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2016 yz450f.jpg

Yamaha YZ450F (2016)


Owner: Goof331
Added on December 04, 2016


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2001 YZ426F PROBLEMS!


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23 replies to this topic
  • dirtpaw12

    TT Member

64 posts

Posted August 10, 2016 - 03:48 PM


Okay so I bought this bike sometime in the beginning of the year. It didn't want to start when I first got it so I took the carb off and cleaned it, went through the jets with a bobby pin and what not, made it start but had to be on choke if I wanted to run it without it cutting off when I let off the gas, so I took it apart again and cleaned it but it did not help at all so I decided just to run it on choke. It will not cruise at a steady speed because it's "jumpy" with the throttle in one position like its bogging so I just blip it unless I'm constantly increasing speed. Fast forward six months I'm still riding it with the choke on, backpopping every time I let off the throttle. I've also tried messing with the mixture knob but does nothing but help. I have posted this before but none of the answers I got worked and I'm completely fed up with it. Any help??

 

I only paid $1200 for it. 



  • damnbiker94

    TT Member

58 posts
Location: Georgia

Posted August 10, 2016 - 04:12 PM


Check valve clearance, check for vacuum and exhaust leaks, and/or clean the carb and jets thoroughly. Lots of posts on here on how to do all of these correctly.

  • grayracer513
42,929 posts
Location: California
Garage View Garage

Posted August 10, 2016 - 07:31 PM


If it needs the choke on to stay running, the pilot jet is still clogged. 



  • 03wr450fun

    TT Newbie

14 posts

Posted August 20, 2016 - 05:05 AM


How did you get on dirtpaw. Sounds the same as the issue i am having with my 2000 yz426f

  • Krannie McKranface
36,207 posts
Location: California
Garage View Garage

Posted August 20, 2016 - 06:10 AM


There is a passage above the pilot with a 90 bend in it

Use fishing line and 'real' carb cleaner (carefully; don't get any on the slide plate) to clear the passage

 

Buy a brand new pilot jet.

 

Using a bobbypin to clean jets is like using a wooden down to clean a gun barrel. It does not work.



  • Chris7280

    TT Newbie

7 posts
Location: North Dakota

Posted August 20, 2016 - 06:43 AM


Is it hard to start? You are defiantly running too lean it sounds like. Id make sure your valve clearances are good before do anything else with the carb if they are off more than .15mm u could have a bad valve and make sure the timing is spot on cause it won't make any difference at all messing with the carb if those are out of spec. Next make sure you are running premium gasoline. If those are all good make sure u have the stock jets in the carb and the slide and needle jet are straight and move smoothly. If that doesn't help than it means the carb is still dirty or u have an airleak between the carb and and intake.

  • grayracer513
42,929 posts
Location: California
Garage View Garage

Posted August 21, 2016 - 07:00 AM


Buy a brand new pilot jet.

 

Using a bobbypin to clean jets is like using a wooden down to clean a gun barrel. It does not work.

 

Completely unnecessary.   "Bobby pins" are completely useless, though.  Read:

 

http://www.thumperta...o/#entry6879695



  • dirtpaw12

    TT Member

64 posts

Posted August 21, 2016 - 12:13 PM


Bike starts as easy as any other, it might cut off if it hasn't been ridden in a while but starts right back up and bike
has never seen anything other than 93 octane gas

Edited by dirtpaw12, August 21, 2016 - 12:19 PM.


  • 03wr450fun

    TT Newbie

14 posts

Posted August 21, 2016 - 03:02 PM


With my issue my idle screw only changes the idle speed when the choke is on. When the choke isn't on i can wind it all the way in or out and it makes no difference

  • dirtpaw12

    TT Member

64 posts

Posted August 21, 2016 - 03:38 PM


With my issue my idle screw only changes the idle speed when the choke is on. When the choke isn't on i can wind it all the way in or out and it makes no difference


Same boat

  • 03wr450fun

    TT Newbie

14 posts

Posted August 21, 2016 - 04:41 PM


I haven't checked valve clearances yet. Waiting for my feeler gauges to turn up

  • 03wr450fun

    TT Newbie

14 posts

Posted November 01, 2016 - 05:18 PM


New pilot jet in still will only just idle with with idle screw right in and backfires like a bitch. With choke on and idle screw wound out it idles perfectly and doesn't backfire when i blip the throttle.

  • dirtpaw12

    TT Member

64 posts

Posted November 01, 2016 - 05:22 PM


Make sure the mixture screw has not rattled out, that was my problem

  • 03wr450fun

    TT Newbie

14 posts

Posted November 01, 2016 - 07:50 PM


Its still there mate i was winding it in and out. I thought the mixture may have been wrong

  • dirtpaw12

    TT Member

64 posts

Posted November 01, 2016 - 08:07 PM


Make sure the fuel slide is not upside down, the letter on the slide should be an M, not a W

  • 03wr450fun

    TT Newbie

14 posts

Posted November 01, 2016 - 09:19 PM


Cheers mate i will pull it off AGAIN and have a look

  • 03wr450fun

    TT Newbie

14 posts

Posted November 02, 2016 - 12:37 AM


Ok slide was upside-down cheers dirt paw. Put back together. And now can not start the bastard. Just keeps kicking all the way through the stroke. It was not like this earlier today. The bike would start quite easily with the stsrting process .

  • dirtpaw12

    TT Member

64 posts

Posted November 02, 2016 - 02:02 AM


My bike won't start with the idle screw turned to high or low try adjusting that

  • dirtpaw12

    TT Member

64 posts

Posted November 02, 2016 - 02:10 AM


Not screw but the black knob

  • BushMaster1911

    TT Newbie

2 posts

Posted November 03, 2016 - 09:18 AM


Can anyone tell me if the stator cover from 450 will fit the 426 in of the same year? (2001)





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