yz450f help????


37 replies to this topic
  • grayracer513

Posted November 23, 2009 - 08:40 AM

#21

You can verify the idle timing with a timing light. See your manual.

  • tech24

Posted November 23, 2009 - 08:53 AM

#22

huh, couldn't find it in there, ill look again.

  • tech24

Posted November 23, 2009 - 08:59 AM

#23

guess I had my head up my butt again on sat. I just found it, don't know if it will tell me what I need to see since it idles good buy its worth checking

  • tech24

Posted November 27, 2009 - 02:18 PM

#24

Well just replaced cdi and coil with a used one and well guess it was a waste of 60 bucks. Back to the drawing board. Guess I'll go over the harness real good and check grounds. Any more input would be greatly appreciated.

  • tech24

Posted December 03, 2009 - 01:12 PM

#25

well at the risk of talking to myself...I have gone over this bike head to toe...and found nothing so i guess Im going back into the carb...must be the smallest damn piece of dirt

  • tech24

Posted December 04, 2009 - 02:24 PM

#26

anyone know the symptoms of a worn out wear plate. I got a good bit of wear on bottom corner? I dont think its my problem since it ran fine until I parked it but I don't have time to order one cause I need my bike. Ill be soakin this damn carb tomorrow so hopefully..........:banghead:

  • ringet

Posted March 03, 2010 - 08:36 AM

#27

Hi tech24, did you end up finding the problem? I am having the same problem with an 07 yz 450. it started and idled but if i touched the throtle the bike would pop miss throw flames and sparkes out the back. i have done everything i can think of new plug, confirmed cam timing, check valve clearances, compression seem normal. ran fine a month ago but now i can't even get it fired up. i kick i and it backfires or blows a big soft flame out the pipe. checked kill switch and cleaned the carb. this has got me stumped. i also have a yz 444 and i started that the same day and it ran like crap and was poping and missing but i reved it to the limiter a couple times and it cleared right up and ran perfectly. i'm seriously out of ideas at this point. can you help me or are you still inthe same boat?

  • ringet

Posted March 03, 2010 - 01:34 PM

#28

i got it running took everything apart again assembled it all to spec kicked it it was backfiring them it fired so i reved it to the limiter a couple times and it completely cleared up. not a clue what changed but it's running again

  • tech24

Posted March 05, 2010 - 06:20 AM

#29

thats good news but no I never fixed the problem with mine. After having the carb apart several times I got fed up. I decided to completely rebuild from the ground up. I tossed the FCR for an edelbrock. Im a few weeks away from a rollin chasis with fresh powder coat, all new bearings, tires, pc triple clamps, FC suspension, and scotts stabilizer. I had a valve job and putting a new top end in, all black plastic with custome grafix, new exhaust and whatever else I can dump money into...lol.

Hopefully it runs well when done. Im pretty sure it was a carb issue.

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  • grayracer513

Posted March 05, 2010 - 07:47 AM

#30

I tossed the FCR for an edelbrock.

That's a step backward.

  • tech24

Posted March 05, 2010 - 08:45 AM

#31

That's a step backward.


Yeah it probly is but the fcr pissed me off so I figured I'd give it a try. I don't mind a slight performance loss. If its a pile then I'll toss it or sell it on ebay.

  • Frank_z28

Posted March 05, 2010 - 09:20 AM

#32

I had similar problem/symptom on my yz250 2 stroke. I did like you, carb, compression etc..... i finaly discovered that the crank bearing were shot so the timing on the flywheel would be off when i rev it...

  • tech24

Posted March 05, 2010 - 10:13 AM

#33

thats interesting, I checked timing with a light and when I could get rpms up it was fine so I guess we'll see.

  • Frank_z28

Posted March 05, 2010 - 10:44 AM

#34

juste remove the cover on the magneto side and see if their is chaffing mark on the flyweel or play on the crank

  • grayracer513

Posted March 05, 2010 - 11:08 AM

#35

Yeah it probly is but the fcr pissed me off so I figured I'd give it a try. I don't mind a slight performance loss. If its a pile then I'll toss it or sell it on ebay.

I just sold an '06 YZ450 carb to another member here who used it to replace an Edelbrock on a 426. He said the bike never ran so good. The carb was 100% as issued stock, too.

  • tech24

Posted March 05, 2010 - 11:24 AM

#36

Im putting a flywheel weight and cover on so I'll take a look at her then

  • ringet

Posted March 07, 2010 - 03:29 PM

#37

where is the carb now? do you still have it

  • tech24

Posted March 08, 2010 - 05:35 AM

#38

I just sold an '06 YZ450 carb to another member here who used it to replace an Edelbrock on a 426. He said the bike never ran so good. The carb was 100% as issued stock, too.


Damnit don't discourage me...lol. I've talked to a few people on here that have eddies and they are happy. I always gotta learn my own lessons. Hpefully she runs ok.

where is the carb now? do you still have it


I still have it, probly going on drag quad after some repair and mods.





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