I work on bikes like yours all the time for the bike exchange. Unless you have a painter custom color some paint for you you will not be able to blend the rusted areas in to your existing paint. When you have bubbling , crusted rust spots the best thing to do is scrape the rust off with a blade. A single edged razor blade , often bought is packs of ten or more, is scraped sideways over the rust and will take all the scale off. wire brushing will remove loose rust but will just burnish the scale. After scraping as much rust off as you can with the blade, take a small brush or q tip and heavily coat the areas with naval jelly. Use rubber gloves . Don't worry to much if you get some on your skin, just wash off immediately with water. Let the naval jelly sit for 15 or 20 minutes then put in the shower and rinse. This should take care of the rust. If necessary repeat the scrapping then sanding then naval jelly .



Sometimes when I have a frame with lots of small nicks and surface rust in/ on the paint I will brush naval jelly on the entire frame. This can do wonders. after treating all the rust I would use white polishing compound and rub out the whole frame with it. This will get rid of lots of minor blemishes that have been ground into the paint. Now you can slot prime the rust spots with a self etching primer and then carefully paint the spots with a color of your choosing. With dark colors, black is usually less noticeable than trying to match the original color. finally, if you can set the frame up out doors or in a garage, set up a table or hang the bike from the ceiling and spray it with rustolium clear Automotive enamel. You will be surprised how good it will look. If you are worried about doing this indoors, Years ago a room mate painted an entire car in our living room ( body panels removed from old MGA) with 20 spray cans. covering the floor and walls with plastic. first. Throw down a 7 x 11 ft tarp and you could spray the bike without anyone noticing . you are going to be using less than one spray can of clear . Any other color could lead to disaster so just spray the clear.