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So...the ultimate question is if the poping actually harms the bike?
The only harm that can be done is additional heat in the exhaust track that can cause fatique wear on your pipe and exhaust can.....but this is unlikely.
 

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Discussion Starter · #24 ·
So, I read in here that someone said with the lean mixture that it can cause your engine to run hotter than it should? What temp are you guys running at? This is a 07 gsxr 6, usually cruising the freeway its at 180f, when im going through town and stuck at lights and such it's anywhere from 200-220f (fans kick on at 220).

I'm going to search around on how to remove this damn valve...
 

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So, I read in here that someone said with the lean mixture that it can cause your engine to run hotter than it should? What temp are you guys running at? This is a 07 gsxr 6, usually cruising the freeway its at 180f, when im going through town and stuck at lights and such it's anywhere from 200-220f (fans kick on at 220).

I'm going to search around on how to remove this damn valve...
Not necessarily hotter as in increased coolant temperatures - yeah you might see a few degrees maybe but the exhaust gas and cylinder head temperatures are highest at near the stoichiometrically correct AF ratio. This in itself won't hurt your engine.

Cruising around town or riding on the highway with a lean mixture will not hurt your bike either. In fact it will be better for it. Where it's an issue is at full or nearly full throttle, when your engine is producing near its maximum amount of power - this is where where detonation and/or valve burning can occur if you are too close to the ideal AF ratio.

The temperatures you're running are perfectly normal and well within the limits of the engine.
 

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Actually, it is going to tear up your engine at high rpms or heavy loads, like acceleration. Detonation is more likely to take place when your piston is moving at higher speeds. I would rather have less power and my bike be safe than make max power and ruin burning a valve or knocking a hole in a piston.
 

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Discussion Starter · #27 ·
Actually, it is going to tear up your engine at high rpms or heavy loads, like acceleration. Detonation is more likely to take place when your piston is moving at higher speeds. I would rather have less power and my bike be safe than make max power and ruin burning a valve or knocking a hole in a piston.
So to fix the REAL problem of it being too lean I would need to pub on a Power Commander and have them run the dyno?
 

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alright i'm about a month late... but i changed my exhaust and it popped but i didnt change the header gaskets...so i bot new ones of those and put em in...and now the popping is gone... but i guess you said its a slip on so nevermind what i just said...i'm drunk.
 

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When I use the term "lean", I mean leaner than the stoichometrically correct mixture. Remember that the A/F map isn't constant over the entire power band. You are correct in that these engines have to run rich at high power and throttle settings, but they can run perfectly well at the stoichometrically correct A/F ratio or leaner at cruise power settings.

Most newer car engines are actually run lean of the stoichiometrically correct mixture all the way through their power band. They are able to do this through 02 sensor feedback loops (there is an excess of air in this condition), low compression ratios, relatively low power outputs, and knock sensors to retard timing. Note that some new bike engines also use 02 feedback loops to run in a lean condition, although a high performance bike engine will still run rich at high power or throttle.

As a side note, aircraft engines have many of the same problems that high performance bike engines have with respect to detonation, and high cylinder head and valve temperatures. At high power settings, they can either be run very rich, or lean. Running them rich causes fuel to cool the cylinders and valves and control detonation, and running lean causes excess air to do the same thing. This is actually the preferable way to operate these engines, as they last longer, have less fouling and carbon buildup, and are more efficient. Of course, they run at the same speed for hours on end so it's possible to practically control the mixture to keep the engine in a safe operating regime.

There are basically two ways you can regulate mixture control for engines that run lean. One is using oxygen sensors, like most modern cars, and the other is by exhaust gas temperature, which is used in piston aircraft. If you were to measure the temperature of the exhaust, you would find that as you lean the mixture from a rich condition, the temperature of the exhaust increases. It peaks out at some point near the stoichiometrically correct mixture, and starts to decrease as you further lean. Roughly 50 degrees rich of the peak EGT is the "best power" mixture for most engines, and the highest valve and cylinder head temperatures occur at about 25 degrees rich of the peak EGT. So actually, some of the most destructive conditions for an engine are still on the rich side. Typically, once you're past 50 degrees lean of peak EGT, you're out of the region where detonation and valve burning is an issue.
I joined the forum purely to say ‘like’ regards your post…brilliant 👍🏼
 

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I joined the forum purely to say ‘like’ regards your post…brilliant 👍🏼
The links are cool, but his explanation of perfect stoichiometric mixture, exhaust gas temperature peak, and best power mixtures leave very much to be desired.
 
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