Fuel tank re-lining?

[SeaBeeRider]

I recently acquired an 82" Nighthawk 750 with only 8800 miles on it, but the fuel tank is shot.  I can pop the cap and scrape rust off with my fingers.  It also looks like that the previous owner lined the tank, but not very well.  I want to reline the tank, but do not know if I can get rid of the last hack lining job.  I dont want to put some solvent into the tank and end up with some goo that is impossible to get out all over the place. 

Does anyone know if the tanks from other engine sizes of the 82' or 83' models would fit to my bike?
Thanks in advance.

[Bad Boy]

Check out this thread
http://nighthawk-forums.com/index.php/topic,3082.0.html

[ROJ]

The only tanks that will fit your bike are the ones from the 1982-1983 CB750SC. They mount differently than the tanks on the other CB750's of the same years. I believe the POR-15 and KBS sealers will take off any sealent in the tank as well. I'd read up on them a bit, and there are a few people on here who have used them and have reported good results, and some who have had trouble with them. From all the reading I've done, I'd go with one of the 2 mentioned and  whatever you do stay away from Kreem, I have not heard anything good from anybody who has used it, it peels after a few years and needs to be re-done. That may be what the tank was lined with.
 Oh, and  to the forum. I also have an '82 750 and absolutely love it.

[SeaBeeRider]

Thanks a bunch guys.  I've already put an inline filter in place and hopefully she makes it with no real issues to the end of riding season and then I can have a nice winter project.

[gammer]

As ROJ has mentioned, I've used KBS and it works great. Just follow their instructions to a 'T' and you'll be good.
And a tip for whatever brand you use:
-Use a hair dryer and some patience for drying the tank out between cleaning. It can't have any moisture in the tank whatsoever, before sealing.

[SeaBeeRider]

Ive got a plan for drying out the tank in between, I already have a setup that I use for drying out my snowboarding boots/gloves.  I'm pretty confident that I can do this project, just not looking forward to the removal of the old, crapped out, liner that is in there now.

[Brittles]

From what I understand a relining of the tank should be done as a last resort only. The tank I'm using had some rust and I cleaned it with vinegar. It still looks somewhat rusty inside (nothing close to what it was), but I make sure to always keep the tank full of gas when not riding and so far so good. Checked (and cleaned) my petcock and tank screen after about 500 miles and sediment was minimal.

[socalhawk]

Mine has also been coated poorly, rust came back and contaminated valve seats. now I'm blowing fuel out my carbs. and have to redue the head.

How well does the vinagar work on rust removal?  why not use an acid for radiators?

[coffee_brake]

Muriatic acid will clean the rust and funk out of that tank very well. Wear eye protection, dump in a big cupful and DON'T put the cap on, and swirl it around in there. It will eat all the rust out and leave bare clean metal. Then you go about treating the tank (I love POR-15, check out the web site for instructions on the proper steps).
Muriatic acid is available at Lowe's and other such stores; it is the stuff you use to clean up and etch concrete garage and patio floors. It's cheap.
If you don't want to use the acid, then you can use paint stripper made for metal.
For the steps where you need to dry the tank, you can first dump in a half cup of mineral spirits (I actually used fingernail polish remover once), dump out the excess, then set up a hairdryer on low speed. Prop it up where it blows in the fill hole and out through the petcock hole, it will dry quickly and you can move on to the next step.

Please don't use Kreem, it really sucks unless you're very lucky.

[jerjohn]

strip the lining using por15 then use electrolysis or what some call reverse electroplating to remove the rust.

[Brittles]

Muriatic acid will clean the rust and funk out of that tank very well. It will eat all the rust out and leave bare clean metal.

Muriatic Acid is a corrosive and will eat metal. I'm not saying it doesn't work, but if the tank has a few pin holes existing or about to exist wouldn't the muriatic acid make the problem worse?

[Brittles]

strip the lining using por15 then use electrolysis or what some call reverse electroplating to remove the rust.

The problem with electrolysis imo is the rust needs to have a line of sight to the sacrificial annode, which is all but impossible given the shape inside a motorcycle fuel tank.

[coffee_brake]

Muriatic acid will clean the rust and funk out of that tank very well. It will eat all the rust out and leave bare clean metal.

Muriatic Acid is a corrosive and will eat metal. I'm not saying it doesn't work, but if the tank has a few pin holes existing or about to exist wouldn't the muriatic acid make the problem worse?

YES you have to start with a healthy tank! Thanks for bringing that up!
My next job is going to be hubby's KLR that is only a couple years old but has a little rust. Muriatic acid will be perfect for it. But really bad tanks..no acid for that.

POR-15 makes a product that strips out old liners. It may work on Kreem but it didn't work on my Harley tank (they come stock with a very good tank liner, wish all bikes did!). I had to use paint stripper.