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Excessive Popping on Decel

301 Views 9 Replies 9 Participants Last post by  "Captain D", 
Slowpoke1675
I have an 03 ACE that I just recently replaced the seals in the carburetor, I had some issues before with major popping on deceleration while I fixed it for a few, they have recently returned. Yet when I'm riding and kill the engine, popping stops entirely.
My current air fuel screws are seated at 3 1/4 turns, it was working well before, I've tried the stock 2 1/2 and the popping remains, cant tell if its less or more then what I have it set to. Contemplating going lower but I don't want to completely choke the motor of fuel.
I have a stock air filter, thinking of going to K&N, tomorrow I'm going to check if the air filter boots are properly seated on the carb. Also there's a small leak coming from the petcock, near the base.
I have Vance and Hines straight pipes, previous owner put them on, someone told me I should have my carburetor re-jetted when getting new pipes as adding them makes it very lean, I'm not sure if the previous owner did and I couldn't quite tell when I took the carburetor apart the last time. He also mentioned I should get my carb synced, which I didnt know could be unsynced after riding for some time, I have no knowledge on how to even approach that situation.

TLDR; Popping on decel, very annoying, changing air fuel mixture seems ineffective, what are my next steps? Take it to a shop? New Jets?
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D's Spirit
From your description it sounds like re-jetting the carbs would be in order. You can contact Vance & Hines on their support page and I would think they would have a recommendation on what jet kit to use. Probably a good time to give the carbs a good cleaning while they're off as well.

Synchronizing your carbs is fairly simple. The Honda shop manual will give you detailed instructions. (You can also do a bench sync while the carbs are off which will get them working really close.)
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swifty2014
Some models have an air cut valve on the carb that is supposed to control decel pop.
But with aftermarket pipes with no crossover tube, it makes the popping worse.
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G
Decel popping is a normal condition of a well tuned engine. Most vehicles hide this with extensive exhaust systems. Straight pipes make the sound more prevalent. The condition is caused by backing off the throttle and the pilot jet and pilot screw (A/F) are not providing enough fuel. Killing the engine means no ignition so no popping. There are a few things to try:
1. Reset the pilot screw more rich. Seems like you have done this at 3.25 turns out and near the max but you can go to 4 turns out and then cover the screw so it doesnt fall out due to reduced spring tension.
2. Reduce air flow (and noise) by installing baffles in the straight pipes. (PS I am a fan of stock air cleaner).
3. Rejet the pilot jet. Go up one size.
4. I recently solved this by merely turning up the idle using the throttle stop screw. Wow that was simple. The person had the idle way to slow so every time they backed off throttle, they were starving the engine. Turned the screw about 1/2 turn and popping almost gone.
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oldguy
+1 on adding baffles (some inexpensive "can opener" baffles in the correct diameter for your pipes.) and leaving the stock air cleaner in place. maybe go one size up on the pilot jets or try increasing the idle speed a bit as mentioned above.

I drill holes in the caps for my small screwdriver, then re-install the caps so the pilot screws don't fall out.
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"Captain D"
Common for these to pop a little, Welcome Slowpoke1675
Which ACE? 750? 1100?
You might try Closing the throttle to Full Stop when slowing too...
I`ve found this does wonders,
Dennis
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punxsybob
"Captain D" said:
ou might try Closing the throttle to Full Stop when slowing too...
Click to expand...
I leave my throttle cracked open just a bit when slowing down.....I love a good decel pop! :p
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Peppysfireball
I just had new pipes and rejetting done. The mechanic told me it's very difficult to get rid of the popping due to California emissions regulations. I like when mine does it actually.
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CSRoad
I'll go along with @oldguy's advice on this #42 pilots would reduce popping, you'd still have to play with the mixture screws, I'd start at 1 1/2 turns out from gently seated with the new pilots and see how it does. The more you turn the screw out the richer both the idle and pilot circuit gets.
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"Captain D"
Yes, I agree >
I like when mine does it actually.
&
I leave my throttle cracked open just a bit when slowing down.....I love a good decel pop! :p...

I think it`s part of the enjoyment of Riding,
Dennis
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