2005 yz450f hard to start new motor

3 replies to this topic
  • jeredlee

Posted October 30, 2015 - 09:42 PM


I just put a whole new top end in my. Piston , Sleeve and had the head done. Put it all back together got it started after about 100 kicks. Know I can't get it start. Rebuilt the carb and put a Jd jetting kit in and still same thing nothing only pops. Any ideas where to start?

  • Dexter42

Posted October 31, 2015 - 08:01 AM


Fuel screw out two turns, check for spark(visually), maybe turn idle up some. No need to kick a bike 100 times, if it doesn't start within 10 max I'd say then stop and figure out what's going on. Also double check valves, timing marks.

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

Posted October 31, 2015 - 08:44 AM


Ok thanks. Ya I'm going to back though and just check everything. Going to pull the carb back apart. Carb is leaking out of the accelerator pump it does pop and have had it running. But with all new parts it should fire right up.

  • jeredlee

Posted October 31, 2015 - 03:24 PM


Went back though and checked everything even changed timing 180 degrees . Installed new diaphragm and oil rings in accelerator pump . But still no start the pipe gets hot and the back pops but that's it. Had the bike running after the rebuild and ran fine any help where to look next would be awesome thanks.

Related Content


100 hrs on 2014 yz450f, shim valves or replace them? by ttr230rider6

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • Hot  79 replies
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info

  • 0 replies

Thinking about Yamaha 250... by Arctic Pride

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  491 replies

Help with 2000 yz426 by weekend woods racer

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • Hot  36 replies

First Hare scramble tips by dhend8

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