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Suggestions for Cleaning an Aluminum Tank? '89 K75

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New member
I'm looking for suggestion on cleaning a heavily corruded aluminum tank from a K75.

A couple years ago I picked up an $400 '89 K75 with 23K on it. The bike is complete but was sitting outside uncovered and unstarted for 10+ years. I've been going through a thorough restoration--rebuiiling the forks and brakes, cleaning injectors, replacing hoses and seals, etc,--however one of the areas I'm stuck on is cleaning the fuel tank.

The exterior of the tank is in fair condition considering its history, but the inside is a mess. I've pulled the innards including a fuel lever sensor and fuel pump which were coated with corrosion beyond recognition. The fuel pump dampening gasket had turned to gel and had to be scraped out, and the interior of the tank had a light brown coating of corrosion on everything.

The tank also has a very very small less than a drop a day leak.

I've used the POR 15 treatments before to clean and seal gas tanks and they've worked great. That's what I'd like to do with this one, but those tanks had no where near the corrosion this one has. Also, the POR process uses an acid wash to prep the tank for the sealent and I'm uncertain about using acid on an aluminum tank.

Any suggestions for removing the heavy corrosion and cleaning the deposits out of this aluminum tank out? And will the acid wash be safe?

Thanks for your help.

Kontoboy

'99 K1200RS
'89 K75

P.S. I usually post under the moniker "Kontoboy" but that account has been mangled--I'm trying to get it fixed.
 
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Sounds absolutely bonkers, but a guy over on motobrick just suggested putting a handful of drywall screws in the tank, sealing the openings with tape, then very securely wrapping it all up in blankets, also taped together, and then putting the whole mess in the dryer (no heat) for a while.

I make no such recommendation. Just passing along the idea.
 
A safe medium to tumble-clean the inside of a gastank with is glass. Get a piece of broken car glass (preferably a door window) in a junkyard and smash it. It will break into small pieces. Put them in the tank and use the dryer method.
The glass will remove all the debris and corrosion inside the tnak without damaging or reacting with the tank metal. Also, if for whatever reason a piece gets stuck inside, it will not corrode.
 
If you know anybody with a vibratory deburring machine you could borrow a handfull of the little ceramic pieces that thay use. I have heard of people doing this and just shaking the snot out of it by hand. That will test your upper body strength!
Jeff
 
If it were April 1 I'd of thought everyone was pulling my leg, but when I get 3 out of 3 replies suggesting the same thing I've got to take it seriously.

I've got a small piece of tempered glass I can break for the beads, but I think I"ll see what results I get with doing a dance with my tank before I throw it in the dryer.

Now should I use the Cottons, Permanent Press, Delicates or the Fluff No Heat cycle?

I've already gotten hell for washing my shop rags in the washer. The wife needs to be out of the house before I try this.

Thanks for the suggestions and stay tuned--I post back the results.

Kontoboy
 
I do not know for certain and I didn't stay at a Holiday Inn Express last night, BUT trying to clean the aluminum tank by any of the previously suggested methods sounds like it would have the potential of not ending well.

I would believe a chemical cleaning would be less potentially damaging and more thorough. I would phone POR and ask what they would suggest for an ALUMINUM tank. All acids are not the same. Even orange juice is an acid and is used in many effective industrial solvents and cleaners. Let us know what they suggest.



:dance:dance:dance
 
I do not know for certain and I didn't stay at a Holiday Inn Express last night, BUT trying to clean the aluminum tank by any of the previously suggested methods sounds like it would have the potential of not ending well.

I would believe a chemical cleaning would be less potentially damaging and more thorough. I would phone POR and ask what they would suggest for an ALUMINUM tank. All acids are not the same. Even orange juice is an acid and is used in many effective industrial solvents and cleaners. Let us know what they suggest.



:dance:dance:dance

So you're saying he should fill it with orange juice and put it in the dryer?
 
I know repair is a lost art, but years ago, there were number of tank and radiator repair services that will clean out corrosion and repair leaks. Are those places all gone? Has anyone looked in a phone book?
 
You guys laugh. I personally have not opened a phonebook for a few months. Internet search is good for most items, but there are companies and certain businesses that target specific demographics that know their customers do not use internet. Shocking, but true. Sometimes it may still be worthwhile having those brick books around.
 
Actually I do know a place that does radiator repairs--I took a couple of Yamaha YZF750 radiators there a couple of years ago. The one with a leak they were able to repair and the one with crash damage they couldn't.

I'll call POR too and ask what they recommend.

I didn't get the tank in the dryer yet-- I was rebuilding the forks this weekend. The spring in one was broken into three pieces! Now I'm waiting on a pair of Progressive progressive springs.

