Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
I have cleaned the tank on my RD350 with amazing results.Wash the tank out with water then get a small tub of Bicarbonate of soda from the supermarket. Mix it with water then fill the tank to the brim, I use half the tub with full tank of water.Connect a DC power supply, battery charger or whatever. Negative to the tank, and the Positive to a steel bar (I used an old Allen key) and put it in the filler neck but don't let it touch the tank.Turn power on and watch it fizz, keep topping the water up and every now and then clean the steel bar. It will take a good few hours. Also swirl the tank around to removed any trapped pockets of air.Best to do it outside as the bubbles produced are Hydrogen I don't have a before pic but it was so bad I was on the lookout for a new tank.This is a fairly slow process, it probably took 12 hours or so.
Why can't you have rusty petrol tank shot or bead blasted?
QuoteWhy can't you have rusty petrol tank shot or bead blasted?You can - nothing stopping you. If you mean why isn't it a good idea that's different - and I can tell you that having had the outside of a tank sandblasted, I'd be very wary of trying to do the insides the same way. Long story, but I'd decided to get a tank powdercoated (yeah, long story . . . don't ask) and since the frame was going the same way, I just added the tank to the set of bits to get blasted. Saw it halfway through the process and it looked absolutely fine; paint free and no rust either inside or outside. Powdercoating completed and it looked great. Things started to go sideways when I put fuel in it . . . . . . the grit was sharp enough to put two near microscopic holes in the underside. Poking around confirmed there was no rot; the grit had simply found a couple of very slightly weak spots around weld seams and blown though. Fuel and powdercoat really don't mix, and so I ended up needing to get the tank done again. And then the rebuilt fuel tap leaked . . . Suffice it to say that unless you're going to use a very soft media type or do something like vapour blasting, it's really not worth risking the cost of a paintjob simply to save a couple of hours work. At the same time, the insides of tanks can incorporate some very odd shapes that aren't easy to blindly work around. The tank I had done is from the mid-60's and has such a high middle section where it straddles the frame that it needs a connector hose to get fuel from one side to the other (hence the number of weld seams). Working around that sort of thing would be a nightmare - and as others have pointed out, getting the media and the ultrafine dust it generates out when you're done would be more trouble than it's worth. You really don't want any of that getting into the engine . . .