So i have just bought my new bike, a honda cm400, for when i innevetably manage to pass my mod2 and have noticed that the previous owner has used some petseal type tank sealant in the past and it is now looking a tad bubbly and like its peeling away inside.

i was wondering how worried i should be about this, the tank doesnt leak and there is an inline fuel filter so hopefully noting will get into the carbs but its still presumably something i should sort out.

my first instinct was just to keep an eye open for a better condition spare, but these are probably not all that common so im wondering if there is a clever/effective way of restoring this one, stripping out the old sealant and welding/brazing the original leak.

Any advice is greatly appreciated!

Well, this doesn't immediately help your situation, but I used POR15 sealant on my Ducati fuel tank. Dead easy to use (especially if you have an external fuel pump), and having spoken to guys who restore bikes and cars it's really the dog's balls for sealing fuel tanks. Lasts longer than the fuel tank...

Seal it in a day, leave for 4 or 5 days to cure, then plumb it all back in. Job done for good.

That just leaves you to get rid of the petseal.

i was hoping there would be a better sealant about, perhaps a small wire bresh on a flexible pole could be worked around inside there to get all the loose stuff free followed by some solvant to melt away the remainder

I can't ride the bike at the moment anyway so it taking a while to cure things or let solvents work wont be a problem, although i would imagine petseal must be pretty hard to melt chemically

Well, how about Petseal remover right here?

You can read about my experience with POR15 here.

Not tried the petseal remover, so I couldn't tell you what it's like.

Petseal is great but needs the tank to be totally dry before it's done. The Petseal remover should deal with any variety of tank sealant, my son in law used it on some other stuff he'd tried unsuccessfully.

I only have experience of petseal but I guess the same applies to all of them, the tank needs proper preparation and definitely needs to be totally dry of fuel, ie left empty and open for a week or two.

Hmm - I emptied the tank, left it overnight, and then got on with washing it out. The POR15 kit comes with "marine clean" (I think it's called), so the tank's all clean and prepped first of all/ But all the treatments must be removed before applying the sealant. I used a hair-drier to dry it out afterwards (just getting water out at that point), which worked great, but the tank gets really hot. Once it's all hot, leave it for the water to evaporate, and then you can get on with it.

Or that worked for me, at least.

Fantastic! thats pretty much a perfect combo of treatments, i can't thank you enough! great review too it really would have been a shame to lose that tank as other than the dodgy sealant job its in very good condition.

I've not been on that frost restoration site before either, it looks pretty good. I'll order these bits up and let you know how i get on with them as soon as they arrive.

Cheers

I can Second that POR15, I did my GPZ tank a couple of years ago, great stuff!

Well my por-15 kit is now in the post. i havent gone for the petseal disolver yet as i read somewhere that M.E.K or actone will also cause petseal to break down and flake away so im going to try them out as their alot cheaper

One way to get rid of all of the loose stuff is to add a handful of small stones (ones with sharp edges work best) and then shake the tank, will take some time, but will clean the inside of the tank.

Just make sure you get all of the stones out when you have finished.

We used to use a good handful of flint stones off of some ones drive That with some diesel used to get rid of a load of flakey rust and such crud. Afterwards we used to rinse with about half a gallon of parafine. To dry, and vaporise any leftover parafine we used an old hoover tube on the exhaust of the van. we used to do this to enable us to gas braze any repairs on the tank as well.

My por15 came today so i started cleaning out my tank, unfortunatly the guy who petsealed it also let a big old pool develop which came loose as soon as the MEK got to work, so now i have a 6" by 4" block of solid petseal kicking around in there too im going to leave the mek in there with it overnite so hopefully it will melt enough to be taken out of the filler hole by morning

I like the stones idea too, i might try that if theres much left in there