2007 YZ 450 signs off earlier

9 replies to this topic

Posted March 28, 2010 - 09:07 PM


I've got a bone stock 2007 450. Love the bike, but it doesn't have much top end. Do any other 07 owners have the same feeling? My 06 seemed to pull quite a bit longer on the top end. Does it have to do with the silencer having a smaller diameter hole?:thumbsup::banghead:

  • Family Man

Posted March 29, 2010 - 08:17 PM


The 07 should have more top end, different cam profile.The muffler does fine in the top end. Check your jetting.


Posted March 30, 2010 - 08:24 PM


Would this indicate a lean or rich condition on top? I'm thinking lean like I'm running out of fuel on the top end?? Thanks for any comments.

  • Family Man

Posted March 30, 2010 - 09:21 PM


Is it blubering in the top end? Or popping?

  • Six5

Posted March 30, 2010 - 09:50 PM


My '07 seems fine on top, but I could use a little more grunt down low. And mine is stock except for a Zip Ty carb mod.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed

Posted March 31, 2010 - 04:20 PM


It seems like it runs fine, no blubbering or popping up high. It blubbers a lot down low. It just stops pulling sooner than my last 3 yz450's have.

  • grayracer513

Posted March 31, 2010 - 04:25 PM


You might want to check your cam timing.


Posted April 01, 2010 - 04:13 PM


Thanks for all of the advice guys, checked the valves and timing, everything looked really good. I'll try dropping a size on the main jet and see if that helps. I think I'm around a 170 at 4500 ft, probably too rich, the plug was pretty dark and wet.

  • Family Man

Posted April 01, 2010 - 05:11 PM


The plug condition generally dont mean squat on a four stroke. Try adjusting the jetting pilot circuit.

  • qwert321

Posted April 01, 2010 - 06:15 PM


160 is stock for sea level,you stated your bike is stock so you should atleast be at 160 maybe 155-158

Related Content


Should I buy this bike? help....... by Numsa Hul

Dirt Bike   General Dirt Bike Forums   What bike should I buy?
  • * * * * *
  • 10 replies

Michigan Motocross Tires by 288yz450

Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply

Megabomb Fitment by 288yz450

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply

The "going back to the other darkside" adventure... by Monk

Dirt Bike   Make / Model Specific   KTM   250/350/450/505 SX-F & XC-F (4-Strokes)
  • Hot  113 replies

James Stewart back on a YZ450F by YamaLink

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.