Backfire on deceleration and off idle stumble

[Biebs]

1992 Nighthawk 750 just install the Delkvic 4 into 1 megaphone exhaust. Bike has noticeable midrange power gains. I now have a off idle stumble and backfire on deceleration. Guessing it is running lean off the idle air mixture screws. At hot idle runs about 1500 rpm - need to adjust down to 1000 rpm. Before new exhaust install idle was 1000 rpm I will adjust it down.

Question is are the idle mixture screws accessible on the 1992 bikes?? Or are they capped from the factory.

Anyone with experience on the 1992 ( 1991-?? Models). Let me know. Other quick fixes??

TIA

 

[Biebs]

Adjusted idle back to 1000 rpm. Much better running off the idle circuit.
Found idle mixture screws on the bottom of carbs not capped - will adjust out 1/4 to 1/2 turn and test.