Jetting, basic FCR carb and jet location pictures

[husker525]

I have been overwhelmed with questions asking for pictures of how to rejet, or the locations of jets. I will try to add more pictures as time allows, but this is a start.





This is a view of the bottom of the carb, looking up towards the top. This large hole is accessed via a 17mm Hex drain plug.

The small hex shaped jet is the main jet, the small single slotted jet under the main jet, is the pilot jet.

The small jet on the bottom of the picture, is the air fuel screw. On 05 and up models, this is covered with a small metal plug that needs to be drilled out. Most people replace this jet with something like a ZipTye fuel screw, which makes adjustment easy. No need to remove anything to adjust the a/f screw after you install an aftermarket.



This is the top of the carb. Under the cover held down by the 2 small Allen head screws is the needle. You will need another Allen wrench to remove the needle once this cover is removed. You can access this directly from the top of the quad, no need to remove or loosen the carb.

I hope this helps.

[sam68]

Nice post this should help limit some of the many where is the air fuel mixture screw threads and the like, or at least we can simply send them to this thread...good job Husker.

[Tech5]

Thank you sooo darn much!!!

[Carlo#22]

Good post Husker!

[E_delacruz37]

Man this is really going to help out when I do my re-jetting. I just have one question. When you drill out the metal plug to install the new aftermarket a/f screw how do you avoid any metal shavings from entering the fuel screw port? Or does it not really matter? I don't want anything being sucked up.

[blair-racing]

wat is that jet called that is above the main its sort of at the one oclock position in the pic

[husker525]

The metal plug is so thin, there should be virtually no shavings, you can almost pound a sheet metal screw through it, which is what I used to pull mine out after a tiny pilot hole was drilled.

The small jet in the 1 o'clock position is what I think is the leak jet. I have never messed with it, nor needed to.

[1fast06yfz]

Originally Posted by husker525

The small jet in the 1 o'clock position is what I think is the leak jet. I have never messed with it, nor needed to.

FYI the jet at 1 o'clock is the starter jet and the leak jet is in the picture

[husker525]

Originally Posted by E_delacruz37

Man this is really going to help out when I do my re-jetting. I just have one question. When you drill out the metal plug to install the new aftermarket a/f screw how do you avoid any metal shavings from entering the fuel screw port? Or does it not really matter? I don't want anything being sucked up.

Originally Posted by blair-racing

wat is that jet called that is above the main its sort of at the one oclock position in the pic

Originally Posted by 1fast06yfz

FYI the jet at 1 o'clock is the starter jet and the leak jet is in the bowl

Thanks! I obviously did not know that!

[1fast06yfz]

just thought i would help for those that didnt know

[blair-racing]

thanks i didnt know either does that affect the carb in any way

[AK49YFZ]

Effort well spent husker nice job. Hopefully people will spend some effort to search for stuff

[8ball]

Good info! I have question I'm new to this. I used to have a bad fuel leak around this area so took it apart and found out it was pretty dirty in there so figured the float was getting stuck. It stopped leaking, now the other day I went to start it just to run it for a couple of minutes and now noticed fuel residue around the area u pictured above. Its wet around the 17mm plug and like accumilates around the fuel air screw so not really sure if this is normal since I just turned it on for a couple of minutes. I did turn off the fuel at the peck new to carbs always had FI. Thanks for any help I can get.

[kahon]

Thanks for the info

[Leo 450yfz]

Originally Posted by ellerymae27

hello,im happy to be here in this thread.

Damn Husker. You are popular with the spam bots...

[ocyamaha]

Hey there. looking to correctly jet my 05 yfz.
HMF pipe
oil mod
cam mod
no air box lid
foam filter.

it currently has a 160 main 42 pilot and 1 3/4 turns out on the a/f screw.
When I hit the throttle it breaks up a bit and i want it to be right.. so if you have a similar set up please give me you thought,
I live in WI if that helps. 690 feet above sea level
Also was wondering if i need to re-jet for winter?

Thanks to all who give their opinion.

[Bennett]

Originally Posted by ocyamaha

Hey there. looking to correctly jet my 05 yfz.
HMF pipe
oil mod
cam mod
no air box lid
foam filter.

it currently has a 160 main 42 pilot and 1 3/4 turns out on the a/f screw.
When I hit the throttle it breaks up a bit and i want it to be right.. so if you have a similar set up please give me you thought,
I live in WI if that helps. 690 feet above sea level
Also was wondering if i need to re-jet for winter?

Thanks to all who give their opinion.

Yes you should re-jet for winter....the cool, dense air makes the bike run leaner so you should richen it up to compensate for more air with more fuel.
You are way lean for all those mods. I would say a 48 pilot, 178 main and you should be good on the fuel screw with the bigger pilot. If you have the NCVQ needle, it should be around the 4th clip from the top. Good luck!

[ocyamaha]

ok thank you. I just ordered some new jets. The jets you just reccomended for using..48p 178m I should go up with both of them for winter correct? like one size?
thanks again

[Bennett]

Originally Posted by ocyamaha

ok thank you. I just ordered some new jets. The jets you just reccomended for using..48p 178m I should go up with both of them for winter correct? like one size?
thanks again

Possibly......or it could be good like that and you might want to go go down a size when it starts to warm back up. You'll just have to try a few sizes to see what works best with your quad, at your altitude, and with the weather in your area.

[Bennett]

Oh yeah.....try one thing at a time too, so you know what helps and what does'nt.