The best reed valve for Yamaha RX-Z is from the brand Boyesen. There are two choices to choose from; carbon fibre or steel. It is priced at RM100.

Using this reed valve will enable your RX-Z to rev higher than normal, and this is good to get better top-end speed.

Comments?

How to get a good speed and good pickup for RX-Z? For now, my top speed is just 140km/h and looking forward to make my RX-Z top speed reaching the ‘km/h’ label (about 220km/h). Is it possible? What other modification do I need to do? Also, the top RPM is just 9000+. I have looked at one of the RX-Z reaching far beyond the 12000+ RPM. How do they do it? Comment if you know how!