how bad is it to run without the stock baffle in an 03 z400 exhaust
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04-12-2008 | 05:42 PM
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how bad is it to run without the stock baffle in an 03 z400 exhaust
I don't know. I know everybody says to up your jet size when you reduce backpressure, but that doesn't seem to work for me.
1) 2005 stock Honda 250EX. Take baffle out. Plug black as coal.
2) 1999 Kawi 220 bayou. Take baffle out. Plug black as coal.
3) 1986 230s. Exhaust gutted. Had to lean all the jets and move needle down.
4) 1984 Toyota Tercel. Everytime the muffler would rust out, the plugs got black. Replace muffler, it runs better and plugs stay cleaner.
The only thing I can think is that when you reduce backpressure, you actually INCREASE intake vacuum. What happens to your engine when you increase intake vacuum all depends on how your engine is set up. It will either satisfy that vacuum by letting more air in, or more gas... Which ever is easier to do. Vacuum will follow the path of least resistence just like electricty. It turns out in my cases, it caused the engine to suck in more gas rather than air and threw the mix off in the rich direction.
Here's what supertrapp has to say about it: (read at the end)
Q. Why do some aftermarket pipes backfire when you decelerate?
Backfire, or "lean misfire" on deceleration is primarily attributed to an improperly tuned engine. Under this circumstance, the low speed fuel circuit needs to be adjusted. On a street bike, the rule of thumb is to adjust the fuel mixture screw out in ½ turn increments to add fuel. If you reach 3.5 turns out and it still pops on decel then go up one size on the pilot jet and turn the fuel mixture screw back to one turn out from bottomed. Repeat this process until the misfire is eliminated. In some cases, this problem is an indication that the exhaust is too free flowing (i.e. Head pipes too large in diameter or muffler core is too large) for the motor configuration you have. As always, check your spark plugs to verify the tune is correct. The plugs should be a light tan in color if tuned properly. If the exhaust is too "free flowing" you will ultimately add too much fuel which will cause an excessively rich condition and foul the plugs.
http://www.supertrapp.com/resource/faqs.asp
1) 2005 stock Honda 250EX. Take baffle out. Plug black as coal.
2) 1999 Kawi 220 bayou. Take baffle out. Plug black as coal.
3) 1986 230s. Exhaust gutted. Had to lean all the jets and move needle down.
4) 1984 Toyota Tercel. Everytime the muffler would rust out, the plugs got black. Replace muffler, it runs better and plugs stay cleaner.
The only thing I can think is that when you reduce backpressure, you actually INCREASE intake vacuum. What happens to your engine when you increase intake vacuum all depends on how your engine is set up. It will either satisfy that vacuum by letting more air in, or more gas... Which ever is easier to do. Vacuum will follow the path of least resistence just like electricty. It turns out in my cases, it caused the engine to suck in more gas rather than air and threw the mix off in the rich direction.
Here's what supertrapp has to say about it: (read at the end)
Q. Why do some aftermarket pipes backfire when you decelerate?
Backfire, or "lean misfire" on deceleration is primarily attributed to an improperly tuned engine. Under this circumstance, the low speed fuel circuit needs to be adjusted. On a street bike, the rule of thumb is to adjust the fuel mixture screw out in ½ turn increments to add fuel. If you reach 3.5 turns out and it still pops on decel then go up one size on the pilot jet and turn the fuel mixture screw back to one turn out from bottomed. Repeat this process until the misfire is eliminated. In some cases, this problem is an indication that the exhaust is too free flowing (i.e. Head pipes too large in diameter or muffler core is too large) for the motor configuration you have. As always, check your spark plugs to verify the tune is correct. The plugs should be a light tan in color if tuned properly. If the exhaust is too "free flowing" you will ultimately add too much fuel which will cause an excessively rich condition and foul the plugs.
http://www.supertrapp.com/resource/faqs.asp
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