I just replaced all 8 bolts -top and bottom. They are all 5M x .80 Pitch. I believe the top ones are 8mm long and the bottom ones are 12mm long. I took one of each in so I would get the closest match. I bought 4 5M lock washers for the bottom bolts because the originals had them.
Everthing was stainless steel. I got them all at this "Super" Ace about four miles from me. I call it "Super" because it is huge! I went to another Ace that was closer and smaller but they didn't have any stainless steel, metric, allen head bolts.
The allen head bolts look 20x better and are a lot easier to take on and off.
It was well worth it. I have been tuning my carburetor and it was so much easier. Now all I need to do is remove the air box, move the the battery farther to the rear, and fabricate a mount to keep the carb from jiggling too much. Once all that is done the carb will be easy as pie to get in and out and I won't need to remove the seat or nothing.
Once I get to above mentioned mod, I will post pics but until then you all can dream about it. I will also get pics of the allen head bolts shortly.
Ride Hard!