change of a motorcycle rear shock bolt: what to use?

[Parduz]

Good morning, everyone. I own a burgman 650 and I want to change the rear shock absorbers.
Original shock absorbers are attached to the fork via a bolt m10, which reports a "7" molded on the headthe shock absorber is mounted in this way:therefore -from what I saw googlando- is subjected to cutting effort.

the new shock absorbers however have a threaded hole for m8, so - aside from the replacement of the silentblock- I have to change bolt.
Well, I'm not able to figure out which bolt to mount. I learned that there are various "classes" (8.8, 10.9, 12.9) but I am not able to understand what "equival" the original bolt ( credo that the "7" denotes the torque according to jis norms), as to take into account the reduction of the diameter.
I mean, what bolt should I mount to be sure?
(I'm not sure it's enough to say "take the most durable, on 12.9", I'd like to have a "reborn" answer, so I also learn )

 

[wert]

but widen the shock fork holes and hold the original screw? for how the fork is made, the bulk of the load bears it the section from half hole up, therefore, to the maximum risk the plasticization of the hole. instead switch to a lower diameter screw you would take much bigger risks.

 

[meccanicamg]

I agree with wert.
less diameter screw, load carrier.
if born with m10 must die with m10.
or look for a shock absorber identical to the original or holes and threads m10 the shock absorber.

 

[Parduz]

shock absorbers are in test. If they're okay, I'll make the changes, otherwise I have to make them. So at the moment I have to do with bolt m8.

and learn to understand the characteristics of the original Japanese and to make the "equivalences" with the classes iso - admitted that they are possible - it is interesting anyway.