vinniebrown013

Hi guys, I have recently purchased my first Yamaha and I love it. The problem I have is that when I got it I gave it a good service, changed the gearbox oil ect.. I also drained the existing 2 stroke oil and replaced it with good quality fully synsethic oil and since then its been running really badly. When it gets to about 7000 rpm it splutters and mutters and I have to ease off the throttle and gently try to accelerate again which helps a bit but its still not right. Is it the 2 stroke oil coz thats the only thing I have changed??? I am very confused with it. What 2 stroke oil would you recommend? Also I want to get a better performance exhaust on it, can any one recommend the best/ cost effective exhaust for this bike. Finally I have heard about BOYESENPOWER REEDS being very good, does anyone know any info re these reeds and is it worth doing. As you can guess I am a novice with bikes and any help you can give would be most appreciated.