No difference in adjusting the fuel screw.

6 replies to this topic
  • underground-mpyre

Posted October 05, 2016 - 04:06 AM


I installed a FCR Wr450 carb on my Wr426. Now I can't tell any difference with trying to adjust the fuel screw in any directions, knowing there would be subtle changes. I have adjust the fuel screw down all the way and opened it up to 2 1/2 turns out and no difference. Just the stagger from running low idle.


I have listened to the throttle blip is crisp and on point at 1 3/4 turns. 2 turns out the throttle hangs a bit while riding. Again, trying to adjust this fuel screw makes no difference idling. No stagger turning it in or running faster turning it out.


I have watched a few videos and I don't even come close to the adjustments in these videos. Thoughts?










  • underground-mpyre

Posted October 05, 2016 - 04:09 AM


The oem and jd jetting fuel screw is the same.1475669348062.jpg

  • Krannie McKranface

Posted October 05, 2016 - 05:13 AM


This is not uncommon.

The 1.75 turns location you found for best throtte response, and the stumble at closed, are all the desired traits you are looking for.


To many parts to wear inside the carb to have it act like a brand new carb


Was the motor HOT when you adjusted the f screw?

I'll bet it runs MUCH better in general however!

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  • underground-mpyre

Posted October 05, 2016 - 05:41 AM


Yes, it was hot after 10-15 minute ride.


Brand new everything on the internals.


Just aggravating trying to get this right.

  • William1

Posted October 07, 2016 - 04:48 AM


Some bikes, when set to the right idle speed (appx 1,850 rpm) the bike is just coming on the needle and therefore diminishes the apparent effect of the fuel screw. Lower the idle speed temporarily and set the fuel screw, then when set, raise the idle speed back up.

  • Krannie McKranface

Posted October 07, 2016 - 05:15 AM


^^^ Yes


I forgot to point out that when you adjust the fuel screw you must start with the lowest possible idle on a hot motor and the fuel screw below 1.25 turns out.

  • underground-mpyre

Posted October 07, 2016 - 05:55 AM


Yes, I started with the lowest idle on a hot motor and really can't tell the difference at all starting at 1.25 turns out.


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