I have been removing rust from all kinds of engine parts using a 5
gallon bucket, a 1 amp battery charger (2 amp might be faster), a coat
hanger, a stainless steel spoon or tongs (I tried rebar at first but it
required cleaning too often), some small clamps, some water and some
washing soda.  Pretty amazing how well this works.  Instead of writing
all about it here, just do a browser search and you will find out how to
do it.  I let things bubble away for 24-48 hrs...or longer.  I use a
wire wheel to clean the parts afterwards.  Works great for the muffler
support rods, and metal coolant pipes in the engine compartment. Ah
science is amazing...  Just ask if you have any questions on my setup.
Oh, BTW, a by-product of the reaction is hydrogen so watch for sparks
and keep it in a well ventilated place. ;o)

 

Pascal

'84 Westy