Low Speed Bog

2 replies to this topic
  • finglan

Posted February 09, 2001 - 02:16 PM


The weather broke enough to allow me to ride my WR426 around the yard a little. I noticed that while at low speed in first or second gear if I gave a quick twist of the throttle the bike would bog right out for a second. Do I need to adjust the pilot screw?
This is my first ride on the bike. I added a fuel filter that slid into the fuel line hence it had a slightly smaller opening than the stock fuel line. I also installed a YZ throttle stop and routed the carb vent lines up near the airbox. Could any of these mods. cause the low speed bog or is it just the pilot screw. I did read on the YZ fourm that this is a common problem w/the YZs. Most owners have just learned to roll on the throttle smoothly at lower speeds instead of snaping it.

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  • MN_Kevin

Posted February 09, 2001 - 04:03 PM


Pre 2001 problems, I believe, have been traced to the accelerator pump. Your fuel screw very easily could be your problem, but I am not Clark or James.

  • James_Dean

Posted February 09, 2001 - 08:11 PM


Try the pilot screw by turning it out 1/4 turn at a time (richer is out) to see if it helps. Be sure to check where it is to start with so you can always go back if you need to.

Do not go out past 3 turns. At 3 turns get a bigger pilot jet (45) and do the same process starting at 1 turn.

My WR400 was set at 3 1/2 turns with a #42 pilot by the previous owner.



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