Backfire and Hesatation



2 replies to this topic
  • Ut426

Posted April 06, 2001 - 08:33 PM

#1

I have 01 YZ426F with aftermarket exhaust installed and jetted by the dealer. once i got it home i took test ride and got a little hesatation between 2nd and 3rd, also alot of loud backfires on deceleration. I am wondering if the bike is jetted wrong, or if cold rainy weather could cause this..... The only jetting change the dealer made was changing the main jet to a 160 from a 162 and said i was good???? PLEASE HELP

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

Posted April 07, 2001 - 06:35 AM

#2

Brandon,

I had this same problem when I put my E-Series exhaust on.

You need to turn your fuel screw out 1/4 turn at a time until the backfire stops or at least becomes less noticable. My 400 still backfires slightly but it runs so good with no hesitation I don't want to mess with it. If you get much past 2 1/2 turns (from fully closed) then you will need to go to the next size pilot jet. My 400 came stock with a 45 I now run a 48 with about 1 1/2 turns out on the fuel screw. You will need to check and see what the stock jetting is on the 426 since it is different from the 400. It runs real crisp and clean. I haven't run it with this rain we are having but I suspect I would have to turn it out 1/4 - 1/2 turn if I did. With weather like we are having here it makes for a lean condition since the air is more dense.

------------------
SHN
99'YZ-400 (Mine)
00' TT-R 125 (Hers)
91' KX-125 (Son #1)
93' CR-80 (Just sold it. Looking for another TTR125 for Son #2)
99' PW-80 (Son #3)

  • FlyGi

Posted April 08, 2001 - 07:02 AM

#3

If it's backfiring that means it is running lean. I have an '01 YZ426 with an E-Series. I ride and race between 2000 - 4500 FT. This works for me:

162 Main
45 pilot
2 turns out on fuel screw
needle on 3rd clip (from the top)


[This message has been edited by FlyGi (edited 04-08-2001).]





Related Content

Reviews

Yamaha YZ450F 2017 by Chris.GVS


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

Snake pit oct 30th by The Anvil


Dirt Bike   Dirt Bike Regional Discussion   California
  • Hot  293 replies
Forums
Photo

Michigan Motocross Tires by 288yz450


Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply
Forums
Photo

The "going back to the other darkside" adventure... by Monk


Dirt Bike   Make / Model Specific   KTM   250/350/450/505 SX-F & XC-F (4-Strokes)
  • Hot  94 replies
Forums
Photo

2016 YZ450 by CaptainKnobby


Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies
 
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.