with more power the gear can be broken off?

[Fulgor72]

it is not that with these motors the gear can be broken off?
I have found a Zenoah 26cc ported with 4,5HP with the standar muffler!

 

[TheFgMan01]

I haven't had a problem on my Fg H2.. and im running a 29cc with Dominator pipe.. my spur is plastic the rest are steal. but my plastic spur hold up to the abuse of the 29cc