Yz426 wont run unless choke is out! HELP!

3 replies to this topic
  • ThorManMitch

Posted May 09, 2015 - 08:20 AM


I just installed a quickshot 3 acc. pump cover on a 2002 yamaha yz426.  I started it up and it was running funky and popping, i pulled the choke out and it ran fine.  Now it wont run unless the choke is out, but it runs great with the choke out.  Do i need to jet up due to this upgrade? i put an FMF powercore 4 on it at the same time as the quickshot, some much needed advice would be awesome, PLEASE HELP!

  • Baldwin

Posted May 09, 2015 - 02:30 PM


Sounds like it's running lean. I would recommend cleaning or replacing your jets. If that doesn't work maybe try up sizing them. Not sure about the quickshot so maybe that has something to do with it.

Was it sitting for a while before you did the mods?

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • grayracer513

Posted May 10, 2015 - 03:42 PM


The pilot jet is the likely culprit.

  • 4racx3

Posted May 10, 2015 - 06:01 PM


Just don't run it too hard with the choke out, I believe the bike runs hotter with it out and I was riding my rmz250 one day with the same problem as yours and the pipe started to glow orange, did some research and believe it was the choke being on. Lol

Related Content


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.