wr 400 hard to start

6 replies to this topic
  • clodeb

Posted February 11, 2012 - 09:17 PM


I just change the exhaust cam for a Hotcam with au-decomp,everything is set ok and correct valves clearances. I also installed a yz450 '08 carb. Now with my new cam i have to get WFO trottle to get it running...after that it run nice and smooth,nice idlle. If i shut it off,it start on the first kick. But cold it is a pain in the %@#**!*( should i go with a leaner pilot jet!!!

  • cjard

Posted February 12, 2012 - 02:16 AM


Can you describe every step in your cold starting routine that doesn't work? Literally every action you take.. Throttle, choke, kicking how many times etc

  • clodeb

Posted February 12, 2012 - 08:06 AM


First i just installed i a few days ago (exhaust cam) so, i first pull the choke and crank a few times...nothing then twist the throttle 2 times and try it with the choke and then close it...still nothing.............after that i close the choke and hold the throttle open and crank it a few times and it start.It is in my garage but outside it is -15cel so not warm like summer here!!

After it get warm it seem to run well with a nice idle.Once warm it start back on the first kick with no gas.I dont remember in the yz carb if it's a 45 or 48 pilot.it's got an adjustable gold screw underneath the bowl .

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  • clodeb

Posted February 12, 2012 - 10:06 AM


went again to start it this morning and notice some gas dripping from the carb hose to the floor...again hard to start,choke no choke,choke again,twist of the trottle a few time and vroom it start and run fine after!!!!!!!!!!! i think i have an issue of too much gas at start up either from too rich or too high float.......any clue

  • cjard

Posted February 14, 2012 - 07:30 AM


Did you change the jets in the carb for the jets out of your old '400 carb? After you've had it running for a while, take the plug out and have a look; what's it look like?

  • Snarfie

Posted February 14, 2012 - 09:12 AM


You cant just toss a new carb on the bike and expect it to be good man, you need to open that thing up, and make sure it doesnt have a clogged pilot [which is VERY common] and will make starting it pretty much impossible.

Also, if its that cold out, and its not jetted properly for the weather, that will make starting MUCH more difficult than it needs to be, even if the pilot, or some other jet, isnt clogged up.

  • clodeb

Posted February 19, 2012 - 06:19 PM


Well i put that new carb in septembre with no mods just to see if it runs great and it did!! I just bought a leaner pilot jet that i will install the week end and will se what next i have toadjust

It seem that after my cam change the starting routine is different...i may just have to adapt. Maybe my float is too high cause it smell gas a lot


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