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Discussion Starter #1
Greetings.

I have a a 2007 VN900C with about 21.5k miles. It has Cobra speedster longs as only mod. When cruising or slowing down, the engine misfire's. However, when I speed up, it sounds fine. Both plugs and air filter were replaced last month. Old plugs were normal brown color. Bike never feels like it's losing power. Any ideas?
 

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Discussion Starter #5
It has decel pop. But it sounds like it cuts out while cruising at partial throttle. It is more apparent at highway speeds. Doesn't seem to effect overall performance.
 

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Discussion Starter #7
Part throttle cruise...what indications are you having that the engine is missing?
The sound of the motor. Other than that, I get no hesitation, no surging. Just sounds like the motor has a misfire while on partial throttle for cruise. I've had it well over 100 MPH before and it handled it like a champ. So, I don't know if what I am hearing is an actual mis-fire, or just normal noise due to aftermarket pipes. Considering the pipes are black inside, I image the bike is running a bit too lean.
 

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Greetings.

I have a a 2007 VN900C with about 21.5k miles. It has Cobra speedster longs as only mod. When cruising or slowing down, the engine misfire's. However, when I speed up, it sounds fine. Both plugs and air filter were replaced last month. Old plugs were normal brown color. Bike never feels like it's losing power. Any ideas?
You might try plugging the fresh air going to the PAIR system, also called "marbling" on this board. Do a search of this board and then temporarily plug the system to see if there's any change. It's all free.
 

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First thing I'd check is your battery connections to make sure they're tight. Small things like that can wreak havoc on a fuel injected bike.
 

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Discussion Starter #13
Well, that wasn't it. I found a how-to video using a yellow wire nut to shove into the hose. I still get the occasional loud pop and the engine stumbles / cuts out while cruising. Whatever it is, it's not interfering with the performance any.

If this bike was running rich, how could that happen if it comes from factory lean? There is no PC installed currently.
 

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1. How long have you owned?
2. Has it always done it or did it just start one day?
3. How long has it been doing it?
4. How does it start hot/cold?
5. How does it idle hot/cold?
6. Any other driveability issues, no matter how unrelated?
 

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Discussion Starter #16 (Edited)
1. How long have you owned?
2. Has it always done it or did it just start one day?
3. How long has it been doing it?
4. How does it start hot/cold?
5. How does it idle hot/cold?
6. Any other driveability issues, no matter how unrelated?
7. As an add, have the valves been checked?
1. Since December 2012
2. Seems to have been there since I bought it
3. Since I bought the bike
4. Starts right up hot or cold
5. Idles fine. Doesn't exhibit any symptoms @ idle.
6. None
7. Not since I have owned it. This is new to me since my last bike was a VN750 w/ self-adjusting valves.

Only other sounds coming from bike are the fuel pump and the idle circuit after warm-up.

EDIT, I just checked the battery and charging. Seems good. Battery @ +/-13V @ low idle and jump to 14.5+ when given some throttle. The battery is a sealed; so, I am think it is an AGM variant.
 

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Discussion Starter #18
I'll have a whole week for that middle of may. I just rode to work and the exhaust doesn't sound as bubbly as before I blocked the pair system. Still there somewhat, though.
 

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Discussion Starter #19
Well, after driving the bike since blocking the PAIR valve, the erratic engine sound seems to have disappeared. My last bike was a VN750 w/ Cobra exhaust and it had nasty decal pop, but didn't have the same sound during cruise as my 900 did.

Anyhoot, all is good now. Thanks for the help!
 
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