O/T Any scooter (tuning) experts out there?

[Martin S.]

My lads Yamaha Aerox 50 is fitted with a sports exhaust and lightweight rollers. Lately he’s been having problems with picking up especially on hills where it would rev but go nowhere.

 

So yesterday I fitted a new drive belt and 5.5g rollers as I was advised by the bike shop that was the correct weight for the exhaust fitted. The rollers that came off had flats worn on then and weighed 4.1g.

 

Anyway out for a test run and pick up was smoother but it would only go to about ½ revs which I assumed was due to the rollers being too heavy . So put the old 4g rollers back on and it seemed fine again at first but then started playing up again. He’s not very good at describing faults but I think it wouldn’t rev again. I’ve ordered a fresh set of 4.1g rollers as I’m wondering if the flats on the old ones are making the sliding pulley stick.

 

Any ideas?.......and how do those auto clutches work, why doesn't the gearing go to max as soon as you rev the thing and the rollers get forced outwards