YZ426F- STILL a sonofagun to start

22 replies to this topic
  • mikewrf18

Posted September 14, 2011 - 06:06 AM


Yeah, I was gonna mention the valve clearances also. I always have used the EXACT method you described in the OP and my bike always started 1-2 kicks.

If any of my idiot friends decided to hop on my bike, they always gave it throttle, and completely pissed me off, because that usually meant that I had to change the plug. That accelerator pump (even with the BK mod) would foul the plug immediately.

Oh, and I don't think you want to go for a crazy, hard, kick. Just nice and smooth all the way to the bottom, with some steady force behind it....

My 02' yz250f had the same symptoms until I reshimmed the valves. If it hasn't been done, it's way, way overdue. And I also used to give mine a couple blips of the throttle If it's cold, and hasn't been started for awhile. In fact, I believe the factory manual states to do it in cold weather conditions. I'll have to check, before I put my foot in my mouth though! :)

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • mikewrf18

Posted September 14, 2011 - 06:19 AM


Here it is in the Yamaha Factory Manual for anyone who cares: This is out of the manual for the 01' yz250f and the 01'yz426f.

Starting a cold engine
Air temperature = less than
5 °C (41 °F)
Throttle Operation
Open 3
or 4 times
Cold Start
Hot Start
*Operate Throttle before starting

On page 60, (section 1-15)

  • grayracer513

Posted September 14, 2011 - 06:39 AM


Oh, and I don't think you want to go for a crazy, hard, kick. Just nice and smooth all the way to the bottom, with some steady force behind it....

If you stage the kick start the way Dr. D and I explained it, that's true, because you basically just have to push it over the top and it will start. If you do it the old school way, you will have to apply enough force to drive it through the next compression stroke, which is not an easy thing.

BTW, the bit about twisting the throttle is to prime a COLD engine, and should not be used when the engine is warmed up or hotter.

Related Content


2016 YZ450 by CaptainKnobby

Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies

Yamaha YZ450F 2017 by Chris.GVS

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

Michigan Motocross Tires by 288yz450

Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply

James Stewart back on a YZ450F by YamaLink

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 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.