engine making wierd noises? :S


9 replies to this topic
  • corndogg

Posted June 21, 2011 - 06:57 AM

#1

hey, so i bought a 2004 yz 450 the bike was stock when i got it, so i put a fmf pipe on it and new air intake. the bike was runnning lean the header was glowing red hot jus after a cold start. so i re jetted the bike and the took it for a ride and the bike started making a really loud vibration noise coming from the engine about 45 min into the ride. i cannot figure out what is going on. perhaps the valves need to be done again? the sound to me is a vibration coming from the engine or something slapping on something else.....any sugestions?

thanks

  • ninjaman123

Posted June 21, 2011 - 10:44 AM

#2

Yamaha makes some wierd slapping noises in their four strokes sometimes. I have a Raptor 660 that does that and it is built to the hilt i took it in and they said its normal. Its your valves opening and closing extremely fast. If soemthing happens to it get kibblewhite titanium valves. And since it is a 450 it will be louder than most so dont worry about it.

  • dgcars

Posted June 21, 2011 - 10:57 AM

#3

Search the FAQ with regards to your header. Don't re-jet.

  • grayracer513

Posted June 21, 2011 - 11:15 AM

#4

Have it looked at or compare it with a couple of similar bikes to see if the noise is normal or not.

  • corndogg

Posted June 21, 2011 - 02:12 PM

#5

should the header be red hot shortly after start up? only ideling for a minute? ive never had that happen before

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  • corndogg

Posted June 21, 2011 - 02:46 PM

#6

and by red hot i mean glowing red. even had like sparks come off the exhaust.

  • grayracer513

Posted June 21, 2011 - 03:14 PM

#7

Normal would be red heat, easily visible in twilight, or a garage lit by two 100 watt bulbs after a minute to a minute and a half. Frankly, running too rich is more apt to cause it than too lean. More prone to it with the choke on.

  • corndogg

Posted June 21, 2011 - 03:40 PM

#8

thanks for the input. appreciated. this bike is jus drivin me nuts!! the reason im so paranoid about it is because my last bike 3 times even after yamaha mechanics rebuilt the motor.

  • corndogg

Posted June 22, 2011 - 03:08 PM

#9

its a 2004 yz 450 its all stock except for a k&N air filter and a fmf powerbomb header with a power core exhaust where i live is 76.2 m above sea level. any jetting suggestions would make my life allot easir.

  • grayracer513

Posted June 22, 2011 - 04:18 PM

#10

its a 2004 yz 450 its all stock except for a k&N air filter and a fmf powerbomb header with a power core exhaust where i live is 76.2 m above sea level. any jetting suggestions would make my life allot easir.


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