Replacing exhaust and centrifugal rollers yesterday on Grandsons bike. Fitted all new centrifugal parts and something was not quite right and a mechanical rubbing so all out again and replaced the original parts but used the 6 new rollers and now that problem solved. These rollers have different weights so i used 6 gram ones which keep revs lower at take off. Then the stainless sports exhaust which needed some new brackets i made from steel flat bar.
The exhaust is a little louder so pedestrians should hear it coming.
He has ridden a few hundred miles in about 3 weeks and now commutes 12 miles to Exeter every day so its a reliable bike for 13 years old with 24,000 kilometres on it so far. One of the best sounding engines of all the ones i have been mending for Grandchildren and this one has not had all the panelwork smashed up.
It will do 45 mph on the flat at the moment so no plans to add an overbored cylinder as it may already have one. You can get 100cc kits at £100 but that cannot increase speed as gearing does not change. Just means it does not slow down on hills so making it safer .
This one is branded KYMCO but all of these 4 stroke scoots use a common engine so been fixing 4 brands of these which all use the same parts