Engine cradle bolts

[phil on a fazer]

arrr...yes...i always forget about that website!! Even though when i first got my bike (4 years ago) i seemed to be forever reading that site.

an interesting bit from the site though about fasteners:

From Wally Hartung, an aluminum industry metallurgist, warning about using a copper-based anti-sieze. In a galvanic corrosion situation involving aluminum and steel, we're not worried about the steel. The aluminum is the sacrificial metal and will corrode preferentially, protecting the steel. The presence of water is absolutely necessary for the reaction to occur. Plated steel bolts (plated with either cadmium or zinc) will afford some protection to the aluminum, but only as long as the plating lasts. It's being used up as it sacrifices itself to protect the aluminum. As soon as the plating is used up, the sacrifice of the aluminum parts to the steel will begin. The white powdery coating on one of the bolts looks a lot like aluminum oxide. Guess what part is really getting eaten up. That's right, the aluminum case. Now if you want to really see aluminum go to pieces, get copper involved. Copper eats up aluminum in a situation of dissimilar metals with water involved. Copper based anti-seize should NEVER be used in contact with, or where it can get in contact with aluminum. Use the aluminum powder anti-seize, always. My knee-jerk reaction recommendation to fix this corrosion problem would be to:  

• Clean up the existing corrosion. If the steel bolt hasn't been significantly corroded (just light surface corrosion) clean it up and reuse it. If there is any question as to a reduction of the cross area of the bolt due to corrosion, replace it with the proper factory bolt.
  
• Spray the bolt with WD-40 or other anti-corrosive that is compatible with the rubber pieces. (I went out to the garage to look at the mounts and noticed there is a rubber piece in the joint. Like I said, I just got the bike. Vibration isolation part, or seal to exclude water, or both?)
  
• If you've got copper anti-seize where it can get in contact with the aluminum cases, clean it out of there completely.
  
• Use a little RTV to seal the assembly. The basic idea is to get rid of the water incursions into the bolted joint. Without the water, no corrosion.
  
• Blue Loctite on the threads, not copper anything.
  

This is why I never use a pressure washer on a motorcycle, they'll force water into all kinds of places it's not supposed to be. Also, never use a plain steel or brass(copper) wire brush on aluminum during the corrosion cleanup. Always a stainless steel wire brush. Steel or copper based wire brushes will leave small particles and lead to pitting of the aluminum. 304 stainless fasteners are fine with in contact with aluminum. There is a surface passivation involving the chrome oxides that form on the stainless that precludes the formation of a galvanic cell under most conditions. Wally advises that by just looking at a couple of photos of one component of the problem he really can't offer a professional opinion from such limited information. There may be other factors involved, but the basic premises of keeping the water out and not using copper are sound.