Coughing and shutting off

I have an '02 deuce with stage one air cleaner and vance and hines big shots with the baffles cut in half. My prob is the carb. When i bought the bike it had drag pipes on it and the air cleaner. After i put the big shots on i really noticed it coughing thru the carb frequently but only when i downshift and blip the throttle. pulled the bowl off and it had a 195 main jet in it and a # 45 slow jet in it. i swapped the main to a 185 and still have the same prob. removed the carb from the bike, tore it apart, cleaned it and picked up a gasket kit. which jet kit should i get and is the 45 slow jet too big? read a ton of articles and im confused on which way to go. thanks for any help

I'd start out with a 48 slow and put back in the 195. Turn the mixture screw in to lightly seated and then back out 2 1/2 turns. Cutting the baffles in half really cuts down on back preasure so you're almost running drag pipes. Also check for any air leakes in the exhaust as that will cause popping.

why are the baffles cut in half, that is probably part of your problem. V&H are loud enough with the complete baffle in.
try the 46 and see if that helps. check for air leaks even at the exhaust fittings

IT NEEDS BACK PRESSURE ! A Harley Engine needs BACK PRESSURE WITH THE EXCEPTION OF THE OLD FLATHEADS!
Put longer baffels or a nice muffler on those pipes there giving me a Headache

And I would check the manifold and carb for leaks 1st Before you do anything else...You cant get a carb tuned in with air leaks!

ok thanks for the insght. i will try the 48 slow jet as well as the 195 main and see where that puts me. will keep posted as what i make out

my other question is the big city thunder baffles. my dad has them in his '01 superglide with the v&h big radius with no problems. it has the dynojet thunderslide kit in it also. i understand how backpressure works but am confused becuz of the design of the bct baffle. should i install those baffles then try and jet the carb? again thanks for everyone who comments. i learn from everyone. Harleys forever

use the baffels V & H makes there made for there pipes and will most likley get you the best performance

Don't know where the popular misconception that a H-D (or any) engine "needs" backpressure came from as it's been around forever, but it's not true. The tuning problem with H-D engines is twofold - the "odd-fire" nature of the design (firing order = 315º - 405º in terms of flywheel rotation) & "reversion" - the pressure waves that go back up the pipes & are even more important than those going down. Unrestricted, the "reversion" waves really screw tuning up & baffles are designed to break them up & minimize the effect. Also, numerous stock exhaust systems have a crossover pipe to equalize the "reversion effect" & the crossover actually does work.

A key factor, more so with Big Twins than Sportsters, is cam timing "overlap" - the period when the intake & exhaust valve are both partially open - intake is opening before the exhaust has closed all the way. During overlap, reversion coming up the pipe can go in the exhaust port, thru the cylinder, out the intake port, into the intake manifold & since we're dealing with an odd-fire engine, those waves hit the manifold @ irregular intervals. What you often see with straight drag pipes is one cyl. running rich & the other running lean. But it's NOT due to lack of backpressure, it's due to the fact that there's nothing to break those reversion waves up & reduce their influence.