brand new 09 yz450f wont run!!


18 replies to this topic
  • Dick Falcon

Posted January 10, 2010 - 11:27 AM

#1

okay guys bear with me i'm not a good writer.lol So i picked up my 09 yesterday it woudnt start.it took forever for the dealer to get it going, they suck!i rejetted it 48p 165m 1 1/2 turns on the fuel screw.it will start with the choke out and the hot start pulled in.once it starts it idles fine.it just super hard to start,im sure its the tight engine ant jetting.please help.I have an FMF mega bomb and a Q4 silencer.ill be riding in temps from 20-45 degs for the next month or so.

Thanks,jon

  • grayracer513

Posted January 10, 2010 - 11:46 AM

#2

Search, Find; Read:

http://www.thumperta...780#post8998780

  • racerxx276

Posted January 10, 2010 - 12:19 PM

#3

also check to see it the hot start is stuck open.. I have seen new YZ's delivered dry and they will stick, which make it very hard to start!

  • Wes Woodin

Posted January 10, 2010 - 05:18 PM

#4

its cold and new! That's normal

  • dvn

Posted January 10, 2010 - 06:03 PM

#5

its cold and new! That's normal


I agree. Went through the same thing with mine. After a few heat cycles, it starts 1st or 2nd kick, hot or cold.:moon: I am running the same jetting except I am 2 out on the fuel screw.

  • jlkfg

Posted January 10, 2010 - 06:10 PM

#6

I would make sure you prime it, twist the throttle about 4 times usually does it for me.

  • nwbikerider

Posted January 10, 2010 - 06:11 PM

#7

Choke richens it, hot start leans it. Why would you use both at the same time?

And I second the priming part. My KTM, I would never touch the throttle. My '09 YZ I did the same and it always took a number of kicks to start. Once I started twisting a couple times first, it fires on one or two kicks cold.

  • Dick Falcon

Posted January 10, 2010 - 07:28 PM

#8

thanks guys.i got three heat cycles on it now.Its lighting up way better.

  • Dick Falcon

Posted January 10, 2010 - 07:31 PM

#9

[quote name='nwbikerider']Choke richens it, hot start leans it. Why would you use both at the same time?

i had it choked after about 30 kicks i pulled in the hot start and it fired up.lol

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • stroker101

Posted January 11, 2010 - 04:50 AM

#10

hard to start here also.
did urs ever feel like it "didn't" have compression? i bought a new 2009 YZ450F(off the showroom flr / zero hrs) last wednesday and at times while trying to start it, it felt like a valve was still opened...

  • Dick Falcon

Posted January 11, 2010 - 06:34 AM

#11

not at all man the compression is alway the same so far.

  • ectm3

Posted January 14, 2010 - 12:09 AM

#12

I had the same problem,id check your sparkplug,if its not golden brown your too rich on the pilot jet.I run a ti ti dr.d pipe and header,pro flo twin air filter and stick with 45p-165m and switched the needle to nfpr which is half a clip richer than stock-1 1/2 on the fuel screw.I added the r&d power bowl as well.She fires on 2 kicks every time.All weather conditions -10 deg to+20 deg.

Edited by ectm3, January 14, 2010 - 12:15 AM.
add more info


  • grayracer513

Posted January 14, 2010 - 09:13 AM

#13

I had the same problem,id check your sparkplug,if its not golden brown your too rich on the pilot jet.

How would he be able to read the plug color? The bike is brand new.

  • usp4u

Posted January 14, 2010 - 01:50 PM

#14

I always refrained from touching the throttle on all my past fourstrokes, but this bike(08 450) really responds to two blips of throttle before kicking cold.
2 blips, choke set, kick from TDC, done.

  • dvn

Posted January 14, 2010 - 02:56 PM

#15

I always refrained from touching the throttle on all my past fourstrokes, but this bike(08 450) really responds to two blips of throttle before kicking cold.
2 blips, choke set, kick from TDC, done.


This is the routine that my 09 seems to like as well.:banghead:

  • stroker101

Posted January 14, 2010 - 11:41 PM

#16

i installed a RideEngineering fuel screw it the carb the other day, 2-1/4 turns out. turn on the fuel, pull the choke out, 2 blips of the throttle, and kick twice and it starts.
i had put some run time on the bike while on the stand. it seems to have done it some good.

the issue with "low compression/valve opened", i beleive it to have been, going through it's cycles trying to find TDC

  • ectm3

Posted January 15, 2010 - 09:31 AM

#17

How would he be able to read the plug color? The bike is brand new.


Dont people make sure the bike runs befor they purchase it?I wouldnt buy a bike unless i take it for a boot around the parking lot,and let it idle.If it doesnt run-dont buy it! I assume too much.The plug color is just a guid line.

  • grayracer513

Posted January 15, 2010 - 09:49 AM

#18

Dont people make sure the bike runs befor they purchase it?

Apparently not everyone. But then, a lot of people don't read the whole thread before posting, either :banghead: See the first post, it explains things.

  • Dick Falcon

Posted January 15, 2010 - 06:27 PM

#19

its good now guys!i did a few heat cycles now it fires right up.and yes it was running fine at the dealer.i think im going to love this bike,after five years on ktms im stoked to get going on this yzf.





Related Content

Wiki
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info


Articles
  • 0 replies
Forums
Photo

yz250x vs 450 4t comparisons (preferably desert riding) needed by JakeNorthrupYZ450F


Dirt Bike   Make / Model Specific   Yamaha   Yamaha 2-Stroke
  • 9 replies
Forums
Photo

First Hare scramble tips by dhend8


Dirt Bike   General Dirt Bike Forums   General Dirt Bike Discussion
  • Hot  33 replies
Reviews

Yamaha YZ450F 2017 by Chris.GVS


Yamaha YZ450F 2017
  • - - - - -
  • 0 reviews
Forums
Photo

Megabomb Fitment by 288yz450


Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply
 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.