You will need to give it some throttle to take off, it's not like the 4 strokes where you can practically just launch it with just clutch only.
When the engine is cold, I always start it with the choke on. When it's warm, I usually don't.
The topic of mixing oil brands is still under debate by the experts on this site.
I pump Mobil 8000 or BP Ultimate (98RON fuel) coz that's the best we can get in Aus. I try to avoid the Shell Optimax (Shell's 98RON fuel). Alot of people don't recommend them for carbied 250's.
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Jerry Lai
NSR250 [MC21SP]