My RT2 was stuttering at about 50 mph and would ping when I came off the throttle. I live in the UK at sea level and the climate here is mostly damp and cold. It's all standard and the carb main jet was 230 and pilot jet is 45. I have now changed the main jet for 270 and it's running a lot better, pinging has also gone.

Do I need to change the pilot jet, would this make any improvement ?

I have # 250 main and # 45 pilot jets in my RT3 and RT1B regular riders. They do run smoother with no ping. I have to replace the sparkplugs a little more often but that's OK.

Good to know thanks. Do you think the 270 main jet is too much then. How come you have to change the plug ? I haven't altered the needle setting so would this help ? I had the bike converted to the vape 12v electronic ignition system and is a lot more reliable now.

I would leave the 270 in it if it runs good. My needle clip is in the middle position. The plugs tend to foul a little more with the richer mixture.