Help!!

I recently purchased a '98 Road King, 80in evo, cv carb and slip ons.

Bike ran ok but sat alot, had a hard time starting. I rebuilt the carb that supposedly had a stage one in it, I pulled the plug and set mixture at 2.5 turns out, I don't remember jet sizes.

After rebuilding (and before rebuilding), bike is hard to start, if I twist throttle one time then crank it backfires through carburetor, if I don't it backfires through exhaust. After couple tries it cranks and runs great but it'll scare the devil out of everyone in the parking lot when I first fire it up.
I took it to a local bike shop, they said it runs good. I know it runs good, I want it to be easier to start.
Any ideas?!?!

Would those things affect the bike just on startup? Bike runs like a top once it's fired up.

I did check for manifold leaks using the wd40 and starter fluid method, no changes in idle.

I have not checked the plug gap and I'll pull it back down to check the jets.

Welcome rooster521....jet sizes could help...Does it have a vacuum operated petcock?? and do you shut off the fuel when you park the bike??
How does scare people?? A loud bang,like a gun going off??

I'm thinking it could be fuel leaking past the inlet valve or too rich jetting,leaving unburnt fuel in the exhaust when you shut it down and when the bike fires up it ignites the fuel in the exhaust and then Boom...scares the hell outta anyone standing close by:roflmao:

This hear RK is the bes looken ride on hear next to JoshBobs shovel. I have a buddie that has a RK. Nice Ride!

my bagger did that when i first got it as well . i redid my cv 40 . and set it up as follows . 46 slow jet 195. main cv needle . i back the idle all the way down till it dd not touch the idle cam then ran it in till it just moved the cam and then one full turn . then did the same with the af screw all the way in then one full turn out . start the bike get it fully warmed up rocker box hot to the touch adjust your idle to 900 rpm now listen to the exhaust pay close attention the change is not huge in the drop. back the screw slow out and listen for the rpm to drop when it does its to rich run it in a quarter turn your carb is set . chances are the idle is set to low and your not getting air in the carb at start up once it fires up the engine vacum will move the butterfly in the carb just enough to keep it running at low rpm . hard starting and cough and pops out the exhaust . is a rich condition in the start sequence . also double check your intial timing as well but try the carb first you will be surprised how much better they start when the are set up correctlly.