmist anti-cheese eating run away merchant article…
ethanolMad Farquhar2013-12-28 22:37:47
Put the pic up if you like Gavin…
That Torygraph article is a bit too alarmist. The bio fuel in France is clearly labelled as E10, the normal as 95. But as blind drivers seem to regularly fill their petrol cars with diesel and vice versa, I suppose anything is possible.
I Certainly would.
As for the noise i have a feeling that the filter on the petrol tap will turn out to be the culprit.
My reasoning is that on my 97 Cali 1100i ( manual petrol taps ), if i turn on the ignition then start it and have forgotten to open the fuel taps i get a very strong whining sound from the pump area as it is trying to pump fuel but has no access to what is in the tank.( almost as if the pump is in vacuum )
This whining noise is NOT the normal whine that you should hear for a few seconds as the FI system self primes.
The very second that i open the manual taps the noise immediately goes but certainly would not if i left them shut. I don’t forget to do it very often but my previous Guzzis have all had electric petcock’s fitted so initially a return to manual taps was strange but for me preferable as their is less to go wrong.
If Richard 63’s bike has a partially clogged fuel petcock filter he may well be putting the fuel pump under excessive strain just as i do when i forget to open the taps. Try breathing through a straw!
I would check that petcock before doing anything else and ensure that the tank is thoroughly clean before reassembly. I would also as a matter of course renew the fuel filter to ensure everything is given a chance to work properly.
In all honesty i would replace that petcock with a manual one as Brian suggests. Far more reliable.
Manual Tap
Good luck Darryl
DazGuzzi2013-12-29 08:39:54
GuyKates float bowl with what appears to be some of Nigellas favourite icing sugar. 
Its amazing to learn the bike still ran.Mad Farquhar2013-12-29 09:28:52
Cheers MF.
T’is the float off the front carb on my old bevel which as you will know is very exposed. Pretty sure water is the culprit, occasionally I forget to cover the bell mouth. Manifested as lots of spitting at low rpm. …
Was crystalline tho not to difficult to remove… …guykate2013-12-29 09:55:49
The crystalline stuff…did you remove mechanically (carefully) or find / use some product to dissolve it? Carb cleaner?
Carb cleaner and a brush x
Another update,
Fuel filter is now out (and I have now recategorised this job as “very tricky”). Shining a torch inside revealed no sign of the grey gunk but I will be replacing it anyway. Guests have arrived so no time today to continue the cleaning of the tank and petcock or to check out its ferrous content. Thinking back to my touring in the summer; there were couple of times I seriously under estimated the journey time and ended up riding in a zombie like state at silly-o-clock in the morning. I could easily have filled up with E10 petrol by mistake. (If I had stopped at one of those supermarkets where you fill up your own containers with wine from a pump it could have be filled with E12 H2O78 the state I was in.) Any advice from your corrosion expert friend greatly appreciated Farquhar.
…and another update.
Have cleaned out the tank, petcock and accessible fuel lines as best I can. New fuel filter has arrived (I went for a sytec SSF 3021 - just £8.96 on Ebay)so I can put it all back together when it stops raining. Fortunately, the comb on the petcock seems to have done its job as most of the grey gunk was concentrated there. Whilst I had the tank on the bench I decided to remove the decorative rubber trim around the tank seam as a fellow owner had told me it traps water and rusts the seam. Sure enough, some rust was under there. I have cleaned it up and applied “Kurust” prior to Hameriting and refitting the trim with exterior quality silicone sealant. I would advise anyone who has this kind of decorative trim on their tanks to take similar action before the rust bug gets too far advanced.
A final question for you experts; the fuel filter was attached using three aluminium crush washers. The new filter has been supplied with copper crush washers but these are not exactly the same size. Meanwhile, in my box of bits, I have nylon washers exactly the same size as the original aluminium washers. So, aluminium, copper, nylon or does it not really matter that much?
i would go with the copper
I agree with Keith. I did the same with my rubber trim too, but didn’t put silicone on -seems a good idea. I did put silicone on the back of my rectifier/regulator though, after carefully cleaning up the corrosion between the resin and the ali -and I put an extra Earth on it.
Hi everyone,
Research on the net suggests it is down to the tightening torque. High torque use harder copper washers, medium torque softer aluminium washers, nylon washers can seal with just hand tightening. Given the difficulty of accessing the fuel filter I considered it a medium torque situation and refitted with aluminium. Acid test will be whether it p!sses fuel out when I get the tank back on and fire it up!
If anyone is about to do the fuel filter change here is my take on it:-