Quantcast
Jump to content

  • Join Today, It's Simple and FREE!

    As a member, you can post in our forums, upload your photos and videos, use and contribute to our downloads, create your own member page, add your ATV events, and even start your own ATV club to host your own club forum and gallery.  Registration is fast and you can even login with social network accounts to sync your profiles and content.

crprestridge

2005 Yamaha yfz450 running lean, i think?

Recommended Posts

i own a 2005 yfz 450 and i think it's running lean. when i get 3/4 to wide open it misses or cuts out. i have a k and n filter, yosh exhaust sytem and is jetted with a moose racing jet kit. main jet is dj132, pilot jet is dpjm048 and needle is set on #4. the fuel aire mixture screw was 1 and a 1/2 turns out but now 2 turns. spark plug is white. what should i do now?

Share this post


Link to post
Share on other sites




Put a bigger main jet it. What size jets did the kit come with(I'm not familiar with moose brand jets)? The 48p sounds like a normal size, but I'm not sure about main. I used a gytr jet kit that came with my pipe and use main jets between 165-170 and pilots 45 or 48. If you'r screw is out 3 or more turns, you need a bigger jet.

Share this post


Link to post
Share on other sites
i own a 2005 yfz 450 and i think it's running lean. when i get 3/4 to wide open it misses or cuts out. i have a k and n filter, yosh exhaust sytem and is jetted with a moose racing jet kit. main jet is dj132, pilot jet is dpjm048 and needle is set on #4. the fuel aire mixture screw was 1 and a 1/2 turns out but now 2 turns. spark plug is white. what should i do now?

Did any of the Suggestions fix your problem.....Everyone was right on top of it.....

Your Main jet Controls 3/4 to WOT......

Also,,,,,,,Make sure that the Float is set right..... To high will make it run Rich....Too low will make it run lean....When you do plug Chops......Make sure you use a new Spark Plug, Clean Air Filter and New Gas....If you can figure out a way to mark the 4 Different Positions of your Throttle location when you are Tuning it will be easier to identify the problem area for jetting....

The air screw is most effective between idle through 1/8 throttle.

The pilot (slow) jet 1/8 through 1/4 throttle.

The slide 1/8 through 1/2 throttle

The jet needle 1/4 through 3/4 throttle.

The main jet 3/4 through wide-open throttle

Share this post


Link to post
Share on other sites

Check how you have you slide installed compare it to a service manual diagram. The design Yamaha used makes it easy to put the slide plates in backwards or upside down either way you'll get erratic running issues.

Share this post


Link to post
Share on other sites


Guest michealwaiting

Was curious if it got better?

Share this post


Link to post
Share on other sites

i had a friend of mine re-jet the carb. but yes, it is running alot better. done a few more things to it since but still haven't gone into the motor except to degree the exhaust cam back a bit.

Share this post


Link to post
Share on other sites
i had a friend of mine re-jet the carb. but yes, it is running alot better. done a few more things to it since but still haven't gone into the motor except to degree the exhaust cam back a bit.

Glad to hear you solved your by re-jetting the carb. Did you install a larger main jet?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Similar Content

    • By LMI
      Was using the quad the other day to shuttle wood from my pickup to my wood pile.  When the job was done I turned off the Quad and heard a bit of a racket from the front end.  When I got down underneath the sound seemed to be coming from the fan housing.  fan was moving in spurts and not quickly... much like a computer case fan that's had it's day.  What I know.
      Temp sensor is ok, as the fan tries to activate fan is getting some voltage as it is attempting to spin.  When I first bought it used I tested the fan direct to battery and it was fine. The fan was working ok even not direct wired as I went on a couple of rides and when stopped and idling the fan did run Seems to be free spinning with my finger read up in the manual and they require me to drop the rad.  now I'm not opposed to that as the rad has some damaged areas I want to try and straighten out.  But if I can get the fan working without, I can leave the rad as it is until next year.
      Fan assembly is about 300 bills, any work arounds or alternatives?  I even thought large computer case brushless fan.  smaller ones are about $7 larger ones better quality probably far below the 300.  They run standard 12v DC.
      Anything I should be doing before dropping the rad... other than check for obstructions even though it seems to spin, and trying to hardwire it to the battery again for a test to see if it acts the same?
    • Guest Fox300exchic
      By Guest Fox300exchic
      The Hop-Up: You may be saying to yourself, “that’s a chick bike,” and you’re right. But honestly, it’s so much more than that. It’s one badass bike. http://www.quadmagazine.com/quad/features/article/0,24942,1587044,00.html
    • Guest Fox300exchic
      By Guest Fox300exchic
      If we had a dollar for every time the question “Which is really faster, the 700 or the 450?” shows up in our inbox, mailbox, or voicemail, we’d be putting this magazine together from a bungalow on a barely inhabited tropical isle named Quadhama.
      http://www.quadmagazine.com/quad/features/article/0,24942,1603755,00.html
  • Recently Browsing   0 members

    No registered users viewing this page.


×