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bigwake

that gurgling..sputtors..??bakfires?

21 posts in this topic

i went for my first ride on my 03 yz450f..couldn't have been more pleased with this thing!..anyone know what that sputter/backfire/gurgling noise is when you let off at high speeds? just curious.. thanx-josh

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its normal u can hear it on all 4 stokes and more on harleys its just when the bike reves down

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from what i gather that decel popping is supposed to be minimal but iv spent all weekend playing with jetting and cant get it to go away......

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i went for my first ride on my 03 yz450f..couldn't have been more pleased with this thing!..anyone know what that sputter/backfire/gurgling noise is when you let off at high speeds? just curious.. thanx-josh

I usually find it's a lean pilot jet and/or a air leak in the header pipe.

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anyone know what that sputter/backfire/gurgling noise is when you let off at high speeds? just curious.. thanx-josh

It's the unburnt fuel in the exhaust pipe igniting due to the heat when air rushes in(supplying oxygen) through the end of the pipe. It can be worse if the pilot circuit is lean. You might want to read this, http://www.motocrossactionmag.com/me2/dirmod.asp?sid=&nm=&type=news&mod=News&mid=9A02E3B96F2A415ABC72CB5F516B4C10&tier=3&nid=6E5BCFD99FD242B28032722A4D5D52E3 and grab an (easy)adjustable fuel screw from the TT shop, they're $20. If you get one, make sure it's for your bike(year model). I think there's only two different fuel screws sold by Zip-ty.

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I usually find it's a lean pilot jet and/or a air leak in the header pipe.

100% totally agree with fine tuning the fuelscrew....(buy one u will need it)...my 03 does not do this anymore.....:thumbsup:

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but what happens if i don't buy one??..is it really a NEED or is it just so you don't hear that noise anymore...because i think the noise is kinda cool..haha

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Be careful which adjustable fuel screw you buy, I have seen one that was

just enough different than the original, it did not fit the hole it is designed

to go in to. I'm haven't check all the different ones to know which one to recommend.

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The fuel screw can make a big difference on how the bike pulls from idle to a quarter throttle or so. They're worth using simply for the fact that as the temperature, Humidity/Altitude change, you can fine tune the carb easily.

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but what happens if i don't buy one??..is it really a NEED or is it just so you don't hear that noise anymore...because i think the noise is kinda cool..haha

They're not noise reducers, they're for tuning your bike!:D If you like the noise, you'll still hear it when going from fully open throttle to fully closed, even when your pilot circuit is tuned.:thumbsup:

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