Re: jet size?
To answer your question most come with a .7mm jet. But as Max pointed out your loss of power at top end is typically due to a too large of jet and it running rich, or 4 stroking as it is sometimes called. I also agree your first course of action would be to adjust the needle on the carb slide. If you remove the cap on the carb and pull the carb slide out you will see a pin that sticks down the carb. On top of the pin are grooves that an e-ring clips on. By moving this e-clip up or down you can alter your mixture. Be careful when disassembling and what the order things are placed. If you move the e-clip up one notch it will lower the needle allowing less fuel to enter the intake and lean out your mixture. The needle has most effect on the low and mid range mixture and doesn't do much for top end but it will help a little. We recently sourced some jets and will start offering them sometime next week.