Hi, I have just bought an aerox with either a 70cc big bore or a 77cc not exactly sure, it was fitted by a garage and is still being run in by me so it does have a higher ratio of 2 stroke oil. My mates 50cc aerox will do 45mph however mine struggles to reach 40mph at the moment. It has been de-restricted and has a leo vinci tt exhaust. Any suggestions as to why..... it could just eb the higher ratio of 2 stroke oil.

Thanks

possibly, what other mods went with the over bore?

bigger carb and/or rejet, updated variator and clutch?

I'm gettting the list of what else has been upgraded but the things i can remember are the exhaust, carb re-jet and polini rollers, there are a few more bits but i haven't had the list through yet.

Thanks for your quick reply.

Would there be any other things that could have effected the performance?

if the bike can rev, I suspect that the tranny is not matched to the power charactistics.

I assume you checked the spark plug colour, it should be light brown indicating the correct mixture.