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Tips to quieten down exhaust


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I have a 2010 250f and I'm doing a racing next week where it needs to be below 94 db. I have seen a test result where the stock ehaust was less than this. I have ordered an new exhaust but it might not get here in time for the race. what can i do to make it quieter if it doesnt pass that noise test?

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A lean jetted engine is louder and crisper.

Just before the test, turn the fuel screw out a decent amount. This will make it dull sounding.

Remember to turn it back to the correct position afterwards.

You didn´t hear it from me!👍

I did it at a race last year, and my original packing was 45 hours old.

It passed easily.

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Cool thanks. I'll try that if I have a problem. Not sure if it you have the same testing as we do. which is 94 db at 5000 rpm. Its a pretty good exhaust for a stock pipe dont really want to mess with it. Hopefully its raining so they cant do the test because it messes up the readings.

We have the same test, AMA and America adopted the F.I.M. sound test about 2 years ago.

94 is really 95,9 dB when rounded off upwards and 1 extra decibel is given to compensate for the testing equipment.

Do you race your 250F at 5000 RPM´s by the way?

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Cool thanks. I'll try that if I have a problem. Not sure if it you have the same testing as we do. which is 94 db at 5000 rpm. Its a pretty good exhaust for a stock pipe dont really want to mess with it. Hopefully its raining so they cant do the test because it messes up the readings.

So your doing the A4DE mike? Same here. I am fairly poistive your stock exhaust will be fine. I have been told by officials at other enduro's this year that anything stock will be fine, its the aftermarket ones they will focus more on. The KX one is designed specificaly to pass the 5000 rpm noise test and still flow really well, its been qouted by a few mags that its one of the quietest in noise tests but one of the louder ones on the track. I have also noticed that on the 2010 KX when its in neutral the timing must be retarded/changed in the CDI by the neutral switch on the gearbox, as when you click it into gear it immediately advances/picksup revs. Sounds to me like one reason this is done is to help with noise testing.

We have the same test, AMA and America adopted the F.I.M. sound test about 2 years ago.

94 is really 95,9 dB when rounded off upwards and 1 extra decibel is given to compensate for the testing equipment.

Do you race your 250F at 5000 RPM´s by the way?

Spot on. They say 94 db but there is actually a 2 db rounding up that can be used so you actually only need to pass 95,9 db 👍

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Yeah Sure any, First attemp for me so not sure about it all. Have heard they are real tough on exhaust noise. We tried to test it at work today but dont have equipment to get the rpm. good news in my DRD arrived and i will take both but run stock for the event unless it fails.

Yes the 450 are lower my mistake

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