yet another wr450 jetting problem? Help

24 replies to this topic
  • coxey2

Posted May 30, 2011 - 04:28 PM


Sarcastic little **** aren't you?

Hey guys no need to bicker; thanks for all of the support! I would like to just take off the bowl if possible? Can it be done? :smirk:

  • Just_a_trail_rider

Posted May 30, 2011 - 04:56 PM


I give up. O7 wr450 with the bogg 1/4 to 1/2 throttle. I have been chasing the problem for a month now. It had a 162 main, 68 pilot, 70 air jet and did not check the leak jet yet. I did change to a 168, and did the oring mod and put two shims under the stock non adjustabe needle. It seems to have lost power and the bogg got a little better. ANy ideas, I am at 500-1000 ft at sea level. :smirk:

Boy, it sure seems like your jetting is way, way off.

For 3000 feet where I normally ride, I run a 48 pilot and a 168 main. But I live at sea level and it starts up and runs good when I open up the fuel screw a bit. I am assuming that you've opened up your exhaust like you should have.

I had a bog right up until I swapped out the leak jet to a smaller size.

Read the jetting guide sticky and the one that talks about how to eliminate the bog. Its at the top of the forum.

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  • William1

Posted May 30, 2011 - 04:58 PM


I responded to your new thread.

  • coxey2

Posted May 31, 2011 - 08:48 AM


I responded to your new thread.

thanks guys; I read how to eliminate the bogg, Sounds like the leak jet is the main problem here. WIll a smaller pilot jet make it quit back firing on decelleration? thanks

  • William1

Posted May 31, 2011 - 09:05 AM


Usually, the leak jet and the AP timing take care of the bog with the oring/wire/or spring on the linkage. Read the sticky I made at the top of the forum.

As far as decel popping, smaller pilot would make it worse and... that is not what a pilot is for. The pilot jet, in conjunction with the fuel screw is for idle only. If you richen the circuit to reduce/eliminate decel popping, you will make hot starts near impossible because the idle circuit is too rich.
On your bike, you have an ACV (Automatic Coast Valve) Its' purpose is to add fuel during decel to deal with the popping. So first, ensure it is working properly. Spring serviceable, diaphragm in good condition, nothing clogged. Also check the header to head connection and midpipe connection. Hold your hand (with a thick rag) over the exhaust pipe and listen for the hiss of a leak. If you have an aftermarket open pipe, fresh packing will help but open pipes promote decel pops and you may have to live with it.


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