Topic: Gastank 1, Raul 0

[Raul CB750K1]

Well, the gastank won the first battle but it won't win the war. After all my careful sealing the tank still leaks. At least now I know it doesn't leak at the welds, but at the seam. The tank is composed of two halves (upper and lower) made of pressed steel. Looks like the seam is leaking, so I have to swallow my pride and treat it from the inside. So what's best, POR-15 or Kreem? Do you know any online shop?


That's what happens when you buy modern bikes....     My CB750 never had this problem in 34 years.


Raul

[Raul CB750K1]

But man, how can I know that a new one will not give the same trouble in the future? Mine was perfect until a couple of months ago. The leak is so tiny, it doesn't even drop. It's some kind of "sweating", I don't find it dangerous by now. My CB750 head leaks way more than my GZ250 tank. I think there should be a way to fix it, once and for all. I'm telling you that if the tank had a bad dent where it seems it will break soon I will replace it, but I think there should be a way to fix this. After all, this is a forum of wrenchheads. We are not here to discard things as soon as they start go give trouble....   


Raul

[Terry in Australia]

G'Day Raul, sorry to hear (or see, I suppose) that your epoxy job was a dismal failure, I've used Kreem and it worked well, the coating is quite flexible, so I wouldn't be frightened to use it, but I have heard of it coming off, mainly due to poor preparation.

For mine, I'd try the POR15, I have read a lot about it on my other favorite website, and everyone that has used it raves about it.

There's a company in the US that professionally repairs rusty tanks, probably not what you want mate, but an interesting read nonetheless, here's a link:

http://www.gas-tank.com/bike.htm 

Cheers, Terry.

[mick750F]

   Here you go Raul, direct to the source.  http://www.por15.com/

Mike

[Raul CB750K1]

Thank mates, I'll have a look. I'm not concerned about the peeling because the modern petcock can deal with it. The filter is the aspiration tube so the debris goes to the bottom of the tank.

The epoxy worked well. The problem is that it was applied where there was no leak... Shame on me. Fortunately I didn't braze it HAHAHAHAHA

BTW, I guess the way to go is to pour the stuff inside, put the cover and shake like there is no tomorrow (of course with the petcock out and the hole closed. What about the cap? I guess one good idea is to cover the f*cking tank with a mile of transparent kitchen wrap, so there is no way to ruin the paintjob, but the cap is always an area to be careful about.

Raul

[Bob Wessner]

When I was cleaning and acid etching the inside of my tank, I cut a small swatch of a plastic sandwich bag to cover the fuel filler hole under the cap and then snapped the cap shut on top of this. It sealed the vent hole very effectively.

[Raul CB750K1]

Good idea Bob!!!! Thank you.

Raul

[dusterdude]

wow,way to go bob!!!

[jaannaktin]

 

A VERY THICK coat of automobile paste wax goes a long way, too. My tank was no prize, but I never got any acid on it with a thick layer of Turtle Wax in the way. It's nice to buff off afterwards, too, with the winter coming ...

Jaan

[Raul CB750K1]

Dave, I see what you mean. But this tank is not from a Honda. It is from a 4-year-old Suzuki GZ250 Marauder. The tank is just new, there is no way the paint is sealing the inside. Inside there is no visible rust of any kind. I'm still perplexed with this issue.


Raul

[Terry in Australia]

Have you found where it's leaking from yet Raul? I'd really be surprised if it was rust, more likely a manufacturing fault, or a stress fracture I'd reckon?

Tanks for Suzy GS1000's are pretty hard to find,(they were very susceptible to rust) so I've had to salvage a few, one I have developed a "split" underneath, I couldn't find it, so I "jury rigged" an air pump in the fuel filler and pumped some compressed air into it (not too much, or you'll be sorry!) and listened for the leak. I'm still unsure why it cracked, but I brazed it up and it's been fine ever since. Cheers, Terry.

[Raul CB750K1]

I believe the leak is in the rear seam, just below the seat. I put a folded paper napkin and this afternoon it was dam and oily. It seems like a liner application is in need. More than a manufacturing fault, I guess it has been a stress fracture. I would not mind to braze it just to make sure, but it would mean repainting and I don't want to do it now. Anyway, if there is water in the gas it would go to the lower end of the tank, so maybe it is just rust. I will use a inspection mirror to see the inside...


Raul

[Terry in Australia]

Fair one mate. My boss at the gas station where I used to work had a flexible tool that he could poke into a spark plug hole and look at the condition of the engine's piston and cylinder wall etc, I think it was some sort of optic fibre thingy, I reckon one of those would be good for checking out the inside of your tank, I wonder if you could hire one? Cheers, Terry.

[Raul CB750K1]

BUMP! It has been a while, but I wanted to give you feedback. I just picked up the tanks last weekend. I took them to the shop that will paint my CB350 resto. I have to say that I am VERY satisfied with the result. They told me they don't use Kreem anymore but an italian product called Tankerite -or something like that. 50 euros per tank, I also coated my new Sanglas tank, so 100 euros. I didn't want to run the risk to spoil tha paint, and these guys seems to know what they do.

Another thing that made me think they are pros is that they had a painted chassis of a V-Rod -after widening the rear fork- and some blasted parts -among them the pretty rear wheel- of a MV Agusta Brutale ready to paint gold. When somebody have the dough to buy those bikes don't take them to anybody.

Unfortunately, I will never know whether the tank has stopped leaking or not... I already bought a new body set for the bike and I'm using it, keeping the original parts for the future. Anyway, if it leaks, it is not their fault. They just covered the inside and my feeling is that the lining will cover the microscopic breakage at the lower weld.

Raul

[ElCheapo]

Raul dont let anyone fool you with some assumption that tank sealer becomes brittle. This is a statement made by people who have not used it. This stuff stays extremely elastic. If there is ever a problem with the liner in the future most can be reactivated with MEK. A few ounces of MEK, swish, swish, drain it off and you are ready for fuel within an hour in hot temperatures. Absolutely no type of fuel will reactivate the liner solution. My only experience is with kreem. It worked very well and have had no problems with the bike since. I have a buddy that uses red coat that uses the same process.

Whatever you choose, you need to be ready to go the distance and finsh the whole process in one swoop. ALWAYS use a good degreaser first (acid will NOT remove grease), Once you introduce the acid to clean the tank you have to keep moving. Drain it off ASAP RINSE with water and introduce the MEK PRONTO. Once the metal has been hit with acid and rinsed it will rust in about 45 seconds, so you MUST be ready to dump in the liner right after the MEK wash. When I do these I keep the liner bottle open during the whole process. Watch out on the MEK, as it is EXPLOSIVE to -500 degrees (in the old money). For God sake do not smoke when messing with thie stuff, unless you want a gas tank for a head.