Originally Posted by snoebel
HSN needle is very easy. Just tune for max speed, en make sure that even on top speed you still see smoke (more then with a 2 stroke). If you go lower you will find that the engine rev's higher, but get's way to hot and then looses power very fast.
What temps are you seeing? Unless it's over 250F (temp the cylinder, not the head), it might just be warming up.
When race tuning with the 2 needle carb, it'll change tune once it reaches operating temperature, usually above 200F. Always tune after warming it up. When tuned properly, it'll act lean when it's cold: It'll idle fast and lean-bog when you give it full-throttle (or flame out if you hold it open too long). After warmup, it'll idle down nicely, respond crisply, and run clean and strong on top. Also, if you're using the low-smoke fuel, it won't smoke much at all except at idle.