on tuning with the lsn/hsn, i have learned from experience and help on forums to no just rely on where the needles are. i turn them until it runs like it is supposed to. if you have two carbs from the factory and the taper of the needle is off a fraction those two carbs will tune a little different. sometimes if they are acting up it may be just a small leak somewhere, so be patient and check it out and you will get it.