Motorcycle Repair: 1972 CL175 gas tank rust, honda cl175, polymer coating

Question

Greasy engine block Hello,
I'm working on restoring a 1972 Honda CL175 K6. Only has 2080 miles on it, all original. The gas tank has a lite coating of rust in the tank. I've found several recipes for addressing this issue. What would you recomend ?  Also the engine casing/ cooling fins are coated in a dirt/lite greasy mix (see pic)... Any suggestion on products that are heads above the others in removing this kind of mess? And how well do gaskets, seals, etc. hold up over time once a bike has not been started for many years. The bike was stored in doors most of it's life.

Answer
James, if the tank isn't rusted through you can clean it out with phosporic acid.  It desolves rust and leaves behind a very good protective coating.  There are also other products that will seal up the rust with a polymer coating.  If the rust isn't more than light film, I'd just clean it out well and leave it.  Put a couple of filters in the fuel lines to keep the chunks out of the jets.  If you are going to ride the bike, it will eventually flush itself out.  

There isn't any product I know of that will desolve the aluminum oxide.  If it's grease build up, I've been told oven cleaner will cut the backed on grime.  I've never tried it myself.  Sorry, can't be of more help.