Hello I have had mopeds before and thought I get a cheap moped for work again but I wanna do some engine upgrades with out putting a big bore kit on it is there any upgrades people reccommend what will make it better top end
You should replace the stock variator with a Malossi or a Polini one with some lighter rollers. This will significantly improve the take-off from a standing start as well as add a bit more top end. The roller ramps on the upgrade units are a bit more aggressive than the stock one and these upgraded variators allow the drive belt to ride a little higher, giving you more top end. A tuned pipe, such as a Leo Vince TT or ZX will give you improved performance, although you will need to up-jet the carburettor slightly, or replace it with a 100c version carb. Get the inlet manifold and reeds if you change the carb for the 100cc one, as they are much less restrictive, compared to the 50cc one. The fittings for the 100cc carb one (hose clips) are also different then the 50cc one (bolts), although the new setup should still connect to the existing air box. Also, get a decent upgrade foam air filter element for the air box and this will improve the engine's breathing. Finally, get a clutch spring kit that will allow you to adjust the point at which the clutch kicks in. It won't add any more top end, but it will improve the take-off still further. This little lot should see you go from 35MPH to more like 45-50 MPH and this will make it a much easier ride in traffic, particularly on A roads.
The Viva uses 9 gram rollers as standard - I would try 8 to 8.5 and see how that changes things. it also has a restriction washer in the variator that you can take out for now for a small free speed increase. There will also be a restriction washer in the exhaust throat or a resonator tube on the side of the exhaust, depending on how old the bike is. Dremel the restrictor out of the exhaust inlet, upjet the carb by adding four to the current jet size and if your bike is a later model and has the exhaust with a resonator tube, this resonator tube needs removing and the hole in the exhaust left behind welding up. Some people cut the resonator tube short and hammer the end flat to the exhaust but welding is a better way to do it.
As long as you use three of each and alternate them to keep it in balance, then yes, you can mix and match lighter and heavier rollers, to get in-between weights. Just be aware that the heavier rollers might wear more, due to having to take the extra load before the others kick in.
