Tank restoration?

**Mort** · 21st April 2015, 10:15

I have a mate restoring a couple of 1962 Honda CB92 race bikes. He has found the inside of the fuel tanks to be corroded. Does anyone know a way this can be dealt with. Is there anyone in NZ who can deal with it ? Any ideas also welcome...

**Trade_nancy** · 21st April 2015, 10:35

If it is surface rust - I dealt to my 72 CB750 tank by using electrolysis. Fill tank with SALTY water; connect a metal rod to plastic insulated cap over the filler so the metal hangs in the solution but does not touch the tank; fit positive of your 12v battery charger or similar power source to it and the neg lead to earth on the tank metal. Turn on power to charger. Leave for a day. It will bubble and froth up brown rust. So put the whole deal in a place you don't mind turning brown....like on a plastic tarp...End result is rust dealt with and a pitted metal interior..which must be protected within minutes before it flashes with rust again. I sprayed it with wd40. You can line the tank with something like POR-15 or another brand of fuel tank lining later.

**Voltaire** · 21st April 2015, 11:13

Never tried the method above but sounds interesting.
I've done a few thanks with light rust.
Por 15 marine clean or metal ready ( not sure which)
I used a handful of small nuts to swirl around the mix, its gets warm.
Wash out, dry overnight
Then POR 15 tank seal, you don't need a lot so get small tin.
Swirl that around, leave to dry with an air line going thru it.
Did my BMW race bike tank and it was pretty rusty.

**Erelyes** · 21st April 2015, 12:01

This looked like a good method to me. Not tried it.

**Grumph** · 21st April 2015, 14:08

Those early Honda tanks are a bugger to get right. All the paint and any plating has to come off and then you can see how bad the pinholing is - and it will be pinholed...
In the past I've had to weld in patch panels which is often not easy. The sealants can only cover so much, nothing worse than a nicely restored race bike that develops a leaky tank which then has to be done again.

**Mort** · 21st April 2015, 15:47

Nice going guys - I will pass this info on and see how we get on... Cheers.

**Akzle** · 21st April 2015, 20:00

electrolysis is the fucking shiz.

never done a fuel tank, though.

DO NOT get the leads the wrong way around. you've been told.

**neels** · 21st April 2015, 20:29

Have done the POR15 thing on a gunked up rusty old tank worked mint. You can buy a complete kit that has the cleaners and sealant included.

**AllanC** · 22nd April 2015, 15:53

Damn, there's some clever people around!

**jellywrestler** · 22nd April 2015, 16:42

Originally Posted by neels

Have done the POR15 thing on a gunked up rusty old tank worked mint. You can buy a complete kit that has the cleaners and sealant included.

that rust has been happening for over 40 years, it vastly depends on the amount of the rust to the answer, por15 isn't the magical cure all.

**98tls** · 22nd April 2015, 17:59

Originally Posted by jellywrestler

that rust has been happening for over 40 years, it vastly depends on the amount of the rust to the answer, por15 isn't the magical cure all.

Spot on,i started out with one pin hole so blew the thing out which revealed much worse,soldered it up and was good to go....

**caseye** · 22nd April 2015, 19:35

About a thousand years ago ol Volty por'd my coal burners main tank.
It wasn't in good nick then.
Now it's been about 6-7 years and no sign that the rust will ever come back.
It works, when used in the right cases.

**Voltaire** · 22nd April 2015, 20:26

Originally Posted by caseye

About a thousand years ago ol Volty por'd my coal burners main tank.
It wasn't in good nick then.
Now it's been about 6-7 years and no sign that the rust will ever come back.
It works, when used in the right cases.

That's good as its out of warranty

I did my 900ss as it had rust in the lower section, common on these.
Followed the process and found it had a couple of pinholes letting fuel out.
Took it all apart and did it again and perfect.

**98tls** · 22nd April 2015, 20:36

Originally Posted by Voltaire

That's good as its out of warranty

I did my 900ss as it had rust in the lower section, common on these.
Followed the process and found it had a couple of pinholes letting fuel out.
Took it all apart and did it again and perfect.

SS as in bevel or later V?The tank i posted pics of was my oldish TLS,blew me away that it was that bad really,the 74 motorsport in the sheds tank has no problem whatsoever.

**Voltaire** · 22nd April 2015, 21:36

Originally Posted by 98tls

SS as in bevel or later V?The tank i posted pics of was my oldish TLS,blew me away that it was that bad really,the 74 motorsport in the sheds tank has no problem whatsoever.

Rubber band SS, water tends to collect in the lower areas. Probably worse in Jap imports as they appear to sit around a lot prior to ending up here.