do you think any Hw could defeat lyoto machida?

Depends, at 205, plenty, Lyoto's really strong, but people like Carwin, Mir and Lesnar have like 80 to 100lbs on him.

Back when Lyoto was 230?

Dunno, Cro Cop mullered people at 220, so it's conceivable that Lyoto could go far.

Machida is one of those fighters that is really a catchweight guy, he would benefit from an extra 20 or so pounds, he'd benefit from it striking wise, but he's just to small to be a HW.

Height and weight difference is something that will give Machida hard to deal with them, besides, there are lots of heavyweight fighters that are good on their field according to their individual skills.

It's hard for Lyoto Machida to handle them like Dos Santos, Cain, Lesnar, Mir and Carwin.

......................................

I don't think he would do well. One of the main reason he is so good at 205 is his speed. There are plenty of HW fighters that could match his speed if he added 20 lbs. I think the sheer size of the HW fighters would be to much should it go to the ground.

I think he could do really well if he dropped down to 185. If Anderson Silva ever moved up to 205 and took the title... I really think Machida would drop. He would be lighting quick at 185.