rejetting after removing snorkel

Assuming the exhaust is left stock and the bike is ridden at sea level, what jetting is required if any when the snorkel is removed? Should I switch needles too or do anything to the stock needle?

Do you have an S, E, or K?

The common mod with the S, as I'm sure you've seen by searching past threads, is to go from a 142.5 main to a 150; change the pilot from a 22.5 to a 27.5; remove the snorkel and cut the opening to a 3"x3" hole; and that's it. I've done the above mod and been happy. No need to change or move the needle.

Check this jetting database post, and you can see what everyone else is using.

I have an 01' E

I asked my dealer exactly the same thing (and i'm assuming that you removed the restrictor in the muffler) and he told me:

Stock Main : #165

Stock Pilot: #45

After removing restrictors, change main jet to

#168 and raise the needle one clip.

This was the advice i was given but there are so many different combinations depending on temperature/altitude etc.

I also ride mainly near sea level and have the same bike.


[ December 29, 2001: Message edited by: DRZ_DownUnder ]

Tony: With stock exhaust raise the needle one and go to a 155 main jet. If you like that and want a little more at the expense of fuel milage try a 160 main. I believe the 155 will make a huge dif considering your mild temp and high humidity.If you have cold morning startup and warmup problems then go with a 48 slow jet.

Leave the exhaust stock unless you are going to race it. Cut out the end cap with a 1 3/8 hole saw before spending any money but that is overated if you do the jetting and needle first.

Changing to a (01) Yamaha YZ426 needle will wake up the mid range. Yamaha PN 5JG-14916-JP-00. It is the OBEJ'P needle. You may be able to borrow one from a 426 rider who has switched to the EKP needle which is the next step up from the stock one.

These changes pretty are conservatave but I believe in adding incrementally. You can go way farther and gain little or nothing.

The jets are under $5 and the needles $8 to $15 depending on your dealer.

There is no bigger bang for the buck!

Tony: one more thing. Before changing to a 48 slow jet open up the slow fuel screw a turn. It does basically the same thing as putting in a bigger slow jet. If you have the carb off the bike the slow fuel screw can be made more acccessible by filing away the shroud. It is inside a tunnel for some odd reason making adjusting pretty miserable. I use a allen wrench that has a flat ground on the short end as a screwdriver.

Still haven't spent much money yet have you.....

Where is the fuel screw? Is that the same thing as the idle screw? The one with the black knob? I think I"m all set as far as knowing how to rejet. One of the guys did a good post on it. However, I have no idea how to change or even adjust the needle? Any ideas?

Originally posted by TonyRomero:

Where is the fuel screw? Is that the same thing as the idle screw? The one with the black knob? I think I"m all set as far as knowing how to rejet. One of the guys did a good post on it. However, I have no idea how to change or even adjust the needle? Any ideas?

Fuel screw is located on the bottom of the float-bowl, forward of the drain plug and it's INVERTED and recessed up in a small hole/tube. Locate the drain plug on the bottom of the float-bowl and then slide your finger forward towards the engine. You will find a hole; it's up inside that hole.

Needle: Changing the needle can be done without removing the carb from the bike. Remove seat, tank and left-side panel(the one w/ the airfilter access cover). Then remove the cover on top of the carb(2 allenhead screws) w/ a metric allen wrench(can't remember size). Look straight down into the carb and you will see yet another allenhead screw(this one is bigger). Removing that screw will expose the upper portion of the needle. Using long-nose needle pliers, or something else long and skinny, grasp the top of the needle and pull it out. Set the clip on the needle one notch below where it is now effectively raising the needle. Stock clip position is 4 notches from the top. Did I miss anything guys? Good luck ! :)

Thanks! I have my needle on order now. Where should I set the clip? I have heard "third", but do they mean third from the top, or from the bottom?

Originally posted by TonyRomero:

Thanks! I have my needle on order now. Where should I set the clip? I have heard "third", but do they mean third from the top, or from the bottom?

I don't have any experience with the Yamaha needle, but the stock needle clip position is 4th from the top. I raised my stock needle 1 notch so now the clip sits in the 5th position from the top.

Tony : Set the new YZ needle 3 down from the top. Go ride it and get it good and hot. If it burps a little when chopping the throttle back then you can reset the clip at the second notch from the top. That is for the YZ needle now. The stock needle which is fatter and has a shorter taper runs better in the 5th or 6th position down.

Assuming you are still at sea level in Florida.

hey guys, what is the easiest way to turn the fuel screw with the carb on? If I go to the 155 main, the YZ needle on the 3rd clip , and completely stock exhaust, will I need to turn the screw at all.? The only thing I have done so far is pull the snorkel. I have the jets and needle on order. Is it better to close the fuel screw completely and then count the turns out, or simply add turns to the stock setting?

Close it first if you are not absolutely sure to the setting.

Never mind, I'm on the list for the "tool" !

I'd still like to know if you should close it completely then screw out, or simply screw out from the stock setting.

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