13-05-15, 07:21 AM
The aftermarket exhaust shouldn't be a problem, my fazer ran OK on the Sandybikespares downpipes and exhaust.
It is possible to get yourself in a tangle when balancing carbs if you try to do them in the wrong order. Match them in pairs: 1&2 then 3&4, then balance the left pair to the right pair. It requires a bit of alteration to the idle screw, once they're matched the revs will usually be a bit high so tweak it down and then adjust the balance again.
Once you've done all that, the throttle position sensor will need a check.
The "balancer" hoses are for the heater system to prevent carb icing.