Fuel Screw Confusion


4 replies to this topic
  • CharlesFP

Posted March 31, 2006 - 10:11 PM

#1

I've done the research, and even in the most consise explanations about adjusting the fuel screw, the words "fast idle" are mentioned. What the heck is a fast idle? Without a tachometer or the ear of a veteran mechanic, how does one determine when to stop turning the idle screw once a fast idle has been reached?
Also, does anyone have any pointers about installing the Zip Ty fuel screw on the FCR carb for the WR 450? This is the carb that has a plug in the fuel screw opening. What is the proper way to remove that plug?

  • Matty05

Posted March 31, 2006 - 10:21 PM

#2

A fast idle is needed to get the proper fuelage at the low rpms.
Just turn the idle up a bit so it runs a little high from where you would normally set it.

Only you USA guys get the plug to block off the fuel screw. I have read that some people take to it with a small drill, screw in a screw and pull it out with pliers.

To swap to the zip-ty fuel screw, just screw out the old one, transfer the tiny o-ring and tiny washer to the zip-ty and screw it back in.

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  • OneToGo

Posted March 31, 2006 - 10:40 PM

#3

A fast idle is needed to get the proper fuelage at the low rpms.
Just turn the idle up a bit so it runs a little high from where you would normally set it.

Only you USA guys get the plug to block off the fuel screw. I have read that some people take to it with a small drill, screw in a screw and pull it out with pliers.

To swap to the zip-ty fuel screw, just screw out the old one, transfer the tiny o-ring and tiny washer to the zip-ty and screw it back in.


Or you can pick it out, but being where it is, I found it easier to remove the carb and punch it out. You may want to replace all those carb screws while you are at it. Metric thread M4 x12mm and 8mm for AP cover, Allen Heads are popular, most TTers have had problems with them stripping- depends which type are installed.

As Matty says, run high idle (the manual recommends this as well) around 1700-1900rpm. This can be judged as a fast tick-over where there is no hesitation or stumble. Believe me, solves a lot of starting and Off idle fuelling problems...

If you are worried about overheating then dont, just kill the motor if you idle more than 2 minutes with a warm engine (as per manual-Again)

enjoy :thumbsup:

  • old man dan

Posted April 01, 2006 - 08:19 AM

#4

I just stuck a scribe into the hole thats already in the plug and pulled it out. It came out really easily. Before you remove the original fuel screw, count the number of turns it takes until it bottoms gently then remove it, make sure you get the washer, spring and o ring, transfer to the new fuel screw and reset to the same adjustment as the old screw for starters. then you can adjust per the procedure.

  • dl19

Posted April 01, 2006 - 06:14 PM

#5

You don't need to remove the carb. Just pull it back and turn it out the left side as far as you can. Then you can turn the bottom out to work on the jets, and then turn the top out to work on the needle. Just take a short wire, bend a small hook, and pop out the cover. It is very easy to remove. Don't go drilling on it because you have to drill it fully out, and then you wil increase the chance of messing up your carb for no reason. You can replace all your needed carb screws at the same time. If you bike is dirty make sure you get both sides of the carb boots really clean.




 
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