Fuel Tank from Hell GS650G

[Guest]

I started work on de-rusting the fuel tank and wow, might have been a lot easier looking for a used tank.. But almost done now.. This is the process I used thus far, might be informative for someone later on..

Though the outside of the tank is nicely ding and dent free with light scratching on the paint (tank is going to be repainted, no worries), the inside of the tank was a disaster.. heavy rust and an ancient failed tank liner treatment that made it a royal pain in the assets to get it cleaned out.

Looking at the inside of the tank, I can see thick crusty rust covering everything, right up to the filler neck.. the gas cap was very difficult to remove let alone turn the key. I was able to finally remove it, clean it out, used a nylon rotary wire wheel to remove the clumps of rust from the innards and soak everything in Evapo-Rust until it was all bright and shiny.. The chrome cover on the cap buffed up nicely.. almost too nice to put back on the tank.. Ok that job is done, key operates the pawls nicely and I can actually insert and remove the key without junk covering the key..

The Petcock was encrusted with a lot of weird shyte.. some of it brittle, some of it like a red silicone caulk material.. so badly rusted there's no point of salvaging it.. Its been strongly recomended to get a new one instead of wasting money on a rebuild kit as apparently they don't always work properly.. tossed it away.

Getting the fluid out of the tank was a pain.. no petcock drain so off goes the petcock and drain it through the hole.. which clogged up with that reddish gloop material.. and stink? enough to knock the proverbial buzzard off a **** wagon at 50 yards.. Picked a bad day to do this in the garage as it was howling high winds and bitter cold outside but had to open the doors to vent out the stench.. wow, really? wtf?

Once the majority of the fluid was removed, I removed the fuel sender.. and again.. wow, really? The photo shows what it looked like after chipping off some of the crusty junk off of it.. rust, gloop and what must be a dead squirrel wrapped around it.. I decided to forego the fuel sender and cut it off the blanking plate.. (no fuel gauge? no problems, don't have one on the other bike either, can live without it).. Now that the tank is open and can see inside a little more, it was a distaster inside..

Tossed in some acetone and swished it around and nothing.. hmm came out a little pink.. I used tuct tape to seal the holes after tossing in broken safety glass inside and tumbled the tank in the dryer for a couple of hours.. now stuff started to loosen off inside. A lot of the rust chunks came off.. The stuff looked similar to pumice rocks.. broke apart reasonably easy. Once the tank was cleaned out and all the glass / debris removed, a close inspection showed what the problem was and why this was more difficult than it should have been to clean out..

(I used the red tuct tape as it glues down nice for a good seal and comes off easily, and turned out to be rather resistant to acetone for the period of time I used it)

The failed tank liner trapped rust underneath it, but remained flexible enough to defeat the glass.. but the glass got the crusted rust off the liner now exposing it to the acetone that I then sloshed in afterwards. Now the liner was coming apart and dissolving properly.. It took several good sloshings with fresh acetone to get the stuff out until the acetone came out lightly pink.. it wouldn't come out completely clean so I guess 'good enough'.. already went through a gallon of acetone thus far.. (photo of red fluid in bowl is how it came out after the 3rd sloshing..) Is the red colour indicative of a particular product?

Then into the wash basin and rinsed out with scalding hot water until the water flowed out clear.. a drain trap caught a lot of rolled up red caulk like material that poured out of the tank.. Once the hot water came out clean (tank hot to handle!) I swished it out with 90% rubbing alcohol to chase the rest of the water out.. a shop vac aided with the rest of the drying process..

And the inside turned out clean bare metal, no flash rusting.. Resealed the openings with tuct tape and poured in a couple of bottles of Evapo-Rust, periodically rolling the tank to catch any rust in the nooks and crannies, and what ever I couldn't wire wheel off under the filler neck..

And there she sits until the Caswell kit comes in this week.. drain the Evapo-Rust, rinse with 90% rubbing alcohol, dry it out and away we go.. At least THAT part should be relatively straight forward.. ish?

Photos:

I couldn't get a camera angle to the show the worse of it..

http://www.eastcoastphotos.com/gs650g/picture078a.jpg

Fuel sender unit after knocking off big chunks of pumice rock like material..

http://www.eastcoastphotos.com/gs650g/picture0146.jpg

Acetone after 3rd sloshing of the tank to clean out ancient failed tank liner..

http://www.eastcoastphotos.com/gs650g/picture0148.jpg

[tom203]

I admire your perserverence- that was one ugly tank. My old xl350 tank is not as bad,but I chickened out and just got used one instead. You can pick up sending units off ebay cheap- the gauge is handy to have- real handy if you have a minature tank capacity like my "L" model.

[Seaking]

Thanks, fuel gauge not really a big item for me as this little bike will be a local rider only, using the reserve to get to a gas station.. Just got the Caswell kit in the mail today.. might hit it tonight or tomorrow and finish it up.. Once the Caswell goes in, won't be able to get a new sender in there anyway, well not without more work than I wanna put into after all this recent kerfugling..

[Seaking]

Had to take a peek into the tank tonight to see how well the cleaning process is working out and I should say I'm impressed.. Considering what it was like at the beginning, it's now looking quite decent.. this is with just 24 or so hours of soaking in Evapo-Rust, rotating the tank every once in a while, sloshing it around back and forth etc. I tried taking a bottle brush to the inside to catch any left over failed liner but the brush could only bend so much once inside the tank, so I resorted to twisting a large Scotch Brite pad at the end of a long coat hanger wire and managed to get into most corners of the tank, pulling out additional debris in the process. I think I'll leave it soak overnight again and finish it off tomorrow..

