yep youre probably not using a powerful enough motor for 210 kg of weaponry, try a dual perm
That's the best non-cheatbot motor you can get. It might be the way you're using it on the bot that's causing a downfall - I know for sure I can take Grog very easily using a DSL bar on a dual perm with 2 70kg hammers. Feel free to upload a pic of it and put it here or start a showcase :P