Condition inside the gas tank

All my motorbikes, Z1R, GPZ11, 2 x FJ1200 have their fuel tanks cleaned and coated with KBS tank paint, The Z1r has had this done 18yrs ago with no problems. It feels and looks like a ceramic surface
(I do not have anything to do with the KBS company)

30% is the strongest I'd go. Hot water to dilute is good. I don't know exactly how long it will take to remove the rust but I suspect less than one hour.

Nessism wrote: 30% is the strongest I'd go. Hot water to dilute is good. I don't know exactly how long it will take to remove the rust but I suspect less than one hour.

I will try monitor with a camera during the process

Today have I used phosphoric acid inside the tank.
1. Degreased the tank inside.
2. Flushed with clean water.
3. Added 30% phosphoric acid and turned the tank around each 3-4 minutes for 40 minutes.
4. Flushed the tank for a good while with fresh water, tried to get all water out.
5. Added Isopropyl alcohol turned the tank around for a while, dropped it off..
6. Spayed alot of WD-40 and turned the tank aorund..
7. Used hair draier on the filling whole and let the hot air come out from the level switch and petstock.

I`m 90% happy with the results...

Video`s form after the treatment:
streamable.com/retoz
streamable.com/0kgbt

Video`s form before the treatment:
streamable.com/52t3l
streamable.com/8icrv
streamable.com/sxxdf

Is these good enough for a long term condition... ?
I see many use tank sealer, but I have heard that is really bad if the paint start falls off in the tank...

For fuel tank storage. I would consider using Snowmobile Fogging Oil. .... wd40 kind of evaporates.




...

Looks like the tank still needs a little work. A very nice start though. The brown spots are either rust or fuel varnish. I'm not sure which, but it's critical for you to figure what they are because the process for removal is different. For rust you just need a little more time with the phosphate sauce. If they are varnish then you need something like carb cleaner to break through that.

Good luck and keep going...

I would put some handfull of little nuts or steel marbles with phosphate acid into the tank and shake him like hell to loosen the rust particles.

I would put some handful of little nuts

don't be an idiot like me and throw in some random handfuls from the "misc nut can" and find when you are using a magnet to get them out that some of them were brass :pinch:

Point 1.
Condition inside the tank, old gas ? corrision?
I have tried to take some better videos and photos, please see below:

Videos:
streamable.com/s2bu7
streamable.com/939zf
streamable.com/d8mgv
streamable.com/jn9tf
streamable.com/f3e1w
streamable.com/75whq

Photos:


Point 2:
For me it looks like a combination of old gas and corrosion ?
I`m afraid I damage the nice painted surface on the outside using nuts and small metals parts to remove the corrosion on the inside?

What todo ?

1. Carb cleaner ? just spray all whole box inside the tank and then what ? must I do some mechncial to remove it ? or can I just turn the tank around same as with the Acid ?
2. Flush the tank with clean water ?
3. Add Acid again, 30% or go higher ?

Thank your for your advise !

Maybe a stupid question, but what do I gain by getting the metal 100% clean from corrosion and old gas ?
Will the corrosion of the metal go slower and the tank will be fine for longer period ?
After I installed a inline fuel filter has the big gone smooth for a season.

Thank you all for your advise and input !

Nessism wrote: Looks like the tank still needs a little work. A very nice start though. The brown spots are either rust or fuel varnish. I'm not sure which, but it's critical for you to figure what they are because the process for removal is different. For rust you just need a little more time with the phosphate sauce. If they are varnish then you need something like carb cleaner to break through that.

Good luck and keep going...

Thank you, me plan is try both carb cleaner and acid.

Carb cleaner, will purchase two boxes today, and just spray all inside the thank, can I just roll the tank around? Not need mechnical clean it with a brush or something? Don’t know how to get access? After just flush with water?

Acid, shall I just go for 30% mix these time or higher? For how long time? Just investigate with camera under the process?

Thank you.

I've enjoyed very good success by putting some links of various size chain and sheet metal screws and other miscellaneous ferrous nuts and bolts inside a dry tank, wrapping the tank with cushions/pillows/beach towels/whatever to protect the tank's exterior finish, and then tumbling the cushioned tank inside a clothes dryer on no-heat for an hour or so - repeat as needed - to obtain a smooth rust/crud-free interior.

It's easy, safe and not messy.
And far more efficient than struggling to shake the tank by hand (if wanting to attempt that for a few hours - ouch! ). :pinch:

Anyone who has polished stones by tumbling can relate to this method.

When finished tumbling, can rinse with water, then rinse again with common household rubbing alcohol, allow to dry (may use a hair dryer), and immediately spray/coat interior with WD40 or marine oil fog to protect until filling with fresh gasoline.

Good Fortune! .

Patton wrote: I've enjoyed very good success by putting some links of various size chain and sheet metal screws and other miscellaneous ferrous nuts and bolts inside a dry tank, wrapping the tank with cushions/pillows/beach towels/whatever to protect the tank's exterior finish, and then tumbling the cushioned tank inside a clothes dryer on no-heat for an hour or so - repeat as needed - to obtain a smooth rust/crud-free interior.

It's easy, safe and not messy.
And far more efficient than struggling to shake the tank by hand (if wanting to attempt that for a few hours - ouch! ). :pinch:

Anyone who has polished stones by tumbling can relate to this method.

When finished tumbling, can rinse with water, then rinse again with common household rubbing alcohol, allow to dry (may use a hair dryer), and immediately spray/coat interior with WD40 or marine oil fog to protect until filling with fresh gasoline.

Good Fortune! .

Don`t have space in my dryer or washer....
Will try the plan above tomorrow.