Fuel tank cleaning

[Big T]

My friend let her bike sit and there's crud (not rust) in the tank
What's the best chemical to rinse it out with?

[chuck hahn]

I use Acetone and be real careful not to let it get on the paint. But i would think something like Berrymans fuel system cleaner dumped in and swished around would dissolve the skanked up fuel scum in short order.

[wymple]

Start with a little good old gasoline, then go to vinegar. Stick a hand towel or something in there and use a stick to wipe around the inside as much as you can. I use the vinegar and stick an air nozzle in there with a wrap around the opening and blast things around that way.

[Nessism]

POR-15® Cleaner Degreaser is made specifically for removing varnish. it's non acidic as far as I know. That fuel system cleaner stuff chuck recommends should work too.

[chuck hahn]

Maybe get a roll of blue painters tape and completely cover the tank before using any chemicals. Do all you can to protect the paint. Im just used the cleaner to clean the injectors for my newly acquired GPZ 1100 project. 10 minutes of soaking and they flushed out some pretty nasty residue.

[jdvorchak]

I usually use plain white vinegar to clean tanks. It will never hurt the paint or anything else on the bike. In fact if you spill it, where it lands will be clean. Then after cleaning and flushing the tank with gallons of water, I put in a hand full of nuts bolts and shake that around a while. Do yourself a favor. Before you put the nuts/bolts in, count them! That way you know if you got them all out with the magnet on a stick. Now after a cleaning like this, flash rust will form in a matter of hours. So I make sure to put the tank into use with a full load of gasoline to prevent the flash rust. If I can't fill the tank quickly I put in a few quarts of diesel fuel and shake that around. That will coat all of the surfaces and prevent the flash rust. And when you're ready just drain the diesel out. No need to get every last drop out. It will not hurt a thing when you fill the tank with gasoline.
Remove the petcock so the nuts/bolts don't beat it to death.

On my 80 850G before cleaning:


After

[jdvorchak]

One other point that I just thought of. If you pour out the vinegar into the yard, it will kill the grass! So I pour my used vinegar into a covered 5 gallon bucket and put the cover back on. Then you can use the old vinegar to clean or de-rust other things like the shocks. Put them in there for an hour and like magic the rust in between the coils will clean right off. Plus it's a degreaser so it will clean all of those hard to reach spots under the coils.