i was wondering how to make my razz go over 40
It can be done but there are no performance parts made for the razz.
Copy paste from my old post:
This Yamaha motor is unique in that it uses a centrifugal clutch and single speed chain drive to the rear gearbox arrangement. Most modern 50cc scooters use the belt drive automatic transmission. As there are no parts available specifically for this model, parts must be adapted from other Yamaha machines.
In order to substantially increase top speed the engine must rev harder and produce more power. There are no gear kits available to change the overall gearing, although fitting of a larger section rear tyre to increase the overall diameter of the wheel will give more speed for a given engine speed.
The easiest performance increase comes from using a 70cc Yamaha BWS/Zuma cylinder which fits the crankcase but requires the reed and inlet manifold from the BWS/Zuma as well. The standard air box can be used but the standard carb will need rejetting. Fitting a larger 17mm carb will give a further performance increase.
The only troublesome point comes with the exhaust. The BWS/Zuma exhaust flange studs are in a different position to the standard cylinder. The standard exhaust could be used and the flange cut and rewelded to the suit the BWS/Zuma cylinder, or a BWS/Zuma exhaust could be used.
Unfortunately, using a BWS exhaust will give problems with clearance to the frame, so it needs altering to fit the machine. To further complicate matters performance exhausts come in very different types, and as the Razz is not available in the UK for us to try the different systems on, I cannot give guidance on what modifications would be necessary to make different exhaust types fit.
It is possible to achieve 50mph from the Razz using the higher RPM BWS/Zuma exhaust with the 70cc cylinder kit, but modifications need to be made to the clutch shoes so that the centrifugal clutches bite at a higher RPM, giving improved acceleration from a standing start to 10mph.
The other alternative is to use an exhaust that has more mid-range power. This includes the Giannelli Sport Cee exhaust, which gives good power all through the rev range, or the LeoVinci SP3 or the Technigas exhausts. These would probably work without having to adjust the clutch shoes, as bottom end power is much improved.
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