Rather than tumbling it in the dryer I was thinking of putting some abbrasive media inside, strapping it to a piano dolly and fastening the piano dolly to my reciprocating saw. I'd shake it up a couple minutes and see what it looks like. I can rotate the tank on it's sides and top to get 360 degree coverage.

Kontoboy
 
A quick update. According to the people at POR their "Prep and Ready" acid treatment is safe to use on Aluminum tanks when used as directed (e.g., don't let it soak inside the tank). The did recommend using their "Marine Clean" to prior to the prep and ready to remove residue for the decayed rubbber bushing that held the fuel pump. I had the POR 15 kit and ordered a quart of Marine Clean for $15 delivered.

I also checked the web site of a local shop, Looper Service, that I used before to repair a bike radiator. I haven't contacted them about the tank yet--I want to try my own repair first.

As a back-up I found a K75 tank in Upstate NY on Craigslist and my brother checked it out and picked it up for me. I'll be driving up and seeing him this weekend.

Kontoboy
 
Here's an update--sorry for the late reply. I left the tank cleanining to last after getting the rest of the bike restored.

After some head scratching I decided to go ahead and try POR Marine Clean-- and it worked very, very well. I think my delay in cleaning the tank helped. When I first drained the tank and removed the fuel pump. the rubber gasket around the pump had dissolved into a sticky black goo, but after several weeks of sitting in the garage that goo had dried solid. In addition to the black goo there was also a patina of light brown gasoline residue and bits of broken fuel hose. With some cautious scraping with a variety of tools I was able to able to get a lot of it out. What I couldn't scrape out I hit with carb cleaner and scrubbed and blotted up best I could. All in all I spent a couple hours with my armin the tank just cleaning before moving on the POR Marine Clean.

Marine Clean is POR's water based cleaner--one part of MC with one part hot water. Pour it in an slosh it around, and around, and around, and around ad nauseum. The first batch of dirty MC/water that cme out would have easily qualified for a hazardous waste manifest. (Luckily my county has a drop off site that will take just about anything.) It was pure black and littered with debris. After a thorough rinsing and a second washing with MC and I was amazed--the tank was almost pristine with little evidence of the decade of old stale gas it harbored.

I finished up with the Metal Ready and the POR Sealer per directions, patching a pinhole leak in the process, and I am now waiting the recommended 96 hours for it to dry before installing the fuel pump, sending unit and hoses.

I can't wait--the rest of my Zombie--back from the dead--is back together and hopefully ready to test fire after 15 years of sitting dormant!

Thanks everyone.
 
A safe medium to tumble-clean the inside of a gastank with is glass. Get a piece of broken car glass (preferably a door window) in a junkyard and smash it. It will break into small pieces. Put them in the tank and use the dryer method.
The glass will remove all the debris and corrosion inside the tnak without damaging or reacting with the tank metal. Also, if for whatever reason a piece gets stuck inside, it will not corrode.

Let me tell you that EM Simon knows his stuff. Do what he says.

He may be a little whacko but he knows his stuff!! hehehe
 
My K75 Resurection

I'm also stripping down a 1992 K75RT fuel tank to access the level of corrosion, and identify any pinhole leaks. I've identified several on both sides of the tank so far. As preciously discussed, the description fits mine to a Tee.

I liked reading the results of the POR-15 process, any idea what the total cost of materials were? Living here in SoCal, I got to be so careful with the disposing "waste" products; I receive a quote from a local radiator shop to perform a caustic hot tank and acid tank cleaning process, then perform a seal coat of the interior (guaranteed not to leak again ;)), $150. Decision time... your comment please.

Now I must be procuring the replacement internal components in anticipation of the previous step. Could someone point me in the right direction where I may find/purchase a complete fuel pump replacement kit and Fuel Level Sender Unit.

Appreciate your feedback folks.
 
I'm also stripping down a 1992 K75RT fuel tank to access the level of corrosion, and identify any pinhole leaks. I've identified several on both sides of the tank so far. As preciously discussed, the description fits mine to a Tee.

I liked reading the results of the POR-15 process, any idea what the total cost of materials were? Living here in SoCal, I got to be so careful with the disposing "waste" products; I receive a quote from a local radiator shop to perform a caustic hot tank and acid tank cleaning process, then perform a seal coat of the interior (guaranteed not to leak again ;)), $150. Decision time... your comment please.

Now I must be procuring the replacement internal components in anticipation of the previous step. Could someone point me in the right direction where I may find/purchase a complete fuel pump replacement kit and Fuel Level Sender Unit.

Appreciate your feedback folks.
The hot dip tank will also damage and/or remove the paint on the tank. That's fine if you're going to repaint it anyway, but if the paint was decent, I think I'd go with the POR treatment. They do make good stuff (don't get the actual sealer on anything you don't want it on, it won't come off..)
 
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