1979 GS750L Fuel Tank Replacement

[Drivadesl]

I am in process of removing the existing POR15 lining on the existing tank as it has developed some rust spots. over the years. It has been soaking in MEK which I've sloshed around for a few weeks, but doesn't seem to be doing much to affect this coating. If someone can suggest a different solution that's more affective I would be much appreciative.

While I'm messing with that I wanted to find a new tank to use to run the bike and do some additional tuning on it. I had fashioned a pony tank, but want something with some capacity and better looks to be more "semi permanent" and rideable. Is there a source for a new tank that would fit the bike ? I don't mind it being temporary and even modifying the mounting if needed. I can find a used tank, but was hoping to start with something not rusted out as I already have one like that.

I looked on eBay and there are small new MC tanks you can buy, so may have to go that route if necessary. Was hoping to tap into the knowledge base here for anyone who can recommend a new tank that fits, or fits with some modification.

Thanks!

 

[Nessism]

High strength paint stripper will soften the Por-15 tank liner. It's not fun to work with, and you need to let the tank vent, otherwise pressure will build up.

 

[Drivadesl]

Thanks Nessim. I found this:2-MIN. REMOVER ADVANCED GEL (sunnysidecorp.com). I tried a small patch below the fill spout, left it for two hours, so on return it definitly sofftened the coating. I was ready to start on it, when my friend offered his boroscope to try. Figured it would be good to have for a before and after status. Pictures below.

Overall the tank looked good as these were the only actual rust spots I could find. ​Wondering if I could just spot treat it.

 

[Nessism]

You can try to spot seal. Worst case, strip later if the repair is short-lived.

And regarding sealing in general, I'm not a fan of how Por-15 suggests that their paint will seal over rust. It may, for a while, but it won't long term. I always derust to the greatest extent possible, then assess whether the tank needs lining, or not. Many times it doesn't.

 

[JoeNashville]

You can try to spot seal. Worst case, strip later if the repair is short-lived.

And regarding sealing in general, I'm not a fan of how Por-15 suggests that their paint will seal over rust. It may, for a while, but it won't long term. I always derust to the greatest extent possible, then assess whether the tank needs lining, or not. Many times it doesn't.

I agree, complete de-rusting and the stage prior to etching the tank. Personally I only use POR as a tank in very good condition anyway. I use something more stout like Caswell's for a typical OG tank that needs signigicant rust removal and prep.

 

[Rob S.]

Didn't that famous Canadian Neil Young say "rust never sleeps"? Cover it up, and I bet the best outcome could only be a short nap. Because if there's someone who knows about bikes, it's N. Young. :livid::livid:

 

[Suzukian]

I loosely wire brushed the hood of my 1973 MG. Midget that I was restoring from the inside out (I plan to replace it with a fiberglass one). The hood was all surface rust. I scuffed it with a wire brush, and used Rustoleum Rust Sealant (Remover?). It turns the surface black. They recommend leaving a light layer of dust. After the hood turned black, I sanded it down smooth, and applied some of the Rustoleum stuff to some spots. I then primed the hood. That hood has not rusted in any spots, despite being outside for 10 years. The car is now in my Barn with a hopped up blueprinted engine, side draft DCOE Webers, Forged pistons, 10 degree Duration Kent cam, shot peened Rods, etc. It does 115 mph, which is fast for one of those car. I agree with Nessism​ , get the rust out of there. The Rustoleum is actually a slow drying Cyanoacrylate (Crazy Glue) and suspends the rust particles. The rust will grow again, especially sandwiched between the tank sealant and the metal. The Electrolysis will continue from the polarity differences of the rusty, and metal from the tank under the sealant, and entropy will accelerate the condition.

 

[Rob S.]

Suzukian: It's called the enter key. It starts a new paragraph. Learn it, use it. It's our friend. (Especially us old guys.) :teapot:

PS Show us pics of the MG, please.

 

[Suzukian]

Me learn engrish as 2nd langwich.

 

[Rob S.]

Remember what Linus said about the Great Pumpkin? That's the way I feel about MGs (and Triumphs) that aren't 'British Racing Green'. Don't tell me, 'cause I don't wanna know.