Engine cradle bolts

[phil on a fazer]

right....I'll try and explain this the best i can.

I have yam crash bungs that attach via two bolts to the frame. the bolts go through the frame, through the engine cradle and are secured at the back by nuts/washers. If you stand at the side of the bike and look at the bungs the top bolt is slightly thicker than the lower one (you can only tell that by looking from the inside though)

In the Haynes manual under torque settings it says....

Frame cross-piece-to-cradle bolts   33Nm
Frame cross-peice-to-engine bolts  55Nm
Frame cradle-to main frame bolts    24Nm

so from the above which torque setting applies to the two bolts I'm talking about?

Answers on a postcard. 

Cheers

[cable tie]

Hi.. the bolts that go thro the crash bung are:
 
top bolt m10 = 55nm  (the yam service manual states 33nm for this bolt as well but the link below states 55nm)
bottom m8 = 33nm
 
 
the bolt that goes thro the cradle and thro engine block is m10 and should be = 55nm.
 
This link may help in the future    http://www.cartestsoftware.com/fz1/index.html
 
Dave     
 

 
 

[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.

[JKay]

Excellent observations on that link Phil, Duralac is the dogs for isolating aluminium and other alloys from the steel bolts ect