Popping when decelerating
Cruiser
Joined: Mar 2008
Posts: 197
Likes: 1
From: Grey Duck
A couple of things for you to look at, whenever an after market exhaust is put on or for that matter when ever the head pipe is loosened replace the exhaust gasket that goes between the head pipe and exhaust port. Do yourself a favor, their cheap. The same if you have "slip on" mufflers if loosened or removed replace the crossover gaskets. MoCo recommends the muffler clamps be replaced apparently they are only good once (I have never replaced mine =) but I can see little signs of leakage, not much though). Next check for intake leaks.The easiest way is to run the bike until it's warm, spray carb cleaner all around the rubber intake manifold. If it doesn't kill or make it idle high, you should be good. Intake or exhaust leaks will make your bike seem like it's running lean, in a way it is, your getting more air then gas. Once you made sure you have no leaks go for a ride. If you still have popping pull the choke (enrichener) about half way out. If the popping goes away you now know for sure you are still to lean. Now don't go thinking riding with the choke half way out is the solution, adjusting the carb really is easy. If you don't know for sure you may have to remove the carb. Check the bottom of the carb to see if the air /fuel mixture screw has been "revealed" (they come sealed from the factory, you know E.P.A. regs.) it should be with the mods that are already done to it. If its not don,t worry it's easy.If it is, back screw out to 3 1/2 turns (no more you don't want it falling out, bad bad bad) take it for a test ride. If that doesn't fix it then you need to go to the next larger size pilot (slow) jet. Stock is 42 I run a 45. These steps should solve 90% of stage 1 carb issues.
Tourer
Joined: Mar 2007
Posts: 368
Likes: 2
From: Salina, KS
Also the Vance & Hines, without baffles were on too. I have leaned out (screwed mixture screw in a quarter turn) and seems to have made a diffrence. Screw is now 1 7/8 of a turn out. Its not a drastic terrible thing, but I just want my Harley to run 100% you understand. On a limited budget."
Do your plugs look rich or lean?
Check out the Big City Thunder site for some Thunder Monster baffles. They will restore the power curve, and also probably reduce the popping you are hearing. Probably improve the sound, also. The site also has a nice explanation of how the exhaust system works.
Last edited by rfranz1952; Oct 25, 2008 at 09:44 AM. Reason: clarity and completeness
Cruiser
Joined: Mar 2008
Posts: 197
Likes: 1
From: Grey Duck
No baffles? (I have to read these threads better) He's right back pressure is your friend unless you are just going to drag race the thing low rpms aren't a factor but upgraded valves and pistons will be your future. However I still think you're too lean. Check your plugs, try the choke trick . Your valves will be much happier if you run some baffles or at least some torque cones. I think your V&H's will still sound nice but more importantly they will work like they're designed to. Good Luck
Road Master
Joined: Nov 2007
Posts: 1,223
Likes: 3
From: Peoria, AZ
Too lean. Richer makes it go away. I disagree with drags and having to live with popping. I have 1 3/4" drags on my Sporty and have dynoed to pleasing muffled decel "pop" sound at 13.5 AFR with #48 and 175 main. Any bigger diameter of drags I will agree is better for WOT application vice cruising.
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carb, cv, decelerating, deceleration, decellerating, exhaust, harley, harlydavdison, hines, jet, nivram39aolcom, popping, pops, radius, sizes, vance
