Condition inside the gas tank

old_kaw wrote: You may want to cut down on the caustic chemicals there Gordone. There are other things out there that will remove the iron oxide without eating the metals in the process. That filler neck is so eaten up that it looks like it is two fill-ups away from crumbling into the tank.

But HEY! All I can do is suggest and tell what I have used successfully on numerous tanks.

Phosphoric acid is a great material to remove rust. You would have to leave it in the tank for weeks to cause any structural damage to good metal. If you were to leave it in for a long time the main thing you would notice is a white residue buildup on the metal which doesn't cause much of a problem anyway.

Oh, and Por-15 and Kreem sealing kits come with phosphoric acid to remove the rust. Not to mention, if you go to an industrial shop that does metal derusting, such as prior to painting, they always have a phosphate tank for that purpose.

Personally, stuff like Metal Rescue or Evaporust are good of course, but I don't use it unless the paint job on the tank is pristine and must be saved. Phosphoric acid won't hurt paint if you remove it quickly, but sometimes $hit happens when you aren't there to watch it.

Por15 and Kreme use the acid as a metal etching agent, and as a rust remover. Once you have the metal etched and all iron oxide is dissolved, then keep using the same chemicals, it goes past etching and goes straight to the metal. Eventually, the metal is not being etched and iron oxide is not longer being removed, and the structural integrity of the piece is being remolded instead. Time to lay off the acids.

To keep using the caustic acids because a little spot / spots are still showing only weakens the already cleaned up sections more. It also works it's way into the seams then trapped. Some may not get completely flushed out in the rinse. A radiator shop that does coatings professionally does not continually soak any parts time after time. If Gordone keeps using acid on this tank, it will soon develop leaks, most likely in the seams that look to be already there. I hope he is looking for a replacement, because it will soon be necessary.

*Note: the acid dips used to be an extreme drag racers thing to lighten up those 16 gauge steel car bodies to remove weight, when just skipping a few pastries would remove the same amount of weight.

old_kaw wrote: Por15 and Kreme use the acid as a metal etching agent, and as a rust remover. Once you have the metal etched and all iron oxide is dissolved, then keep using the same chemicals, it goes past etching and goes straight to the metal. Eventually, the metal is not being etched and iron oxide is not longer being removed, and the structural integrity of the piece is being remolded instead. Time to lay off the acids.

To keep using the caustic acids because a little spot / spots are still showing only weakens the already cleaned up sections more. It also works it's way into the seams then trapped. Some may not get completely flushed out in the rinse. A radiator shop that does coatings professionally does not continually soak any parts time after time. If Gordone keeps using acid on this tank, it will soon develop leaks, most likely in the seams that look to be already there. I hope he is looking for a replacement, because it will soon be necessary.

*Note: the acid dips used to be an extreme drag racers thing to lighten up those 16 gauge steel car bodies to remove weight, when just skipping a few pastries would remove the same amount of weight.

Phosphoric acid is generally quite mild (depends on concentration) and it will take soaking a long time before any serious metal damage will occur. It requires no neutralizing of the acid, just water rinse. I've used it on at least a dozen different tanks, some of which were seriously rusted, and only one time did I have any issues, and that was because there were already perforation holes through the metal.

I'm not passing judgement on Gordone. From what he's said the dwell period is not dangerously long so I see no reason to criticize him. After his first soak job it was clear that more time was needed. Beyond that, I'm not sure. I've soaked tanks for days at a time and the only thing that happened was white chalky buildup thereafter, which I removed with some aquarium rocks in the tank after that. His tank had not reached the same point so I think he's fine.

Oh, and a caustic chemical is a strong alkaline base. Acid is on the opposite side of the PH scale.

I'm not passing judgement on Gordone. From what he's said the dwell period is not dangerously long so I see no reason to criticize him. After his first soak job it was clear that more time was needed. Beyond that, I'm not sure. I've soaked tanks for days at a time and the only thing that happened was white chalky buildup thereafter, which I removed with some aquarium rocks in the tank after that. His tank had not reached the same point so I think he's fine.

