Carb Tuning Help - Have symptoms need a cure

[DoubleL3]

So I have a 81 KZ550 the exhaust is pretty much a straight thru 4-2 w/o a crossover, and i now have pods because the old filter was shit.

Now to the symptoms:
- i get some pretty decent backfire while closed throttle decelerating above about 5500 rpms
- if you rapidly open the throttle to full when the motor is under 3000 rpms it will kill the motor
- power seems decent below 1/2 throttle but it really pulls at full throttle

What this leads me to think is that I might be near stoich above 3/4 throttle and running lean near idle and below 3/4 throttle.

So am I correct in my guess? Im new to carb tuning so im just looking for some things to try so that I can get some experience and hopefully get to run really nice and powerful

thanks

 

[rockcitycafe]

i'm not an expert on carbs, but it sounds like it is lean in the lower portion of the throttle travel, try playing with the idle mix screws, and perhaps the needle is a little too low

 

[Kuyarico]

Was your old air filter a pod type filter or more of a stock setup? You may need to rejet the carbs. The best way to know if you're running rich or lean is to look at the spark plugs. Ideally, they will have a burnt tan color. If you are running rich, it will have a dark carbon color. And if you're running lean it will look white-ish and burnt up. Not good. I'm suspecting that you are running lean due to the pods. Before you do anything, put some filter oil on the pods. I used K&N filter oil. But this alone may help you out.