popping noise after deceleration after removing air pump

8 replies to this topic
  • elm327

Posted January 23, 2006 - 06:29 PM


new wr owner, just removed air pump , used the yamaha kit, done the full mod, exhaust tip,airbox restricter, grey wire. now it pops and burbles under decelaration, followed directions, used 48 pilot,supplied needle, no other jets, air screw 2 turns out. runs good , but annoying pop , also tried 06 yz muffler and it made the super loud pop and foot long blue flames, am i too lean on main jet??? took yz muffler off as it was machine gun popping bad!! an new to 4 stokes after retiring the 90 cr500. please help!! dealer is a moron.only thing i didnt do is cut the airbox.

  • elm327

Posted January 23, 2006 - 06:31 PM


did not mention that i am in indiana , so altitude is not a problem

  • Texas4play

Posted January 23, 2006 - 06:43 PM


Decel pop is a lean condition

  • Indy_WR450

Posted January 23, 2006 - 06:46 PM


Get the JD jetting kit from the TT store and put the red needle in clip #5 or blue needle in clip #3 and 170 main. :thumbsup:
Believe it or not the needle position and taper is critical for good jetting! Get rid of that fixed needle immediately! :bonk:

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

Posted January 23, 2006 - 06:57 PM


It's gotta be the Main Jet. I agree with the 170 Main, your needle is not adjustable but that doesn't matter cuz it's fine right where it is. If that doesn't work take it over to Indys house...... :thumbsup:

  • obermeyer

Posted January 24, 2006 - 10:46 AM


He Has Removed The Fixed Needle And Replaced With Adjustable Needle.

  • elm327

Posted January 25, 2006 - 09:28 PM


problem solved!!!!!!! 170 main jet and msr easy adjustable air screw 2 3/4 turns out!!!

  • skidxr

Posted January 28, 2006 - 04:32 PM


do you need to remove the carb to do the jeting?

  • rich1167

Posted January 28, 2006 - 04:36 PM


You can get to the main with the carb in the bike. But the rest of them you need to remove it. I guess you may be able to replace the pilot, but it would be difficult with it in the bike.


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.