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POR-15 or KBS Cycle tank sealer

katcon85

New member
I brought home my second airhead today, a new to me- 1974 R75/6. Not as pretty as my (restored by PO) 60/6 but it has 1/2 the miles and the engine runs very nice. The gas tank is a rusty mess though- that's first on the list.
So which sealer should I use? This site seems to mostly stick with POR, but the guy I bought the bike from recommended the KBS, and it has some good reviews.
My plan is to start with electrolosis, move on to hot water/soap/fish tank gravel, then do the cleaner/de-rust and sealant from which ever company I decide on.
Has anyone got any experience with the KBS sealer?

thanks
Kat
matching 74 monza blue R60 & R75
 
Caswell is another option - http://www.caswellplating.com/restoration-aids/epoxy-gas-tank-sealer.html

I just used Caswell (in June) on a rusted out Benelli tank that I modified for fitment on my Aermacchi, I can't say enough good things about it, from ease of use to how it's holding up. I've heard equally good things about POR-15, but haven't heard of the other one you mentioned. I did a general write up of my experiences with caswell @ http://symphonyofshrapnel.blogspot.com/2013/06/caswell-tank-sealer-meets-benelli.html
My only complaint about it was that the sealant was clear, but I wound up finding out later on that you can buy dyed versions (I think they make a black and a red), the red might be a good option if you're looking to replicate the look of the stock BMW tank liner.

Kurt mentioned Kreem as a last resort, but I would never even consider that. A buddy of mine used it on a brand new fiberglass tank with the proper prep and application, Kreem turned into a bladder, then broke apart, then the ethanol fuel ate through the tank. He actually wound up repairing the tank with the Caswell (it will actually seal up holes) and that's how I found out it when I was working on my tank
 
I used the POR tank treatment when renewing my R65LS tank - worked like a charm - but you really need to follow the directions as easy to screw up the paint on the tank (in case you don't plan on repainting)
 
Another POR-15 user here that is completly sold on their products. Besides using their motorcycle tank kit I have done a horse trailer, flatbed trailer, and the frame of my 87 Airstream frame. Years later, they are all holding up really well with NO MORE RUST progression.

A good point above about protecting the paint of whatever you are using it on from damage when using the various cleaners. For the R90 I went to the box store, HD, and got some plugs to fit in the fuel outlets and made a diaghram of an old innner tube under the gas cap to seal the inlet. Worked for me with no leaks as one does the various slosh, coat, and shake steps.....I poured the residue on my gravel road/barnyard/storage area with no resultant effects or explosions..........If you live in a neighborhood, city, or suburbs I would pour it in some throw away cans and take them to a proper disposal outfit........Good stuff.......God bless.......Dennis
 
Red-Kote is the best as far as I'm concerned

Used it in a /2 tank that had several pencil tip sized holes in it oh about 13 years ago and it hasn't leaked a drop or peeled away from the tank wall yet. Its red but has a little more shine to it than original red sealer. I used Por-15 to redo a tank that had been kreemed and it has bubbled but not torn away from the tank wall. Red-Kote is simple to use but you have to be real careful if the outside of the tank is a nice original paint or a repaint, you should do it before you paint the tank unlike me who waited until after Holt BMW painted and striped both I did.
 
I have been very happy with the POR15, though it is a PITA to prep for it. Since it takes a weekend the task is best paired with some really slow barbecue meat smoking!
Not sure about the other ones mentioned, other than the Kreem, which when I used it was worse than useless!
 
Red-Kote!

I haven't used Red-Kote for a motorcycle tank, but have used it to seal many outboard motor tanks, including the mid-50's Johnson and Evinrude pressure tanks. I've never had a problem with it; it goes in, stays stuck to the tank and just plain works!
 
Haven't tried the others so I can't offer a comparision...

...But that bit of POR-15 liner that I spilled on my work boots (leather) and on the floor
of my shop (vinyl tile) a few years ago shows no sign of lifting!!! Hate to get it on your
skin...
 
I buy KBS from the shelf at a KOI AP store near me & their line is much the same as POR-15,etc.& works just as well. Save on pstg vs. sales tax. There are discounters online but shipping is high on paint products.There are some lengthly tank seal threads on ADV & having read them & the links it gets cloudy as to whats the best. Seems to be several camps as to best choice-I will add that there are comments from persons that have done hundreds of tank as compared to the few I've done posting in the threads I mention-see "The Garage" or Airheads there.
 
I am one of the few who does not believe in using any tank sealer/treatment/coating. A thorough cleaning and afterwards good maintenance by keeping a high fuel level when parked and/or fogging the tank when stored has worked quite well for me. And I have several bikes with metal tanks that don't get ridden more than maybe 3 or 4 times and a total of 300 miles per year.
 
I am one of the few who does not believe in using any tank sealer/treatment/coating. A thorough cleaning and afterwards good maintenance by keeping a high fuel level when parked and/or fogging the tank when stored has worked quite well for me. And I have several bikes with metal tanks that don't get ridden more than maybe 3 or 4 times and a total of 300 miles per year.

Finally, someone I agree with on this subject!!

Unless the tank actually has a leak at a seam or somewhere hard to get to, I haven't seen the need for the tank lining paint/coating.

I have heard also, that a little bit of oil/gas additive will neutralize the acidic nature of the gasoline and add some protective lubrication to the inside of the tank and helps lube the upper end of the engine too!

Mike - you rock - for an old geezer!
 
I would disagree with the no lining approach. I think it's going to be difficult to keep a tank that full all the time. My bad experience of course is my fault. My R25/2 came to me with a fresh paint job on the tank. I first discovered that it had a small seam leak. I noticed the inside of the tank was a very nice steel color...not a single hint of any rust and/or coating. I figured the PO must have had it cleaned up before the paint job. But I had to fix my leak...so I just went the route of dropping a little of the Caswell sealant exactly where it needed to be. Worked great.

Move ahead to my engine rebuild. The tank was only about 1/2 full of gas when I removed it. I didn't think much about it and set it aside while I focused on the engine. Months later, I reassemble and noticed the rust build up inside the tank. I can see the line where the rust stops because there was fuel below it. Now I'm facing a de-rust and reline all with a nice paint job on the tank.

So, I say you have to protect the tank. I can't say how long one could go with bare exposed steel before it's important to put more gas in there to cover it back up. But it would seem that any time the bare steel is exposed, it will begin to rust. Maybe only a little, but it's going to do it and eventually it will need to be taken care of.
 
I'm with Kurt

I've had the pleasure of cleaning and lining two /2 sport tanks that had Holt paint and stripes applied before I bothered to check for leaks or a poor Kreme job, yup I'm a little slow on the lesson learned thing. If you even remotely think the tank has a leak or flaky / loose rust then shame on you if you don't address it before you make nice and shiny with new paint and stripes. I'm gearing up to make a custom /6 tank for a project and its getting the Red-Kote treatment after the welding is done and the finish primer goes on.
 
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