450 starting

6 replies to this topic
  • zachrider

Posted December 16, 2006 - 08:29 PM


Hey everyone, the names Zach, been skimming over the forums, and thought id join in. I ride a 2004 yz450 and live in San Diego, Cal.:devil:

anyways, i changed the oil in the 2004 yz450f i recently took ownership of, and its hard to start now. i used the recommended oil in the manual, put a little more then a full quart in, and it starts, but it takes a lot more kicks than before i changed the oil. it starts, it runs, not as good as before, but sometimes dies when given throttle, after warming it up for a minute or so. Its probably a minor thing, but i cant figure it out. i tried to get the plug out to check it, but my spark plug wrench doesn't reach long enough. i dont give it any gas when starting. im just wondering if anyone knows how i can fix this to get it back to how it started before(1-2 kicks), has anyone had this problem after changing oil? i didnt take out the plug and kick it a few times like some people say to, so maybe thats it. im knew to the fourstroke stuff, let alone motorcycles in general(been riding 4 years, know general two stroke maintenance) so any advice is greatly appreciated.:thumbsup:

thanks much

  • grayracer513

Posted December 16, 2006 - 08:52 PM


My own '03 450 has never started well unless the throttle was cracked slightly open when cold starting (choke on, 2-3 twists, push through once, crack the throttle and kick. normally takes no more than two, usually one)

Get a plug wrench that works (Motion Pro makes a handy one). Your problem, if not relieved by a change in technique, could be the plug. Try a new one. Also, be sure your idle fuel screw is trimmed right.

  • zachrider

Posted December 16, 2006 - 08:55 PM


thanks for the imput. can you tell me what you mean by the idle fuel screw being "trimmed right"?

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  • grayracer513

Posted December 16, 2006 - 09:01 PM


This info is for a 250F, but the procedure is exactly the same. You will very soon find out why people like the extended idle fuel screws.


  • zachrider

Posted December 16, 2006 - 09:17 PM


awesome. I think my problem was messing around with the idle adjustment knob too much when the engine wasn't warmed up, and now its idle isn't right. Ill give this fuel screw a try, and see how it turns out, thanks again.

  • rexbond007

Posted December 17, 2006 - 09:39 AM


Another reason your bike may be hard to start, your valves may be due for an adjustment?

  • zachrider

Posted December 17, 2006 - 10:58 AM


the guy i bought it from had them adjusted when i bought it, which was a couple months ago, and before i changed the oil, it started in 1 kick most of the time, so i dont think its the valves, but you may be right.

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