Racerone is correct, it's time to start gathering some basic info to find the real problem. I always suggest doing all the free, easy things first then move on from there.
1) Use an inline spark tester. Remove all 6 plugs and test each lead 1 by 1 and verify each coil can jump a 7/16" gap while cranking.
2) Measure compression values on all 6 cylinders. You should see 100PSI on each and no more than 10% variation.
3) Confirm integrity of all your fuel lines. Make sure the tank vents are open and there are no air leaks in any hose or connection
4) Verify your primer bulb is good and the check valve is working.
5) Look for leaks around the carb fuel chambers. Any weeping around the gasket is an air leak
6) Check around your fuel pump and make sure there are no leaks at the fittings or cracks in the pump body
7) Look around the gasket on the VST and check for leaks
8) Look at the sides of the float chambers for a small BB pressed inside one of the holes. These are notorious for leaking as the plastic ages.
Do you still have the factory OMS fuel pump? Does the engine seem to smoke excessively? If yes, it's possible you have a bad diaphragm on teh fuel side which will cause decreased fuel flow and excess oil delivery and bogging at high throttle settings. My '96 Intruder 150 had similar symptoms 2 years ago and I decided to install a new OMS pump which along with replacing leaking fuel chambers gave me an engine that runs just as well as it did when new. There are kits to rebuild the fuel side only, but I chose to do a full replacement.
KJ