Deceleration popping

Acidreamer
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Acidreamer
Have an 09 kx 450 with full pc ti5 pipe. Run 110 oct cam2 gas in it. HC wiseco piston.

Having some popping issues on deceleration. Checked my valves as my initial thought was tight exhaust valves. All that is in check.

Only other thing i can think of is the bike is injecting too much gas and some of its getting into the pipe and causing the pop.

Not sure of anythIng else i could be overlooking. I dont hear this from other bikes at the track. Is this normal or due to a somewhat hopped up motor?

The pops arent loud gunshot like backfires. Just small pops.
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suzukirmz250 11/2/2017 3:09pm
11/2/2017 3:09pm
I had that probably turned out it was a little to rich but could be different for your case ,did you have it remapped
Acidreamer
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Acidreamer 11/2/2017 3:11pm
11/2/2017 3:11pm
No. I bought the bike used. As far as i know the pipe was done with no remap.
RCF
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RCF 11/2/2017 3:25pm
11/2/2017 3:25pm Edited Date/Time 11/2/2017 3:27pm
You shouldn't be running cam 2 in that bike ,it's design for old muscle cars it's really high in lead good for 2-stroke and old cars with steel heads and steel valves. all modern gas for four strokes are LEAD free for a reason. I didn't even think you can still buy cam 2

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BobPA
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BobPA 11/2/2017 3:34pm
11/2/2017 3:34pm
colintrax wrote:
Probably too lean
Yep, decel popping through the exhaust is most likely lean.

Leaded fuel is perfectly fine for modern four strokes, just not needed in your application.
Acidreamer
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Acidreamer 11/2/2017 5:56pm
11/2/2017 5:56pm
colintrax wrote:
Probably too lean
BobPA wrote:
Yep, decel popping through the exhaust is most likely lean.

Leaded fuel is perfectly fine for modern four strokes, just not needed in your application.
So with the pc pipe its running too much air. Makes sense. I buy the race gas because the bike wont start on 97.

Sounds like i need a remap or deal with it.
colintrax
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colintrax 11/2/2017 5:58pm
11/2/2017 5:58pm
colintrax wrote:
Probably too lean
BobPA wrote:
Yep, decel popping through the exhaust is most likely lean.

Leaded fuel is perfectly fine for modern four strokes, just not needed in your application.
Acidreamer wrote:
So with the pc pipe its running too much air. Makes sense. I buy the race gas because the bike wont start on 97. Sounds like...
So with the pc pipe its running too much air. Makes sense. I buy the race gas because the bike wont start on 97.

Sounds like i need a remap or deal with it.
I wouldn't just deal with it, get a remap. It'll reduce the popping, make the bike more quick, and might help you get more life outta topends.
imoto34
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imoto34 11/2/2017 8:59pm
11/2/2017 8:59pm
Did it randomly start popping? Seen many header leaks on those bikes. Since you already do top ends every 10 hours, a small investment for a tuner is well worth it.
Paw Paw
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Paw Paw 11/2/2017 9:56pm
11/2/2017 9:56pm
If the pipe was pulled or replaced and a new exhaust gasket was not installed it will cause a lean condition in the pipe and cause your issue. Try replacing that gasket and see if that cures the issue before doing anything else.

Paw Paw
Acidreamer
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Acidreamer 11/3/2017 6:04am
11/3/2017 6:04am
imoto34 wrote:
Did it randomly start popping? Seen many header leaks on those bikes. Since you already do top ends every 10 hours, a small investment for a...
Did it randomly start popping? Seen many header leaks on those bikes. Since you already do top ends every 10 hours, a small investment for a tuner is well worth it.
Its always popped but ive never thought anything of it since everything is in spec and tuned right mechanically.

Someone pointed it out to me and since then ive noticed not every bike does it.
Paw Paw
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Paw Paw 11/3/2017 11:20am
11/3/2017 11:20am
Again, I will bet that when the new pipe was installed the old exhaust gasket was reused and thus is leaking and causing a lean condition in the exhaust that is causing the popping. I see this a lot. Folks will spend hundreads of dollars on a new pipe and then scrip and reuse a $4 gasket.

Paw Paw
Giygas
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Giygas 11/3/2017 12:09pm
11/3/2017 12:09pm
Paw Paw wrote:
Again, I will bet that when the new pipe was installed the old exhaust gasket was reused and thus is leaking and causing a lean condition...
Again, I will bet that when the new pipe was installed the old exhaust gasket was reused and thus is leaking and causing a lean condition in the exhaust that is causing the popping. I see this a lot. Folks will spend hundreads of dollars on a new pipe and then scrip and reuse a $4 gasket.

