250 Monza: rust in tank

[cooperplace]

the bike that I'm putting back together hasn't been ridden in years. A glance into the tank shows it's not too bad but there's some patches of rust. I'm thinking of using rust converter then applying a sealant of some sort. Back in the day, ie, 35 yrs ago, I used Kreem in my old 450 and it worked fine, but now I read that additives in modern fuels disagree with this.
Any thoughts? Wise words from the experienced would be much appreciated.

[john jupiter]

I have used evaporust for light rust with really good results. a sash chain or some wood screws also work well to if you have larger flakes. I have been lucky and have not had anything other than minor surface rust so I didn't use a sealer and keep gas in the tanks and ride them. I have heard good things about POR 15 tank sealer if that is the route you are looking to go.

[Jordan]

A handful of plasterboard screws and some kero in the sealed tank, shaken until your arms are about to fall off, will loosen off heavy rust.
A labour saving method is to use a cement mixer or similar. Wrap old blankets and stuff it in with enough padding to protect the tank, and run it for a while.

[JimF]

I swear to God this is true...

A friend of mine put the screws in his Norton tank to scrape the rust off, but being too lazy to shake the tank for an hour or more he somehow mounted it to his grill's electric rotisserie and let that spin the tanks for hours on end. It worked.


Jim

[cooperplace]

excellent, thank you. I will borrow my brother's cement mixer.

Any thoughts re whether I should apply some sealant? There are no holes, and it looks pretty good inside.

[StewartD]

The advantage of the concrete mixer is you can give the tank treatment in a few different orientations. On the rotisserie, if mounted as if rotisserie shaft is the frame top tube, then you will not get very effective cleaning of the front and back of the tank. The front and back will not be effectively impacted by the abrasive. Also, only one side of the tank's frame tube tunnel will be masked unless rotation is reversed, or the tank remounted, end for end. The concrete mixer will allow the tank to be mounted in all sorts of orientations, so that no masking occurs, and that direction of rotation, which will favour some areas of the tank, can be effectively countered. Be careful to pack around the tank tightly.

Cheers,

Stewart D