View Full Version : 1926 J - Cleaning the Tanks, Adding Accesories

07-17-2016, 08:25 AM
Recently acquired a '26 J that was in static display for 20 or so years. The previous owner ran it through the gears, so I know it runs and shifts, but he bypassed the fuel tanks as they need a good cleaning.
Assuming they are original sheet metal, what is the best way to clean the inside from rust and varnish? I did a caswell job to my '59 BSA, but I'm thinking I need to be more careful with a 90 year old bike.
I'd also like to install a side stand and a hand clutch lever.
Thanks in advance, especially to the guys who have already been so helpful (Joe, Mark, Dan and Mudfish), Pete

07-17-2016, 10:41 AM
Hello Pete, the tanks on my 20F are only made of 22 gauge steel so I would suggest that you leak test them first. Dont use water to leak test them because hydrocarbons have a lower surface tension than water so a tank that holds water may not hold petrol. I suggest an air pressure test at between 2.5 and 4 psi.

For cleaning an old tank I put some small nuts, ball bearings etc in the tank then add a liquid such as WD40, paraffin etc then seal it up and then wrap the tank in some protection such as bubble-wrap. Then I wedge it with cardboard into a small electric cement mixer that I have and leave it going for several hours. You could use water and a small amount of soap instead of paraffin if you think that you might need to weld or solder the tank later to ensure that there is no vapour.

However there are some points of caution when doing this. If the tank is suspected of being very thin (which a J tank could well be) then the abrasive action of cleaning it like this might mean that a tank that didnt leak before cleaning might leak afterwards.

Also, my 1920 tanks have a built in brass mesh filter. If your 1926 ones are similar then you risk holing the brass if you use anything but very small ball bearings or nuts as an abrasive.

There are also some cleaners specifically designed for tanks on the market. For example the POR15 tank liner kit has a cleaner that it comes with that I used on my 1939 5T. It seemed very good although I did use it after I had cleaned the tank using my cement mixer method above so I cant comment on the cleaner on an old and dirty tank.

I am sue some other people will be along with some other options and ideas, then you can take your choice and see how it goes.


07-24-2016, 06:51 AM
I had good success with screws and acetone but the baffles slow the process. As said earlier you run the risk of making more leaks if thin though. From my experience vinegar is too aggressive if you are considering that option. Good luck.

07-24-2016, 12:52 PM
This question is timely. Today I cleaned the left hand petrol/oil tank for my 20F. It pressure tested OK before I cleaned it but after 5 hours being agitated with a mixture of engine cleaner, nuts and ball bearings I had a clean tank but one with a small leak on a seam. It was in the oil side of the tank so it must have been gummed up with old oil before.

Luckily it was a simple fix to just re-solder the offending area.


11-14-2016, 09:55 AM
Side stands are available on the net and generally fit on the front footboard bar, makes life a lot easier.
Hand clutch is a different ball game as you still need a hand to change gear with the clutch engaged.
Am assuming no front brake so that will increase your ground contact especially on hills if you change to hand lever.
Beware of the flack you will get from the traditionalists !

I used 10mm pea shingle to clean my tanks.
If they leak after this then they needed repair anyway


Chris (England)