OZ ATV :: The Australian ATV Forum

[m0byd]

I replaced the stock pipe on my 300cc bike with a less restricted pipe. Its definately quicker with the new pipe on but it seems to be misfiing a bit when im giving it a bit of throttle. Its hard to tell if its running hotter because its been bloody hot here anyway.

I need someone to explain what putting the pipe on has done and whether it would be making the bike run lean or rich. Is there a way to tell? If i need to rejet the carby, do I need to get jets specific to my carbie or are they pretty similar? Would i get away with chaning the fuel mix with the fuel / air screws?

Any advice is really appreciated

[Noy Q75]

if you have just put a bigger pipe on you bike it will make a change to the way the bike runs . if its louder and quicker thats because you have increased the amount of air flow coming out of the bike there for yes it will make your bike run leaner . now you have changed the pipe you should change the air cleaner to a high flow then have the jetting done to suit the set up..but as for the missfireing under load i dont think your pipe has anything to do with that ? that mite be your coil or plug ??
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[ReD HeaderZ]

Open up the airbox for sure.....
K&N filter to get more air into the carb will get a better response again from the bike, you may need to rejet the carbie's, it depends where exactly in the rev range as to what part of the jetting needs changing...

[4stroker]

what sort of bike is it?

if the misfiring has only started since the installation of the new pipe, then it will be the jetting that is affecting it. too lean or too rich will cause the bike to stumble, obviously from not enough fuel or too much fuel...

it might sound weird but a really good pipe can cause a stock engine to run rich, because it will pull a really good signal through the carb and suck harder on the main jet...

jets are carb specific (eg keihin jets and needles are diff to mikuni jets and needles)

you can find the "jetting how tos" in the sticky post at the top of this setion of the forum, its all in there mate.
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