Jump to content

04 450 Carb Dial

By mxrayser,
in YZ400F/426F/450F/450FX

 Share

Recommended Posts

Veteran

flintlock28

Posted
Posted

It is an aftermarket fuel screw.........

The stock carb comes with a recessed fuel screw, that is a pain in the azz to adjust, since it sits so far recessed. Some aftermarket companies (i.e. Zip-Ty) and other's offer an aftermarket screw that replaces the stock recessed. You remove the stock screw, and put in the new knurled knob. I'm guessing the color is an anodized red color right?? If so, than the previous owner must have installed a Zip-Ty

I have one on my bike, and it is a great product for adjusting the fuel mixture from idle to about mid-throttle. To adjust it to give you the best throttle response:

Make sure the bike is fully warmed up...Ride it at least a few minutes.

Let the bike idle in neutral, and then turn in the idle knob to increase the idle above normal. Turn the Fuel screw slowly in until you hear the idle begin to drop, and the bike will nearly stall. Begin to slowly turn the knob out until the bike reaches maximum R.P.M. Stop when it reaches maximum (highest) R.P.M. At this point you will be at approximately the best setting for the fuel screw. The 1,2,3,4, numbers are marked on the fuel screw, so that you can tell how many 1/4 turns you have moved the screw in or out. If my bike's fuel screw is not set correctly, than the bike will feel sluggish (i.e. running rich), a little adjustment of the fuel screw, and it's pulling the front wheel skyward again...Hope this helps...you can also do a search of Zip-Ty fuel screw.

Don

Oh, one last thing; When you turn the fuel screw in....DON'T bottom the fuel screw all the way in TOO hard. If you turn it in all the way TOO hard, you could crush the tiny little tip on the end. In most cases, I think you need the fuel screw to be turned out from fully in, between 3/4 of a turn to 2 full turns out for normal operation. If you have to be turned out less than 3/4 of a turn, or more than two full turns out, than I think the leak jet has to be changed.

Link to comment
Share on other sites
Collaborator

mxrayser

Posted
  • Author
Posted
It is an aftermarket fuel screw.........

The stock carb comes with a recessed fuel screw, that is a pain in the azz to adjust, since it sits so far recessed. Some aftermarket companies (i.e. Zip-Ty) and other's offer an aftermarket screw that replaces the stock recessed. You remove the stock screw, and put in the new knurled knob. I'm guessing the color is an anodized red color right?? If so, than the previous owner must have installed a Zip-Ty

I have one on my bike, and it is a great product for adjusting the fuel mixture from idle to about mid-throttle. To adjust it to give you the best throttle response:

Make sure the bike is fully warmed up...Ride it at least a few minutes.

Let the bike idle in neutral, and then turn in the idle knob to increase the idle above normal. Turn the Fuel screw slowly in until you hear the idle begin to drop, and the bike will nearly stall. Begin to slowly turn the knob out until the bike reaches maximum R.P.M. Stop when it reaches maximum (highest) R.P.M. At this point you will be at approximately the best setting for the fuel screw. The 1,2,3,4, numbers are marked on the fuel screw, so that you can tell how many 1/4 turns you have moved the screw in or out. If my bike's fuel screw is not set correctly, than the bike will feel sluggish (i.e. running rich), a little adjustment of the fuel screw, and it's pulling the front wheel skyward again...Hope this helps...you can also do a search of Zip-Ty fuel screw.

Don

Oh, one last thing; When you turn the fuel screw in....DON'T bottom the fuel screw all the way in TOO hard. If you turn it in all the way TOO hard, you could crush the tiny little tip on the end. In most cases, I think you need the fuel screw to be turned out from fully in, between 3/4 of a turn to 2 full turns out for normal operation. If you have to be turned out less than 3/4 of a turn, or more than two full turns out, than I think the leak jet has to be changed.

Don, Thanks for the detailed info, appreciate it George AKA mxrayser

Link to comment
Share on other sites
Experienced

ben_suhard

Posted
Posted
If you have to be turned out less than 3/4 of a turn, or more than two full turns out, than I think the leak jet has to be changed

Usually that indicates the need for a pilot jet change.

Yep, pilot jet. The leak jet is for the carby pump.
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

ThumperTalk

Register a new account Sign In Now
 Share
Go to topic listing
×
×
  • Create New...
Terms of Use
Copyright
Privacy Policy