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Discussion Starter #1
While I really don't know how to read spark plugs, I believe that these indicate that my bike is running lean?



And..



This is a 2009 V Star 650 with a little over 5k miles on it. I bought the bike used last fall when it had just over 4k miles. Since I have owned it, the exhaust tends to pop on deceleration, it is a little difficult to start with full choke on (I just have to hold the starter for a few seconds before it finally turns over, but runs well after that) and has had some bluing on the front pipe...



I do believe the bluing has gotten worse since I've been riding it. It starts out as a very dark blue and turns to a gold color. Sort of.

The pipes are stock. The air filter was pretty dirty when I got around to inspecting it, so I replaced it with a K&N filter. The popping and bluing existed before replacing the air filter.

Per the suggestions on the questions I asked here:

http://www.starbikeforums.com/forums/showthread.php?t=64769

I took the tank off and snugged up all of the air intake bits around the carburetor and also ran a can of SeaFoam through the gas tank (not the entire can at once). I did not replace the fuel filter, as I didn't think it would be necessary at only 5k miles.

The previous owner didn't treat his fuel for ethanol and I suspect left it stored much of the winters he had it (from 2009 to 2014). He did tell me that the bluing on the pipes only started the last year or two he had it.

Could it be the fuel filter?

Does the PMS screw need adjusting? I do tend to drive like an old man (I'm not an old man tho) and cruise a lot in a high gear with the throttle not open that much.

Could the jets be partially clogged considering it was stored without fuel treatment often?

Could it be something else?

How do you suggest I approach this and in what order?

Thanks!
 

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I don't see any cause for concern just by looking at those plugs. A little ash on the plugs is normal.

Take a look at this page:

http://ngksparkplugs.com/tech_support/spark_plugs/faqs/faqread.asp

Your pictures are nearly a perfect match to the first picture...the normal one. The list isn't all inclusive, but still sufficient.
 

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K&N air filter will make it leaner than stock. AIS system causes this popping on decelleration. 2nd running the carb cleaner through it.
 

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Discussion Starter #5
I thought the AIS only caused popping if something wasn't tuned properly?

Does that K&N air filter cause enough of a lean condition where rejetting is necessary? Altho, if the plugs look good, I don't see why I would need to?

And....I'm still a little confused about what exactly is causing the bluing pipes. I presume that's not normal?

Thanks for the help!
 

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I thought the AIS only caused popping if something wasn't tuned properly?

Does that K&N air filter cause enough of a lean condition where rejetting is necessary? Altho, if the plugs look good, I don't see why I would need to?

And....I'm still a little confused about what exactly is causing the bluing pipes. I presume that's not normal?

Thanks for the help!
I've never seen a set of chrome pipes that didn't go blue near the heads.. That's why a lot of the bikes you see have heat shields covering the pipes near the heads that are chromed so you don't see the blue..
 

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I thought the AIS only caused popping if something wasn't tuned properly?

Does that K&N air filter cause enough of a lean condition where rejetting is necessary? Altho, if the plugs look good, I don't see why I would need to?

And....I'm still a little confused about what exactly is causing the bluing pipes. I presume that's not normal?

Thanks for the help!
the ais injects fresh air into the exhaust,the popping is caused by a lean condition,in a lean condition unburned fuel collects in the exhaust and gets ignited thru an open valve, i can't think what i read about it something like that.lol.
anyways you don't need to rejet just turn the pms screws out till the popping stops,quarter turn or so.
 

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Whats not being conveyed here is on the carb version 650 the PMS screws are capped from the factory. ( no tamper seal)

These caps Must be drilled out the gain access to the adjustments.
Not so easy to do unless you are very versed in how to do this.
I know from experience on my bike the adjustment can go way wrong
and end up making a carb useless. I had to buy a complete pair when changing my PMS settings due to one of the PMS screws being stripped
during the adjustment process. Very easy to strip out.

This epic fail cost me over $300.

These tamper seals are put in at the factory and mine just happened to be sealed so well the the threads on the PMS adjuster for the rear carb had residual resin or epoxy that dripped down inside and froze the screw in place. You could try to turn in but would not budge.
I stripped it out trying to change the setting.

I purchased a used pair of carbs and sold the old ones for parts.
Ever since everything has been fine.
 

