Pete,

First set your high speed needle to about 4 turns out then you can set your low speed needle. For the low speed needle, the manual says to have the carb barrel opened about the thickness of a sewing needle. I assumed this to be about .025". Connect a fuel line to the carb and blow into it. You'll want to close the low needle just until the airflow stops. Start the engine and it will be running really rough. Leave the glow igniter on it and open the throttle until you have it between a third and half open and then remove your glow source. Let the engine warm up a little. Next pinch the fuel feed line and see if the rpm increases. Do not pinch and hold, just a momemntary pinch and release. If the rpm does increase close the high speed needle about an 1/8th turn and let the engine run at least 30 seconds like this, then pinch again. Keep doing this until you no longer notice an increase in rpm. Once you pinch and release and do not notice any rpm increase you are at the max lean setting. (Remeber, this is with the carb opened about half, not full throttle). This setting is the leanest you should go with the needle so make note of how many turns out it is when you shut the engine down. I opened my needle about a 1/4 turn past (rich) the max lean setting. I then brought the idle down and leaned the low speed needle about 1/16th of a turn. Before you start this whole process, make sure your spray bar is pointed straight down. You can see this by looking through the bottom of the carb with the barrel wide open and you'll see a cat's eye cut in the bar. After your low and high speed needle are set you can rotate this bar by loosening the screws on the left side of the carb near the fuel inlet and this will allow you to adjust your mid-range transition. I did by a perry carb and it runs well, but i decided to give the factory carb another go after having many problems with it. Turned out that when I read and FOLLOWED the directions, the factory carb tuned right in with a real smooth transition. Good luck (PS Make sure you have the right fuel for a big tigre. 20% oil will make it run like crap. I am currently running 5% nitro and 10% oil, with an OS Four Stroke plug.)