YZ Needle

1 reply to this topic
  • 123BigcoopDawg576

Posted September 16, 2008 - 06:00 AM


I have noticed that when it comes to buying the yz needle for the carb that there is about 10 different opions.

Can anyone tell me what this is all about and how do i go about figuring how each one is different in how they preform.


13 SKU: 5TA-14916-LR-00
NEEDLE (#NFLR) STD STD 1 $9.76 Add to Cart
13 SKU: 5TA-14916-LN-00
NEEDLE (#NFLN) AP AP 1 $9.76 Add to Cart
13 SKU: 5TA-14916-LP-00
NEEDLE (#NFLP) AP AP 1 $9.76 Add to Cart
13 SKU: 5TA-14916-L1-00
NEEDLE (#NFLQ) AP AP 1 $9.76 Add to Cart
13 SKU: 5TA-14916-LS-00
NEEDLE (#NFLS) AP AP 1 $9.76 Add to Cart
13 SKU: 5TA-14916-LT-00
NEEDLE (#NFLT) AP AP 1 $9.76 Add to Cart
13 SKU: 5TA-14916-LU-00
NEEDLE (#NFLU) AP AP 1 $9.76 Add to Cart
13 SKU: 5TA-14916-PN-00
NEEDLE (#NFPN) AP AP 1 $10.38 Add to Cart
13 SKU: 5TA-14916-PP-00
NEEDLE (#NFPP) AP AP 1 $9.76 Add to Cart
13 SKU: 5TA-14916-P1-00
NEEDLE (#NFPQ) AP AP 1 $9.76 Add to Cart
13 SKU: 5TA-14916-PR-00
NEEDLE (#NFPR) AP AP 1 $9.76 Add to Cart
13 SKU: 5TA-14916-PS-00
NEEDLE (#NFPS) AP AP 1 $9.76 Add to Cart
13 SKU: 5TA-14916-PT-00
NEEDLE (#NFPT) AP AP 1 $9.76 Add to Cart
13 SKU: 5TA-14916-PU-00

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • grayracer513

Posted September 16, 2008 - 06:36 AM


Go to this site and download a manual for an '06 or '07 YZ450:


On page 7-7, it goes into an explanation of how the needles differ. All NF** needles have the same taper. The 4th character of the code letters tells the diameter of the straight portion of the needle. The third character tells how far up or down the needle the taper starts.

The diameter of the upper straight portion of the needle begins to affect the mixture as the throttle is raised off idle, and is most significant between 1/8 and 1/4 throttle, after which its effect tapers off quickly, and the taper becomes more meaningful. This simply because at about 1/4 throttle, the straight portion is fully drawn up and out of the needle jet. The taper of the needle is the primary influence on mixture control between 1/4 to the area of 3/4-7/8 throttle, after which, it's all main jet. Changing the main jet influences part throttle performance somewhat, more so at higher throttle openings, because the fuel metered by the needle comes from the main.

The Standard YZ450 needle is the NFPR for an '06, and an NFLR for the '07. These two needles are identical except that the clip grooves in the NFLR are moved up half a step on the needle compared to the NFPR. This means that the NFLR with the clip in 4 is half a step leaner than an NFPR with the clip in 4. Not a great deal of difference.

When selecting a needle, be sure you get one for the correct year, as older carbs used a different taper, and it's probably safe to start with the standard needle. Also, it would be wise to poll those who have swapped a YZ needle into a WR and see what they ended up with.

Related Content


BIGBORE FOR YZ450F 2006? by Taattie94

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 3 replies

2016 YZ450 by CaptainKnobby

Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies

Wilson the Blue Privateer by jetfuel

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  50 replies

Yamaha YZ450F 2017 by Chris.GVS

Yamaha YZ450F 2017
  • * * * * *
  • 1 review
  • Last review by Tommyk_55
  • On January 15, 2017
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info

  • 0 replies

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.