Engine problems

4 replies to this topic
  • IrideWR

Posted November 07, 2010 - 11:17 AM


I have not been able to get help in the quad treads:bonk: so i thought i would ask hear do to the great help Iv gotten for my 07 wr450 :p. I have a 2006 Raptor 350 for my wife, last year it started not to run at idle I figured a dirty carb was the reason and turned the idle speed up of the time being. During the off season I cleaned the carb and put in a jet kit the problem was the same and I noticed a back fire pop but it was in the intake, I put the carb back to stock jetting and cleand it thourly agin to start from stock and the problem still exist, and it is this when its cold I have to leave the chock cracked and turn up the idle speed, and at a reasonable idle it pops in the intake, after a hour or too of riding the idle speed is to hi so I turn off the choke and bring the speed down but it still pops at a good idle speed. I thank it might be timing or valves what are your suggestions?


Posted November 07, 2010 - 12:17 PM


I don't think it's timing or valves unless the cams jumped a tooth but doubtful. A bad valve usually results in extreme difficulty starting particularly cold but not backfiring. Everything your describing is typically lean jetting on the pilot circuit caused by either a blocked passage or jet. Also not sure what carb you have but if it's an fcr make sure the slide plate is put in correctly. It's possible to put it in upside down which results in symptoms much like you're describing.

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  • Krannie McKranface

Posted November 07, 2010 - 12:43 PM


Define 'cleaned carb'............it sounds like the pilot passage is still dirty.

Hot start plunger?
Hot start cable hung up?
Torn/leaking airboot?

  • 2in2out

Posted November 07, 2010 - 06:42 PM


Check Bluetraxx.com Raptor 350 threads and do a search for the rev limiter mod. This is a common problem and it is due to the rev limiter. Behind the front cowling above the left headlight there is a black plug(I think. Been a long time since I read about it) with 2 wires to it. Unplug, seal with silicone tape or heat shrink.

Next research the neutral switch mod and reverse rev limiter mod. Should get you all fixed up.

  • IrideWR

Posted November 08, 2010 - 05:31 PM


Cleaning the carb consist of puling every jet out and cleaning them and all the passages also the needle and seat, the air fuel screw and the slide and needle every than there is to clean got cleaned twice with carb clean. Every thing in this carb fits back one way. Ill research the help iv got so far and let you know if I get it.


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