07 yz450f


17 replies to this topic
  • urgreathero

Posted June 01, 2008 - 02:15 PM

#1

i have an 07 yz 450f
ran fine
let it sit for a week but now wont fire, changed spark plug, checked carb and everything seams fine, seams like its getten compression
just wont start
ne ideas?

  • Kent Rathgeber

Posted June 01, 2008 - 02:22 PM

#2

Check your air filter and put fresh gas in it. That should help.

  • urgreathero

Posted June 01, 2008 - 02:37 PM

#3

that was already changed too
and i only run premium in it
oh an dit has fresh oil and oil filter
ne other ideas?

  • BergArabia

Posted June 02, 2008 - 04:52 AM

#4

I let my YZ450 sit for 2 months while I rode around on my CRF.
I drained the fuel from carb and tank.
Filled her up and no way I could get it started.
Then I opened the carb drain again. closed it. twisted the throttle and hey presto fired right up.
Go figure..

  • urgreathero

Posted June 02, 2008 - 02:36 PM

#5

ya its not carb though everything worken correctly
its got compression
jsut no will to fire,
im about dun wit dese four strokes
next chance i get
ima sell the ****er n got back to 2 strokes
i have nutthen but problems wit this damn thing

  • Drew778

Posted June 02, 2008 - 07:22 PM

#6

Does it try to start?

My '07 sits for a week or two all the time, I try with the choke then without and it starts up within 5-7 kicks.

It starts way easier than my '05 RM Z450 did, even after adding a JD jet kit and adjust the air screw.

  • Dicko187

Posted June 03, 2008 - 01:15 AM

#7

i had the same problem with my 450 last year when i first broke it in.

get the valve clearence checked out...that seems to be one of the most common things that stop a brand new yami 450 from starting just after break in from my experiences.

  • urgreathero

Posted June 03, 2008 - 02:35 AM

#8

all the shops r backed up for weeks around here
seein how race season just started n all
but i dont think its valves
it has all the compression in the world
just doesnt wanna fire

  • mxracer206

Posted June 03, 2008 - 04:41 AM

#9

When you say does not fire, do you mean it will not start or you are looking at the spark plug and have no spark. If you have no spark then see if you can borrow a coil and CDI box from someone and re-test. These are easy enough to change out. If this does not cure the problem I have seen a few stators fail on YZ-450's so you can check that also. Also do not forget to unplug the kill switch in case it is something that easy.

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  • urgreathero

Posted June 03, 2008 - 04:42 PM

#10

nah its not the sp
it has tons of spark
its not getten gas
new plug is clean
so it has to be a carb.

  • Drew778

Posted June 03, 2008 - 07:29 PM

#11

nah its not the sp
it has tons of spark
its not getten gas
new plug is clean
so it has to be a carb.


I read someone else had a kinked fuel line?

So, no fuel is getting to the carb?

  • urgreathero

Posted June 04, 2008 - 02:33 AM

#12

I read someone else had a kinked fuel line?

So, no fuel is getting to the carb?


oh yea i nvr thought about that good idea
ill check that out aswell
nice one

  • lluks252

Posted June 05, 2008 - 07:50 PM

#13

I have a 2003 YZ450F, my 2 buddies, they have a 05 & 07 YZ450F, we all have to open the throttle like 2 or 3 times, half way each time, then fell out the compression stroke in the motor, & kick it like a MF...also check everything everyone else said before me...good luck let us know whats going on

  • urgreathero

Posted June 06, 2008 - 02:41 AM

#14

I have a 2003 YZ450F, my 2 buddies, they have a 05 & 07 YZ450F, we all have to open the throttle like 2 or 3 times, half way each time, then fell out the compression stroke in the motor, & kick it like a MF...also check everything everyone else said before me...good luck let us know whats going on


alrigth
i currently have whole bike striped to frame
going over everything to make sure its nothing major

  • mjw1

Posted June 06, 2008 - 07:12 PM

#15

Your pilot jet is plugged it is one of the jets next to the main pull it out blow air through it and the bike should fire right up.

  • urgreathero

Posted June 06, 2008 - 07:32 PM

#16

yup it was jet i changed it and put it back in and now it leaks gass out of backflow tubes
i think i put bowl on wrong

  • rexbond007

Posted June 07, 2008 - 07:34 AM

#17

the float bowl is now stuck, tap on the bowl an it may free itself.

  • urgreathero

Posted June 07, 2008 - 09:35 AM

#18

the float bowl is now stuck, tap on the bowl an it may free itself.


it was the float hidth i had to bend it down a lil that float tab next to needle





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