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Discussion Starter #10
First of all, thanks guys for all of your responses!

Drilling the PMS plug doesn't sound like a lot of fun. If my bike isn't running lean, going from the condition of the plugs, would I even want to adjust the PMS?

Also, I understand that disabling the AIS isn't really an option with stock pipes, no? I'm almost getting the idea that I should just ignore the popping and bluing and keep riding it?

For what it's worth, turning up the idle does help quite a bit with the popping.
 

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Also, I understand that disabling the AIS isn't really an option with stock pipes, no? I'm almost getting the idea that I should just ignore the popping and bluing and keep riding it?
I have stock pipes and air filter and had popping on decel.. It is the AIS creating the popping as it injects fresh air in the exhaust to ensure all fuel is burned.

I disabled my AIS and no more popping on decel... http://www.650ccnd.com/ais.htm

Mine is a 2009 650 classic with 6000 miles.
 

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Discussion Starter #12
I thought the disconnecting the AIS could lead to the catalytic converter in the stock exhaust going bad? I understand disconnecting the AIS is almost a must for after market exhaust though.
 

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The extra fuel going into the cats will carbon up the material over time because the air isn't present to keep the cats hot enough to burn it properly. It does however take a while to do it as long as the carbs aren't too rich.
 

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2009 should have catylitic converters so disabling the ais is not recommended.keep using carb cleaned berrymans is less costly and it may clean the carbs,the passages could be restricted with varnish giving the lean pop.i don't think it's recommended to overuse though,you might want to check the idle with a tach for reference purposes.ha.the ais injects fresh air into the exhaust to burn unburned fuel before it gets to the cats,the cats can overheat and risk a fire.
 

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Common thought is that these bikes idle like a harley. No.
Idle speed that is border line stalling is way too low.
Sounds great. But not good. These motors need a warmed up idle speed right around 1050 to 1150 rpm.

With no tach this is hard to figure out. Single wire tachs can be purchased on the cheap from Ebay. Battery powered one wire attaches to the spark plug lead. Can be mounted where you can view
the readings. Also they can be purchased with an hour meter function and tach. when off it reads hours and when ignition is on displays the engine RPM. I've had mine for several months and works very well.
No issues.

Popping from the exhaust on decel is very common in multiple configurations until the AIS has been disabled. There are some cheap and easy disable methods that require no removal only rendering it inoperable. This will work on the stock bike/
 

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Since many folks change out their exhaust, the world is full of stock pipes laying around that can be bought fairly cheap. Find a set of pre 06 stock mufflers (w/o the cats) then you can eliminate your AIS and your problems are done. That is, of course, if you want to retain your stock pipes.
Just a suggestion
 

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Discussion Starter #17
All great suggestions. I just wanted to thank everyone again for all of the help and pointing me in the right direction. I have been enduring the popping for the time being, as I haven't had time to come back around to the issue. The popping doesn't bother me that much, as long as my engine is healthy, but I will consider some of the recommended steps to resolve it soon. Thanks again!
 

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http://www.mikuni.com/tg_backfires_in_exhaust.html here is a good explanation how a lean condition causes popping and can be controlled thru the idle circuit and adjusting the pms screw,it also says a supply of fresh air can increase popping like a exhaust leak or maybe an ais system.
One of my vacuum caps popped off the other day, causing instant lean, and the popping was nuts - sounded like a firing range every time I let off the throttle. Too lean will definitely cause popping.
 

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The popping doesn't bother me that much, as long as my engine is healthy
I enjoy a little popping. Reminds me I'm on a carbureted engine. I was told many year ago that if you're on a carb, you can adjust it to work today but tomorrow if the temp, humidity, and altitude changes, it will pop. This is not a back-fire. I was told it's a after-burn. Back-fires go back thru the carb and after-burn is excess fuel burning in the exhaust.
 

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I enjoy a little popping. Reminds me I'm on a carbureted engine. I was told many year ago that if you're on a carb, you can adjust it to work today but tomorrow if the temp, humidity, and altitude changes, it will pop. This is not a back-fire. I was told it's a after-burn. Back-fires go back thru the carb and after-burn is excess fuel burning in the exhaust.
I'm with you that a little popping is actually kinda cool. What I had was rat-a-tat-tat nonstop. Way past cool and well into the WTF zone.
 
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