Paw Paw
Paw Paw,
I noticed you're in Benton. Do you ride local tracks? I live in Shreveport.
Paw Paw
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Paw Paw 11/3/2017 12:30pm
11/3/2017 12:30pm Edited Date/Time 11/3/2017 12:34pm
Paw Paw wrote:
Again, I will bet that when the new pipe was installed the old exhaust gasket was reused and thus is leaking and causing a lean condition...
Again, I will bet that when the new pipe was installed the old exhaust gasket was reused and thus is leaking and causing a lean condition in the exhaust that is causing the popping. I see this a lot. Folks will spend hundreads of dollars on a new pipe and then scrip and reuse a $4 gasket.

Paw Paw
Giygas wrote:
Paw Paw,
I noticed you're in Benton. Do you ride local tracks? I live in Shreveport.
I have a membership at SWAN in Tyler and that is my main riding track. I have been going there for about 34 years now. I did ride regularly at Desoto in the past. I also ride at Red Bug on occasion. I have ridden at Dirt Slingers from time to time. My riding days are limited due to health issues. I normally ride with some riders of my own age group ( over 70) and we have just as much fun riding together as the kids do. I normally do the Diamond Don's even each year and the Desoto Vet race in October, but not this year. My riding buddies and I do make riding trips on weekdays to Rio Bravo and Three Palms from time to time. From time to time I go to South Louisiana and ride Hwy 70, Down South and Gravity Alley.

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Acidreamer
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Acidreamer 11/4/2017 6:26am
11/4/2017 6:26am
Paw Paw wrote:
Again, I will bet that when the new pipe was installed the old exhaust gasket was reused and thus is leaking and causing a lean condition...
Again, I will bet that when the new pipe was installed the old exhaust gasket was reused and thus is leaking and causing a lean condition in the exhaust that is causing the popping. I see this a lot. Folks will spend hundreads of dollars on a new pipe and then scrip and reuse a $4 gasket.

Paw Paw
Im waiting on that gasket this morning. Gotta love RM’s overnight shipping. Ill let you guys know what happens at the track today.
23champ
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23champ 11/4/2017 9:06am
11/4/2017 9:06am
You can also adjust throttle position sensor to get into the next fuel cell to richen it up a bit.

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Richard Tease II 11/6/2017 12:33am
11/6/2017 12:33am
Try this it worked for one of the factory teams i was at a test day with 2 months ago. The team couldn’t get the pop to go even with remapping so they used the washer and it stopped.
Put an washer under the spark plug to increase the distance from electrode to top of the piston.
It’s quick and cheap.
Acidreamer
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Acidreamer 11/6/2017 4:32am
11/6/2017 4:32am
I replaced that crush washer for the header. The old one was damn near melted away lol! Didnt fix the problem so ill try to remap.

If more people give credibility to moving the spark plug ill try it. Speaking of which i didnt try a new plug yet.
526
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526 11/6/2017 5:09am
11/6/2017 5:09am
Have you ever Repacked the Silencer?
Paw Paw
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Paw Paw 11/6/2017 5:49am
11/6/2017 5:49am
Acidreamer wrote:
I replaced that crush washer for the header. The old one was damn near melted away lol! Didnt fix the problem so ill try to remap...
I replaced that crush washer for the header. The old one was damn near melted away lol! Didnt fix the problem so ill try to remap.

If more people give credibility to moving the spark plug ill try it. Speaking of which i didnt try a new plug yet.
That sure indicates it was leaking. It also tells me you are running real lean when you chop the throttle. You may be able to correct that with a TPS reset. It may also have a partially clogged injector that needs to be cleaned.

Paw Paw
Acidreamer
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Acidreamer 11/6/2017 2:04pm
11/6/2017 2:04pm
Acidreamer wrote:
I replaced that crush washer for the header. The old one was damn near melted away lol! Didnt fix the problem so ill try to remap...
I replaced that crush washer for the header. The old one was damn near melted away lol! Didnt fix the problem so ill try to remap.

If more people give credibility to moving the spark plug ill try it. Speaking of which i didnt try a new plug yet.
Paw Paw wrote:
That sure indicates it was leaking. It also tells me you are running real lean when you chop the throttle. You may be able to correct...
That sure indicates it was leaking. It also tells me you are running real lean when you chop the throttle. You may be able to correct that with a TPS reset. It may also have a partially clogged injector that needs to be cleaned.

Paw Paw
Im going to give all of that a try. I noticed my high idle and normal idle isnt a whole lot different. I think i twisted the knob and messed it up. Might be a cause too.
dirtmike86
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dirtmike86 11/7/2017 11:44am
11/7/2017 11:44am
I had a 09 when they came out. Had a recall on the throttle body. They were cracking. Mine never did but i got it fixed anyways. My 13 kx450 popped i bought it used and the tps was slightly off.

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