Really bad idea...I am surprised it sheared the grade 8...I would go back to grade 5 and find out what the real problem is...I would rather the bolts break that the cases to your engine...but that's just me.

My guess is the reason they are breaking is the rear swingarm mounts and or the top mount are shot .

 

That's a four year old post. Problem was fixed long ago.

 

A good old thread that even applies to first generation twin cam frames. All the replies are worth looking at. Perhaps at 153K the top mount is worn. Interesting.