Now that we fixed your language issue.
The answer is maybe or maybe not. Maybe your brother is just a better rider or maybe he's an average rider and your just slower than snot on a flag pole in Fargo ND on January 2nd. Maybe your old bike was holding you back but the only way to find out will be to do it and find out. How do I know this? My son has a CR85 and a hot rodded XR80 (95cc, cam, headwork....) and I can beat him on either bike even though I weigh 210. It won't be that way for long as he gets more familiar with the CR85 he'll have the edge but right now that's what would happen. Put RC on a 85 and me on a CR500AF and RC will spank me. It's not always about the bike, well actually almost never is it about the bike, it's usually skill and some luck.