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Discussion Starter #1
This is a new to me Honda Shadow Aero. It has 37k miles. Bike is in pretty good shape with just a couple issues. Previous owner said it sat for two months then it started to pop out of exhaust on deceleration.

Carb mix screws are at 2.5 turns out. Battery was at 12.06v as I just tested it. At idle bike charges at 13.8v. When I increase rpms at idle charge drops to 13.14v. Is this normal? I'm charging the battery right now but I'm sure it'll need a new one. Anything else I should look for on this bike?
 

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You want to check the 3 yellow wires that come from the stator, the plug in connector is not the best and has caused a lot of problems, it gets corroded and gets hot enough to burn things up, just about everybody solders them to elimate that problem. Your OK in the chargeing dept, the output is rated at 3000 RPM and a slight drop is OK.

If you speed up the idle a bit the popping should stop or at least get better.
 

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Discussion Starter #3
Thanks I appreciate it. I haven't had a honda bike in a while. Last one I had was a cb750 and I had to change rotor on that one...
 

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Discussion Starter #4 (Edited)
Got myself a portable tach...set idle to around 1000 when warmed up. Changed two of the spark plugs. Still get the pop/backfire on decel, ****. Any other ideas?

Exhaust manifold seems to be tight, air filter is clean, emptied the overflow drain on bottom of bike. Only thing I've noticed that was odd - when I changed the two plugs (didn't realize till later there were four plugs) - electrode tip of plugs were wet with gas. And this was when bike was cold and hadn't been run for a day.
 

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You have a lean condition in the idle circuit - run some seafoam or berryman fuel cleaner through a couple tanks of gas to see if you can open up the idle jets a bit - they may have gotten munged up from sitting and it will probably be ok.

The other option(if you can't wait for the cleaner to work) is to turn out carb mix screws until the popping stops start with 1/2 a turn more and continue until the popping subsides - if you get near 4 turns you shoud dab some silicone rubber in the hole so a needle doesn't fall out.

The good news - al little popping on decel is quite normal and doesn't hurt anything. From the factory they often pop on decel so they can meet EPA requirements.
 

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Discussion Starter #6
Popping is putting it mildly :) I also put the other two new plugs in today. No difference. Held one of those long handled grill lighters up where pipes meet the jugs to see if there was an exhaust leak....flame didn't blow out....so i'm assuming there is no leak.
 

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Discussion Starter #7 (Edited)
I just realized I didn't rev the bike with the flame near the flange so that MAY be worthless.

I did spend some time playing with the screw position and driving it up and down the street. I went anywhere from 2 - 3.5 turns out a 1/2 turn at a time then test driving it. 2.5 turns seems to have the least in the way of popping. I guess I'll start looking for exhaust gaskets. I have searched all over the internet and in my Clymer's manual and still can't find whether or not my bike has a PAIR valve.....

I've had the bike for two weeks now maybe. Only driven it about 60ish miles due to work and other projects. I'm keeping seafoam in the tank so hopefully the "mechanic in a can" can thin out any junk in the carbs. I've also read that Yamaha's carb cleaner is very good for removing gunk....anyone have any experience there?
 

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Discussion Starter #8
I put the bike in the garage got it warmed up and held the grill lighter around the exhaust manifold and revved it. Flame flickered and went out around front gasket area - so as soon as my new gaskets come in hopefully the backfire will be gone!
 

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Discussion Starter #10 (Edited)
Just got back from bike week. Bike runs so rich you can smell it. Averaged 23 mpg. Lots of backfiring on decel and now even just sitting at a red light. I'm gonna take it tomorrow and get carbs cleaned out/balanced/sync'd. I've turned the screws out, put Seafoam in gas tank. I don't get it. It will even backfire some if i pull in the clutch.

This is not "popping" just to clarify. This is a "bam" out of the exhaust pipe. And its never just one. Only other thing i've noticed is if you let off the throttle a little it will surge a little. And I also noticed when you first get going it wants to hesitate once or twice - which also makes me think its running rich. And it takes 5-6 pushes of the button and various positions of the choke to get the bike to start.

Bike runs great when its warm. Sounds great and cruises down the road really nicely.
 
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