missing wr450f

13 replies to this topic
  • bucko13

Posted October 16, 2009 - 01:39 AM


my 2006 wr450f misses every now and then when accelerating but this only happens sometimes and the bike runs perfectly appart from that. it has plenty of power runs smooth (appart from when this happens) and is responsive. i thought the jetting may be lean but i dont know can anyone help please?

  • William1

Posted October 16, 2009 - 02:29 AM


A miss is from being rich, not lean. If it were lean, it would be 'dry/flat' and just not accelerate at all. Has it always been this way or is is this a new issue?

  • Ron Hamp

Posted October 16, 2009 - 04:46 AM


Does it only seem to do it in 1 certain gear like 3rd or 4th i experienced the same problem on 2 yamahas it sounds lke a engine miss when its actually the transmision jumping in and out of gear.

  • bucko13

Posted October 18, 2009 - 11:21 PM


No its definately not the transmition its definately in the engine

  • bucko13

Posted October 18, 2009 - 11:24 PM


its always done it but lately it seems to be doing it more. i will try leaning out the jetting a bit and see if that helps at all, thanks.

  • ww44wrf450f

Posted October 24, 2009 - 08:34 PM


Did you get the miss out, try a new plug--had that happen when I left the choke on too long (( forgot)):bonk:

  • unclemd

Posted October 25, 2009 - 12:52 PM


My bike has a little miss that happens usually 1-2 twice when using the bike on the street in 1st-2nd gear on soft acceleration. It's like a couple little pops that then goes away. This doesn't happen all the time and i'm new to the bike. Bought it second hand with the AIS GYTR kit pulled and grey wire mode complete. Pea Shooter exhaust baffle is also pulled.

Is this the same type of miss you are experiencing?

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  • thatraptorguy

Posted October 25, 2009 - 01:56 PM


try dropping the clip on your needle 1 position thats what did it for mine

  • Strattos

Posted October 25, 2009 - 03:08 PM


I had similar problems on my old bike, an 02 WR426. See below if it's any help...


  • unclemd

Posted October 25, 2009 - 04:20 PM


Thanks for the response i'll try both things but when you mean lower the clip one notch on the needle you mean lower the clip which raises the needle to run richer?

  • bucko13

Posted October 26, 2009 - 01:30 AM


i didn't lean the jetting out but instead i derestricted the airbox and put a unifilter pro comp 2 in to get it breathing good and this seemed to help a lot but it didn't completely solve it it still misses around once every ride but im quite happy with it. i pulled the spark plug out and it looks good so the jetting can't be that far out. i will get a new plug though as this one has done around 100 hours. apart from that the bike is running awsome since i did the mods and i have racked up a heap more kays on it. thanks for the help

  • bucko13

Posted October 26, 2009 - 01:40 AM


i didn't lean out jetting instead i derestricted the airbox and this helped a lot but the bike still misses around once a ride when i accelerate . its fine at constant throttle just when accelerating under a bit of load. i will replace the spark plug as well because this one has done around 100hrs since i changed it last. the bike definately doesnt do it as much and it has eyewatering power and runs very smoothly. thanks for the help.

  • William1

Posted October 26, 2009 - 05:54 AM


Fresh plug is a must. Being it is better, I suggest still leaning it out further. The opening of the airbox mostly affects WOT, not mid RPM. Move the needle clip two positions closer to the top/flat.

BTW, what needle are you using?

  • bucko13

Posted October 30, 2009 - 01:09 PM


ok will try leaning it out further. i am using the needle that i got with the bike but i think the dealer replaced the stock one with something different because i have been told that 2006 wr450's come with a none adjustable needle. i have had a look at mine and it is definately adjustable. don't know what size it is though. thanks.


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