popping at 1/4 throttle


7 replies to this topic
  • yzf450jack

Posted September 30, 2004 - 05:51 PM

#1

My YZ450/470 is popping in neutral at 1/4 throttle tryed a bigger pilot jet 45 changes nothing 48 changes nothing I put an edelbrock carb on same popping it idles good starts on first kick but at 1/4 throttle it's popping and the pipe starts glowing :cry: so the carb is not the problem So Anybody know whats up.........

  • Joe_Jet

Posted September 30, 2004 - 06:48 PM

#2

Possible exhaust leak

  • yzf450jack

Posted September 30, 2004 - 07:47 PM

#3

Nope not exhaust leak not in carburetor i tryed a differant carb still popping like it's very lean.I can make it rich and still popping you think the exhaust valves going bad :cry:

  • skthom2320

Posted September 30, 2004 - 08:28 PM

#4

My YZ450/470 is popping in neutral at 1/4 throttle tryed a bigger pilot jet 45 changes nothing 48 changes nothing I put an edelbrock carb on same popping it idles good starts on first kick but at 1/4 throttle it's popping and the pipe starts glowing :cry: so the carb is not the problem So Anybody know whats up.........


The pilot jet doesn't affect 1/4 throttle opening - that's the needle. Go down one clip position...

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  • YZ250F_Rider

Posted October 01, 2004 - 02:49 AM

#5

if both the stock carb and the edelbrock pop at the same place then it's not going to be the stock needle thats causing the popping.

Assuming you dont have leaks, check the fuel, the cdi, the tps, and the stator. It's all you have left. :cry:

  • motocrosschump

Posted October 01, 2004 - 05:21 AM

#6

mine a long time ago, had the same problem, my solution with to file down the stopper of the carb clamp, so it sealed better, pop went away.

  • Chris_from_Oz

Posted October 01, 2004 - 05:39 AM

#7

Have you checked your inlet manifold for leaks. I split mine in two places on my 426, but as someone else mentioned, the clamp spacers can restrict the proper clamping force required to effectively seal the manifold to the head and/or carb'. Worth a look..... :cry:

  • yzf450jack

Posted October 05, 2004 - 05:13 PM

#8

Yes checked intake for leak im good If you cruz at 1/8 throttle with no load on the motor it don't run smooth but runs hard everyware else :cry:





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