Is This Varnish?

[foureyes]

I was lucky enough to take ownership of Leslie's fine build the other week and on my shakedown I noticed a strangle rattle coming from the XS750 Fuel tank...

Draining the tank removing the filler cap and stripping the petcocks enabled me to take a look inside. I found what I first thought where a number of rocks sliding around inside. Most of them are far to large to get out via the filler or petcock holes so I was confused as to how they got in there.

After buying a flexible grabber I managed to get a few of the smaller pieces out which revealed that the objects where not rocks but something more like an agate. Its a deep orange in colour and when rattled around forcibly will start to disintegrate into a dust which can then fall out of the petcock holes.

There's a large amount left in the tank (probable a couple of chocolate bars!) and removing it by shaking will take me until next year so I'm wondering if anyone in the forum knows.....

• Whether the 'rocks/agate' is fuel varnish?
  
• How to remove varnish of this size if that's what it is?
  
• A reputable welder/paint company that can cut a hole and then re-weld the fuel tank..
  
• A source for some XS650 frame 'ears' so that I can revert to an XS650 tank that I have spare.

As always any answers and feedback welcome.

 

[weekendrider]

It kinda looks like dried pine or cedar sap.
Does it dissolve in gas? If so it may be easier to let it dissolve and pour out as a liquid?
If you decide to go the "put something in the tank and shake to break it up" route, consider it is easier to fish out a length of small link chain (think dog collar chain or porch swing chain) than shake out 500 individual bb's, nuts, bolts, rocks, etc..

Someone cleaning a frame up might could supply the tank cups for the stock tank. Try a classified?

 

[fredintoon]

Hi 4eyes,
like WER sez, drop a yard of dog-leash chain in there and make like a maracca player.
Then remove the chain and suck the debris out with an oval section aluminum (or even cardboard) tube taped onto a vacuum cleaner.
Yes, the tank bottom can be cut open and then patched but not without damaging the paint job.
As I remember it, the XS750 tank plug & ear tank mount set-up is the reverse of the XS650s so yes, you could swap the frame back to stock but then the XS750 tank wouldn't fit it?
OK, this may be my aging memory not working right or if it's so why didn't Leslie try it?
But:-
The XS650 stock frame has ears that are open at the back.
The XS750 stock tank has ears that are open at the front.
The XS750 tank tunnel is wide enough that the ears clear each other on assembly.
All you need to fit the XS750 tank onto the XS650 frame is two sets of back-to-back paired hockey pucks?

 

[gggGary]

I'll guess it's chunks of some ancient try at a tank liner. A sugar in the gas "prank" 20 years later?

 

[Higgy]

I'm thinking that looks like way too much material for it to be varnish of any kind. Golly, a whole tank of gas would not even produce that much varnish! I'm guessing its sugar, but I'd also be receptive to the tank-liner idea.

 

[fredintoon]

I'm thinking that looks like way too much material for it to be varnish of any kind. Golly, a whole tank of gas would not even produce that much varnish! I'm guessing its sugar, but I'd also be receptive to the tank-liner idea.

Hi Higgy,
if it's sugar 4eyes will see if the chunks that came out dissolve in water
(I would really NOT advise a taste test) and if so a gallon or so of hot water will wash his problem away.
If it ain't water-soluble and it's chunks of degraded tank liner there's several aggressive solvents that'll work to dissolve them.
Alas that they are all pretty good paint strippers, too.
There went the paint job again.
Say "sod the paint" and cut the bottom of the tank out?
Say "sod the problem" and fit in-line fuel filters?

 

[foureyes]

I wish I had read the replies before going back up to the workshop tonight!

I hadn't thought of the sugar option but that or a tank liner failure make the most sense as there is loads of it...

I'll make a cup of tea tomorrow and see if it dissolves. If not it's dog chain time with some ear defenders.

Already said goodbye to the paint sadly but it makes too much noise under braking to ignore with inline filters.....

Thanks for all the advice everyone. Invaluable as always :-D

 

[foureyes]

Well it doesn't dissolve in water but a long stir in a cup of boiling cleans it up enough to make it look much more like the resin that it probably is.

Sod the paint and bust a hole in the tank it is then!

 

[angus67]

No!! If you can melt it out with boiling water, try that first

 

[fredintoon]

Hi 4eyes,
don't get medieval on the tank just yet even if the stuff ain't water soluble.
Tried welding up a gas tank one time.
All I got from the attempt was an enormous respect for guys who can make welds that don't leak
First try sucking the chunks out through the filler hole with a narrow nozzle on a shop-vac.

 

[NONclow]

If you're gonna trash the paint anyway, or aren't bothered by a little paint work, try sloshing some lacquer thinner (a few cups worth), through it a few times.