changing the pilot jet on 07 yz450


18 replies to this topic
  • Hurricane

Posted May 31, 2011 - 10:31 AM

#1

Well in trying to cure my decel backfiring issue I bought a 48 pilot thinking I would go up one from the stock 45. Man what a pain in the butt to change the jet? Do they make a special small screwdriver or something? I loosened the carb boot but the carb will barely turn to access the bottom of the bowl because it looks like the top of the carb is hitting the motor mount above it? Is there a trick to twisting the carb? I basically had to do it by feel because the carb doesn't turn enough to look up it and I had to use a screwdriver bit from a cordless drill to fit up there and then turn it with a wrench.

Oh Grayracer you were right about the 45 pilot. After getting the pilot jet out I found out it has a 42 PJ in it instead of the stock 45 so this is more likely my problem. But since I bought a 48 I didn't get to put it in to see if that will fix it since I need to run by the shop tonight and see if they will trade the 48 for a 45.:smirk:

  • RiderX

Posted May 31, 2011 - 10:34 AM

#2

I always just take the subframe off. It's more to take apart, but less of a hassle to maneuver the carb and less likely to cause wrench sized holes in my garage wall.

  • Hurricane

Posted May 31, 2011 - 10:37 AM

#3

after you take off the subframe will the carb just swing back so you can access the bowl? Can you just remove the top subframe bolts and swing the frame back and down after loosening the lower SF bolts?

  • motorider300

Posted May 31, 2011 - 11:35 AM

#4

You don't have to remove the subframe. Take off the seat & tank, then remove the head stay. The carb can be rotated enough to remove the pilot with a small screwdriver. It's a pain but its possible.

  • dirtdevil72

Posted May 31, 2011 - 11:38 AM

#5

Just rotate the carb a little and makes changing the pilot a breeze. 15 min Job.

  • Hurricane

Posted May 31, 2011 - 12:05 PM

#6

You don't have to remove the subframe. Take off the seat & tank, then remove the head stay. The carb can be rotated enough to remove the pilot with a small screwdriver. It's a pain but its possible.


I don't know what's more of pain removing the tank and head stay our just removing the seat and dropping back the subframe. Man I hope this gets it, this is a real pain to change a jet. I don't recall my 98' wr400 being this bad, I guess the aluminum frame is what is cramping everything???:smirk:

  • Hurricane

Posted May 31, 2011 - 12:06 PM

#7

Just rotate the carb a little and makes changing the pilot a breeze. 15 min Job.


Did you read my post above, the carb will not rotate because the top hits the head stay. Any other suggestions?

  • WGP

Posted May 31, 2011 - 12:49 PM

#8

I usually just pull the whole thing out (yes, subframe off) so I can clean it out at the same time.
Usually needs it, all jets come out ect...

  • RiderX

Posted May 31, 2011 - 12:53 PM

#9

I just remove the subframe and set it aside. You can rotate the carb enough to remove the bowl.

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  • grayracer513

Posted May 31, 2011 - 01:17 PM

#10

Well let's see...

I don't rotate the carb or remove the carb or the sub frame to change the pilot jet.

In the Common Threads Sticky that no one ever reads, there is something about changing late model pilot jets without moving the carb.

http://www.thumperta...ad.php?t=556427

  • dgcars

Posted May 31, 2011 - 02:26 PM

#11

Here's another, works for me....http://www.thumperta...131#post9945131

  • Hurricane

Posted June 01, 2011 - 10:15 AM

#12

Thanks dgcars and gray, I just wish I would have seen this before I left work yesterday. I ended up removing the tank and 1 of the head stays so I could rotate the carb enough to get to it, what a pain in the butt. Now if I could just see the pictures that are posted on this site I would be in great shape, photos are almost always blocked.

  • Polar_Bus

Posted June 01, 2011 - 12:03 PM

#13

I tried feeding the pilot up through the bowl bung plug. I just don't have the finger dexterity or patients to deal with that pilot jet surgery method. I just crack a beer, and yank the subframe and carb and do it old skool' . Am I spending more time changing the jet with my method ? Yup. Am I having less stress and verbal "Fbombs" with my method ? Yup. :smirk:
While im there I also yank the shock and antiseeze the bearings. No big deal to me.

  • dirtdevil72

Posted June 01, 2011 - 12:13 PM

#14

Did you read my post above, the carb will not rotate because the top hits the head stay. Any other suggestions?


I have the same bike and I can rotate a little to get a little screwdriver in there 15 min...

  • Hurricane

Posted June 02, 2011 - 01:55 PM

#15

I have the same bike and I can rotate a little to get a little screwdriver in there 15 min...


that's impressive, do you have small hands? a special shorty screwdriver? what's the trick.

  • dirtdevil72

Posted June 02, 2011 - 04:15 PM

#16

Real short screwdriver, and like grey said a paper clip or safety wire

  • fastyz250

Posted June 02, 2011 - 05:23 PM

#17

i can change them with hardly turning the carb i took a pocket screwdriver and cut the whole thing down to around two or three inches works great takes some patience though

  • Hurricane

Posted June 03, 2011 - 10:18 AM

#18

Real short screwdriver, and like grey said a paper clip or safety wire


I wish I could see the pictures of this paper clip trick, my computer here at works blocks them.

  • JDLowrance

Posted June 03, 2011 - 07:25 PM

#19

A small piece of properly sized diameter rubber tubing does the trick for me. Works for both the main and pilot. Unfotunately doesn't work for my WR due to starter and excess wires and cables that are in the way. Works great on the YZ though.

John





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