What I plan to do is take the tank indoors and flushing it all out with scalding hot water to get everything out of the tank, a good rinsing.. Then back to the garage for a 90% alcohol rinse and drying immidiately before doing the Caswell liner job.. Should avoid a lot of flash rusting.. I had previously tried the vinegar thing but the flash rusting was almost instant.. Hmm? With the Evapo-Rust I have more time to work the tank..

So with fingers crossed, everything goes well tomorrow and I will end up with a clean sealed tank, ready for blasting and paint.. and not have to go hunting for another tank ergh!

[Seaking]

Finally got the tank finished off today.. After a few days of Evapo-rust soaking, turning the tank every so often to get into all the nooks and cranny, it was time to get it sealed.

Rinsing the tank out with hot water, managed to get more junk out of the tank, albeit just small little bits of the PO's failed tank liner. Ran water till it came out clean and clear. The hot water heats the metal making it quicker to dry and evaporate any left over dribbles. Chased anything else left behind with 90% rubbing alcholo. Could have used acetone but didn't want to deal with the fumes and disposal.

Using the Caswell kit is quite easy. Just have to ensure a good mix and proper measuring and using it in proper temps. Since I didn't have any other tank projects coming up, I made it simple and used it all in one batch (removes the measuring error out). Pouring the stuff in the tank and resealing the hole at the top, then rolling the tank around for 30 minutes to ensure full coverage.. You get an idea how the stuff flows when you pour it out of the mixing container.. but take your time helps get it everywhere..

And then came the one issue I hadn't thought of at the time.. how to pour it out! The filler cap hole has a big lip area on it that won't allow a lot of the mix to come out of, and the petcock hole is on a flat surface and only so much of the comes out of there. Hmm So figuring that the rust would reform where the fuel isn't touching, I opted to have more / thicker coverage on the topside of the tank and allowing more of the mix to pool around the filler neck to get under the hard to reach spot.. Once the mix that was left over in the mixing bowl showed signs of stiffening up, I let the rest of the stuff in the tank pour out. At this point, it's a matter of choice as to where most of the mix is going to sit and not affect anything.. I opted for the right side of the bottom of the tank.. When you sit the tank down to cure, what ever mix that is left still flowing will accummalte to the lowest point..

The mix gets rather thick and hard after an hour and allows you to trim off any access that might be streaming or drippiing from various spots. Luckily, the stuff coated the inside of the tank well from what I can see. I had the petcock bolts installed at time of rolling the mix around and removed as the mix was curing, thereby ensuring I can still get them in when everything hardens.

Something quite interesting in the process is the amount of heat the mix puts out while curing. Using a laser temp gun, the tank was at 71'F when I started, but reached 134'F in some areas where the mix was thickest when resting to cure.. that didn't last long though..

So all in all, I would have to say this was an easy process to go through, just have to be patient is all.. as badly rusted as this tank was, I'm quite impressed with how it turned out on the inside.

Point to notice, if you have a choice of getting the clear or coloured version of Caswell tank liner, go for the coloured version as it makes it a lot easier to see where it goes and doesn't go inside the tank.. The clear version looks quite wet when you look into the tank, so that helps, but the coloured stuff would have been just that much easier..

Now, all I need is a new petcock.. and paint the outside of the tank..

Cheers

[hikermikem]

Thanks for the nice write-up... My son & I will be doing pretty much the same thing to his 1100LT tank as soon as it warms up in northern VT

I've always used POR-15 in my tanks, but understand the Caswell stuff is perhaps thicker & better in tanks with pinholes & such...

My experience with EvapoRust (although not in fuel tanks) is the metal takes a bit longer to rust up, but it will rust completely in fairly short order.

[Seaking]

The POR-15 is quite thin and if the metal isn't perfectly clean, I've read that the product might not adhere properly, causing subsequent failure.. The Caswell pours in like honey, sticks to the surface and clings to it as you roll the tank..

As soon as I had rinsed the Evapo-Rust out the tank I could see flash rusting right away, but that would be of little concern with the Caswell as it will cling on top of that little bit of rust..

I've used the Evapo-Rust on a lot of parts on this bike project, it eats away at the rust and keeps it away for a while until you can properly treat the metal later on.. Good stuff, Canadian made..

[spyug]

I am a big fan of the Caswell stuff mainly because you don't have to go to the extreme lengths that friend Seaking has. At least not with regards to rust. It covers, bonds to and encapsulate rusty surfaces. Get the old liner out but don't fret so much about the rust.

The first time I used it I made the mistake of making one gigantic batch as he did but I forgot to take into consideration the airtemp and it flash cured before I could spread it fully through the tank. As a result I ended up with a big blob of the stuff right where the sender unit was supposed to reside. so no sender unit in that tank.

I've used it twice more and in both cases did a two coat application with a close eye on air temps and it worked very well.

As mentioned, it is great for pinholes as well but larger holes need some other filling first. For those situations, if they are not too large ( say up to a quarter) I have plugged with "plumber's epoxy putty" before the application of the liner. The putty is easy to use and shape and is impervious to gas. while it may not be as good as a welded or braised patch it is safer and easier to do for the home mechanic.

Good write-up sir. Thanks for sharing and enjoy your new leak free tank.

[Seaking]

Thanks Spyug, when you say flash cured, do you remember what the ambient air temp was? I could see THAT being a huge hateful situation to be in..

I may have been very OCD about getting the rust out but it was also an excercise to see what works and what doesn't. Getting the old liner out was more effort than the rust.. Acetone did the trick, though in this case, a lot of work..

Now that the mix has solidified in the tank, I can tell where it pooled inside the tank when tapping against it. Next time I do another tank with it, I'll be more conscious of making sure it has an exit path to allow more of the product to escape from the tank..

Cheers