Exhaust noise

[400exrules]

I just got my 400ex and ive never ridden a quad that had an aftermarket performance exhaust, and i have an HMF pipe. And when i rev up their is this kind of loud whipping noise of air flow coming from my exhaust pipe. Its almost a popping noise, but not quite, When you let off the throttle real fast it just sounds like aton of air is flowin through and makin a weird noise. Its probably normal, but i was just wondering if its normal to hear the loud whipping noise of the air or wutever, when i let off the throttle. Mind you, it makes this noise when im in nuetral and rev it up or when i pull in the clutch while riding and rev up, and suddenly let off the gas. And its not a random popping noise when i let off, its kinda a constant one until the rpms go back down....kinda like , *bup bup bup bup bup*

I dont know if my jetting is off, or if this is normal? The guy said he got dynojets or something and that he jetted it to the pipe

Sorry if that doesnt make any sense, its kinda hard to explain

[RiderTRX400ex]

i think i know what your talking about? it sounds like your talking about the air from the exhaust cutting through the air around you. If thats it, it should be normal... just part of the exhaust.... do u have a spark arrester in it? a screen..... maybe thats it..

[HondaRacing23]

is it kinda of a whistleing sound while it is idles down. my HMF does that.

[400exrules]

no it doesnt whistle at idle. And the noise is very obvious and somewhat loud i guess, right now, because i have no quiet core or spark arrestor in.

But it seems to dampen it a bit, or make it less noticable with the quiet core in

[wanta450]

yeah youll normally hear a bup bup bup from an aftermarket exhaust

my neighbors 450r did the same thing after he had a new cam put in, then a few days later his motor grenaded. Not saying thattl happen to u, just a warning that its a possibility

nvm, that was a different noise, sorry to scare you haha check to see if theres seals where the header meets the motor and where the header goes into the silencer.

[2001400exrider]

Originally posted by aLLoY MX 428
my neighbors 450r did the same thing after he had a new cam put in, then a few days later his motor grenaded. Not saying thattl happen to u, just a warning that its a possibility

lol...dont scare the kid... hey man i just put my HMF full system on tonight and fired it up! yea mine sounds like ur describing i think and its normal. VERY LOUD! kinda higher pitch then i thoguht it would be BUT IT LOVE IT:D :D :D 100000000000 times better then stock:devil:

[LTZ400rider]

they way ur describing it id think it was ur intake if u have a open lid

[400exrules]

Originally posted by 2001400exrider
lol...dont scare the kid... hey man i just put my HMF full system on tonight and fired it up! yea mine sounds like ur describing i think and its normal. VERY LOUD! kinda higher pitch then i thoguht it would be BUT IT LOVE IT:D :D :D 100000000000 times better then stock:devil:

yah i love how mine sounds without the quiet core at idle and puttin around at low rpm's