Yz426f being a female dog

103 replies to this topic
  • Arizo

Posted November 08, 2013 - 07:21 AM


Hey peeps, I'm new on thumper but i have been reading as guest for long time. My problem is, it almost never wanna start... This is what i did till now. New spark plug.(it sparks) Valves adjustement. Cleaned air filter. New oil filter and oil. Fuel filter installed between tank and carb. pilot jet from 52->45 Fuel screw 1,5 turns out I am really getting pissed about it because i cant find the problem. I hope you guys can help me.

Edited by Arizo, November 08, 2013 - 08:53 AM.

  • fdme

Posted November 08, 2013 - 12:22 PM


What is the history of the bike? Is it new to you? Are you familiar with the kick-starting process? Did it start up fine at one point? Was it a sudden change or gradual?

  • phil2k

Posted November 08, 2013 - 02:15 PM


I make sure I clear out the cylinder before I kick mine, pull out hot start, pull in decomp, kick 20 times, push hot start back, pull out choke, and kick it, it will start after 2nd or 3rd kick

  • Arizo

Posted November 08, 2013 - 03:06 PM


Sorry i forgot, i installed hot cam auto decompression. It starts sometimes after a half hour kicking or something. I removed decompression lever also and put a plug in. No i do not know the history from the bike and it is not new to me.

Edited by Arizo, November 08, 2013 - 03:07 PM.

  • fdme

Posted November 08, 2013 - 03:54 PM


I'm not too familiar with the auto decompression cam... But is it possible you have it installed wrong? Is the timing good?

  • Arizo

Posted November 08, 2013 - 04:09 PM


I am sure it is installed right(triple checked it) it started once and was running good, it is just the starting that is the problem

  • yellow ketchup

Posted November 08, 2013 - 04:32 PM


Check to make sure your cams are timed correctly after the install...I had a 426 and had the same problem after installing the same cam...it seemed right at first, was a pain to start so I went back through and found I was 1 tooth off

  • Arizo

Posted November 08, 2013 - 04:51 PM


Ok ill do that tomorrow, wel before the hotcam installation it was also almost impossible to start, maybe there was already some timing issue.

I reinstalled it from pictures i took before i took the cams out. There are no marks on the exhaust hotcam to allign with.

Srr for my english

  • yellow ketchup

Posted November 08, 2013 - 05:08 PM


There should be marks...usually just a little dot in the gear casting...make sure they both align in the center when the engine is at TDC

  • fdme

Posted November 08, 2013 - 05:25 PM


The yz426 cams should look like this

Attached Thumbnails

  • 1383960298766.jpg

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

Posted November 09, 2013 - 02:57 AM


This is from my yz426f

Attached Thumbnails

  • 1383994587363.jpg
  • 1383994607052.jpg
  • 1383994622608.jpg

  • grayracer513

Posted November 09, 2013 - 09:11 AM


Intake cam is a tooth advanced.

  • Arizo

Posted November 09, 2013 - 09:54 AM


Just got back in there and there are 13pin between marks, if i put the intake a tooth back it is gonna be 12pins. It needed to be 13 pins right?

  • grayracer513

Posted November 09, 2013 - 10:02 AM


Forget the tooth count.  The timing marks have to line up, not the two marks on top.  And no, if you back the the intake up until it aligns, it will be 14, not 12.


The exhaust cam was made for a 426 and not for a 450, correct?  If so, time it by the marks.

  • Arizo

Posted November 09, 2013 - 10:06 AM


Yes 14 i mean srr

yes it is for a 426.
Thx for the help i will get back into ot tomorrow.
I don't have the time now.

  • Arizo

Posted November 10, 2013 - 06:52 AM


Previous photo, the chain tensioner was off, now this is a pic while the chain tensioner is installed, looks good to me

Attached Thumbnails

  • 1384095056035.jpg

  • grayracer513

Posted November 10, 2013 - 09:00 AM


Looks OK in that one.

  • Arizo

Posted November 12, 2013 - 08:13 AM


I have reinstalled everything, checked my pilot jet it was clogged, i cleaned it and went from 45->48. Still no start.

  • Arizo

Posted November 13, 2013 - 08:38 AM


I got my carb off, the jet needle was on 5th clip i put it on 4th (din't see a single person that has it on 5th clip so).

Anything other i need to check while carb is off?

My spark plug is oily but i dont think fuel is getting in there.
Any suggestions?

  • Arizo

Posted November 13, 2013 - 02:45 PM


Nobody who can help me get this thing started?

Related Content


Michigan Motocross Tires by 288yz450

Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply

Yamaha YZ450F 2017 by Chris.GVS

Yamaha YZ450F 2017
  • * * * * *
  • 1 review
  • Last review by Tommyk_55
  • On January 15, 2017

Chubby dad, looking at bikes , First trip to the orange/black forum ! by Slow_ride

Dirt Bike   Make / Model Specific   KTM   250-530 EXC/MXC/SXC/XC-W/XCR-W (4-Strokes)
  • Hot  28 replies

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

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