Oh, and a caustic chemical is a strong alkaline base. Acid is on the opposite side of the PH scale.[/quote

I am not criticizing or passing judgement I think he's a good guy that wants to save an old kaw in a ferign country, so he's ok with me. if I didn't actually care, I wouldn't take the time to offer my .02. I would just not read it at all, kinda like i did with the 650 idiot and his 15 posts per day on the same subject. it was clear that he just liked the attention from his constant trolling, slamming other people's bikes, then asking stupid questions in his puzzling guessing games -sometimes in the same posting.

Sorry to use the wrong terminology (caustic) to describe corrosive chemicals. It looks like that filler neck has had one too many dips in the Ph punch bowl. lol

Thank you all
I’m grateful people using time on me.

When I have readed about phosphoric acid, my understandig it’s not strong enougf to eat metal...? It only eat corrossion? I have used 30& consentration.

gordone wrote: Thank you all
I’m grateful people using time on me.

When I have readed about phosphoric acid, my understandig it’s not strong enougf to eat metal...? It only eat corrossion? I have used 30& consentration.

I think you are a ok. I just think that the neck was probably already caked up with heavy corrosion when you started, and now that you removed the oxidation, all that's left is thin metal. I highly doubt that any acid is totally safe on metals, but you are correct in your assumption that this is fairly safe to use, especially in the concentrations you are using.

My original comment above was meant as a tongue in cheek somewhat humorous comment, with some seriousness added in to slow down on the corrosive use. I am assuming you plan to coat it, so >I< would go ahead and do it now before any more metal is dissolved with corrosive bath..

This is a 86 Honda Rebel CMX450C that I rescued in 2015. It was also coated over caked rust by a PO. I first removed the coating, then removed the rust with metal rescue. Love the masking tape that disintegrated while the bike sat outside with no gas cap, after that genius had coated the tank.



I replaced this engine with a low mile one I bought in Memphis. Another stray rescue:

New to KZRider and not sure how old this thread is but I have great results with Evaporust. Wont hurt your paint either. I personally don't care for tank coatings. If it's not done correctly you have a mess down the road. My 2 cents.

PACABADA wrote: New to KZRider and not sure how old this thread is but I have great results with Evaporust. Wont hurt your paint either. I personally don't care for tank coatings. If it's not done correctly you have a mess down the road. My 2 cents.

Thank you, Evaporust how is it working?

I have decided to not coat the inside see people saying «leave it for pro» heh.

gordone wrote:

PACABADA wrote: New to KZRider and not sure how old this thread is but I have great results with Evaporust. Wont hurt your paint either. I personally don't care for tank coatings. If it's not done correctly you have a mess down the road. My 2 cents.

Thank you, Evaporust how is it working?

I have decided to not coat the inside see people saying «leave it for pro» heh.

From my understanding, evaporust is about the same as metal rescue. It targets the metal oxide, while leaving other metals untouched through "chellation" whatever that is? lol I just know it won't eat the paint, or the metal. It is kinda pricey, at ~25 bucks a gallon, but I also get 10% military discount at Home Depot. I assume you have one on almost every corner too? <sorry sarcasm!>

As far as coating the tank, after looking at a few of your pics, you may need to coat it because of the eaten up metal in the seams, to prevent it from leaking.

I have seen some coatings that looked great after being applied, but that was done by a professional. My personal experiences is much less appealing, and I have yet to see a tank coating that actually looked like it was applied evenly throughout the interior of the tank. BUT, getting it into the bottom seams is just gravity doing it's thing. Perhaps if you thin it and keep the tank somewhat sealed during the coating process while rotating the tank. Sealing the tank will keep the solvents in the coating from evaporating , and will keep it in a liquid state longer while you roll it around on a furniture moving blanket or carpet scraps. If you use your fancy camera after you do this your will STILL find spots inside that were not coated. You need to try to get it right the first time while it's wet. If you try to re-do the coating after it has dried, it will lift and wrinkle up. Been there, done that too many times. (If it reacts like paint does)

BTW, tank coating is not a fix-all for a contaminated fuel system. It will seal in caked up rust and crud / prevent it from flaking off, but the carbs will still be plugged. (just to clarify for the newbies. with a poor grasp on basic principles)

XS1100 with pinholes galore.



XS1100 Tank after paint.