Author Topic: Petrol Tank leak problem  (Read 471 times)

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Offline olasek18_18@o2.pl

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Petrol Tank leak problem
« on: January 20, 2023, 03:43:18 AM »
After painting, it turned out that the tank is leaking, there is a micro crack that I tried to seal with a special paint for tanks, unfortunately after about 5 days the fuel got through a small gap...
Do you have any proven ways to seal this? The method of tinning the tank from the outside seems to be the most reliable, but I'm afraid that at high temperature the sealing layer will peel off and I will lose my beautiful external varnish ... Are there ways to seal it with some preparation from the inside?

Offline BenelliSEI

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Re: Petrol Tank leak problem
« Reply #1 on: January 20, 2023, 05:37:06 AM »
I use Caswell products, available here in Canada. They are used for complete tank lining. Years ago my K7 had a tiny pin hole, in one rear corner. The bottom chrome trim strip had allowed water to collect there for many years....  the tank was so spotless inside, I did not want to line it and the paint finish was excellent, so didn’t want to damage.

I cleaned out the tank, as per the Caswell instructions. Mixed up a small portion of the liner chemicals and poured it down a funnel and tube to that corner. Keeping that corner low, swilled it around a bit and then stood it on end to dry. Basically a “local patch”, not visible from the filler neck. It’s still holding. Might be worth a try?

Offline olasek18_18@o2.pl

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Re: Petrol Tank leak problem
« Reply #2 on: January 20, 2023, 08:12:50 AM »
I was thinking exactly about this type of solution
 thank you!
If you can recommend any remedies available in Europe I will be very grateful

Offline BenelliSEI

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Re: Petrol Tank leak problem
« Reply #3 on: January 20, 2023, 08:38:38 AM »
I was thinking exactly about this type of solution
 thank you!
If you can recommend any remedies available in Europe I will be very grateful

I’m sure some of our members will join in soon. PeWe.... what do you suggest??

Offline xhevi

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Re: Petrol Tank leak problem
« Reply #4 on: January 20, 2023, 10:36:12 AM »
I use Caswell products, available here in Canada. They are used for complete tank lining. Years ago my K7 had a tiny pin hole, in one rear corner. The bottom chrome trim strip had allowed water to collect there for many years....  the tank was so spotless inside, I did not want to line it and the paint finish was excellent, so didn’t want to damage.

I cleaned out the tank, as per the Caswell instructions. Mixed up a small portion of the liner chemicals and poured it down a funnel and tube to that corner. Keeping that corner low, swilled it around a bit and then stood it on end to dry. Basically a “local patch”, not visible from the filler neck. It’s still holding. Might be worth a try?

+1 place the tank so the side with the pin hole is low.

I used POR15 sealer on a tank with not one but many pin holes along both sides.

First I placed tape on the outside "plugging" the pin holes so sealer had a chance to built up without running out from the pin holes.

Used the sealer per instructions but did not use the entire container and did not drain all of it. Afterwards I placed the tank such that it was leaning on one side to let the gravity built up more sealer on the low side.

Couple of weeks later I used a small quantity of the sealer that I had left over, but this time I placed the tank with the other seam lower.

It worked for me.

you can see the pinholes with a flashlight inside the tank and in a dark garage.



Offline PeWe

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Re: Petrol Tank leak problem
« Reply #5 on: January 20, 2023, 10:57:13 AM »
I think we have the popular tank lining kits.

I bought a "Restom Superkit" 10 years ago that I have not used.
I read about it on a Swedish site where they used it on an old bike. I think it is french.

I searched and found several.
https://www.restom.net/fr/21-374-restomasuperkit.html#/179-contenance_de_reservoir-15l_a_25l

https://www.alpdiffusion.com/peintures-et-traitements/traitements-reservoirs/restom-superkit-reservoir-oxyde-15-a-25-litres-degraissant.html

I guess I ordered mine locally in Sweden. 15-25l kit
https://www.kinn.com/product.html/tanktatning

« Last Edit: January 20, 2023, 11:05:32 AM by PeWe »
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline Tim2005

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Re: Petrol Tank leak problem
« Reply #6 on: January 20, 2023, 11:32:15 AM »
I've used POR15 sealer for a pinhole successfully too. I prepped it with oxalic acid rather than their own stuff, also although the instructions said it was ok to use the tank in a short time I left it for several weeks until the sealer fumes had cleared. This was about 10 years ago & it is still good.