YZ450F 2007 Hard to start

2 replies to this topic
  • Duvaly

Posted November 30, 2008 - 01:59 AM


My YZ450F 2007 is difficult to kick start and it only gets worst when the engine is hot. On top of that, the engine gets extremely stubborn, needing well over 15 strokes to get the engine running (with or without using the hot start lever). When the engine is running, it works fine. The piston, rings and cylindre were recently changed and the bike has been driven about 4-5 hours since then. Grateful for any good advice. Thanks.

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

Posted November 30, 2008 - 04:43 AM


Common problem.
You need to adjust the valves

There wll be one out of wack
Kinda hard to do, you need to have good feel and be carfull not to force the feeler gauge in because of the light spring preasure.

  • qwik12beat

Posted November 30, 2008 - 09:02 AM


you need to have good feel and be carfull not to force the feeler gauge in because of the light spring preasure.

+1. Good call. The first time i shimmed my valves i couldnt believe how soft the springs were. Kinda makes me wanna get some kibblewhite springs. If your valves happen to be in spec,then i would check your jetting. I always turn the gas on,wait 1 min,choke it,give the throttle one quick twist, and she fires on the first kick.

Related Content


Yamaha YZ450F 2017 by Chris.GVS

Yamaha YZ450F 2017
  • - - - - -
  • 0 reviews

Megabomb Fitment by 288yz450

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

First Hare scramble tips by dhend8

Dirt Bike   General Dirt Bike Forums   General Dirt Bike Discussion
  • Hot  33 replies

2016 YZ450 by CaptainKnobby

Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies

yz250x vs 450 4t comparisons (preferably desert riding) needed by JakeNorthrupYZ450F

Dirt Bike   Make / Model Specific   Yamaha   Yamaha 2-Stroke
  • 9 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.