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Discussion Starter #1
Hello all. First post here.
I've been having issues with my Raptor for the past 4 months. And have tried sorting things out on my own - to no avail. Thus, here I am..I need a second opinion! After reading through multiple threads to try to find an answer (again with no success), I know that I need to tell everything so you guys know whats going on. I'll start with alll the details, and I'll sum it up at the end if you don't feel like reading.

2004 Raptor 660 - Stock Carbs and Jetting. No additional mods at all - the bike is STOCK in all aspects.

Bought the bike used in Oct. of last year. Ran great, everything was fine. Then needle and seat started to stick and the carbs would leak at idle and when the bike was off.

I bought a new needle and seat (from Yamaha Dealer) in January, as well as float bowl gaskets, and put them back onto the bike. Ran fine. Then I noticed that there was a leak on the intake boot that sits between the carbs and the head. This caused the quad to run lean (red hot pipes). So then I bought new intake boots and put them on. While that was happening, I decided to clean the carbs because the bike would backfire through the exhaust when you were running around half throttle and then hit the gas to go faster.

Mistake.:mad:

Took everything apart. Kept each part seperate for carb 1 and 2. Soaked in petroleum based solvent...the usual. So I go to put things back together. I have the service manual so I follow everything to factory specs...making sure that the right size jets go in the appropriate carb, etc etc following the manual.OK great.

Ever since then the bike will not run right. I've taken things apart and adjusted almost 1000 times. Tried every possible combination for Needle Jet, idle screw, tried to sync the carb butterflies 2 different ways....nothing and I mean nothing works. Its always the same issue. Bike idles fine..beautifully. But from 1/4 to 3/4 throttle it is backfiring, spitting, and stumbling. I can give it full throttle from idle and it takes off! And if I'm riding it I can go full throttle all day and have no issues. Its the mid range which plauges me. But i've adjusted the needle jet to every position.

Also, I know that it is NOT THE PARKING BRAKE OR REVERSE LIMITER. because i've had the bike running WOT down the field with no issue at all.

So here's my theory. When I took the carbs apart the first time, something must have happened: I messed up the jets- whether I marred them or did whatever to them.

TOO LONG/DIDN'T READ


Stock Raptor, Stock Jets
Clean Carbs
NO LIMITER ISSUE
With stock specs (clip 3 needle) 1-3 turns idle screw
Bike wont run right - 1/4-3/4 hesitation, fine WOT


I'm thinking that I will next get a new jet kit (stock of course) and see where that gets me.

Just looking for a second opinion? Am i doing the right thing?

ANY...and i mean ANY ideas are appreciated!!! Thanks!
 

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Master of the Electron
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Your symptoms are similar to those I've heard of when an emulsion tube (needle jet) is plugged or a main nozzle has been installed backwards (this is not even shown in the factory manual)...

Of course, you could have the wrong jets in the wrong places, but unless you detail each carb and all its jets as you have installed them, we'll never know.
 

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Discussion Starter #3
The main nozzle may be an issue... when I was putting them back together I was unsure about which way faced up (referenced with carbs on the bike). But then I tried to put them in both ways, and with the tapered side up, the needle jet would not even thread in. Unless it has to be put in very carefully. So as it stands now, the Nozzle is in with the flat side up. I'll definitely try to reverse them tomorrow!!

As for jets being in the right spot, I'm certain that they are. I checked the numbers and markings as i put them back together.

I have a feeling this may help...because it was something I was concerned about from the beginning...

Thanks again!
 

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I am unique
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The main nozzle may be an issue... when I was putting them back together I was unsure about which way faced up (referenced with carbs on the bike). But then I tried to put them in both ways, and with the tapered side up, the needle jet would not even thread in. Unless it has to be put in very carefully. So as it stands now, the Nozzle is in with the flat side up. I'll definitely try to reverse them tomorrow!!

As for jets being in the right spot, I'm certain that they are. I checked the numbers and markings as i put them back together.

I have a feeling this may help...because it was something I was concerned about from the beginning...

Thanks again!
The emulsion tube must be positioned so that the larger opening is up facing the carb throat, this small tube has a larger opening and it faces upwards, if it is installed upside down, the engine will idle flawless but will not rev up at all, in the cases I have seen, this is what happens. Unless you have one upside down and the other is in proper, I cant see how you can get it to rev up..........
 

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Discussion Starter #5
OK so here is an update.
I tried to switch the emulsifier, but when I did I couldn't get the needle jet to screw back in correctly.

The first picture shows how the emulsifiers were installed in the carb before i tried to switch them....It seems that one end of the nozzle is slightly smaller in diameter than the other, and this is the side that will fit easily into the hole.

However when I try to install the emulsifier with the larger (tapered) end facing up toward the throat of the carb, the needle jet doesn't screw in at all, as shown in the other picture.

Maybe i'm missing something here (probably lol) or maybe these arent the stock needle jets?? I verified the sizing and placement again on the carbs.
 

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I am unique
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OK so here is an update.
I tried to switch the emulsifier, but when I did I couldn't get the needle jet to screw back in correctly.

The first picture shows how the emulsifiers were installed in the carb before i tried to switch them....It seems that one end of the nozzle is slightly smaller in diameter than the other, and this is the side that will fit easily into the hole.

However when I try to install the emulsifier with the larger (tapered) end facing up toward the throat of the carb, the needle jet doesn't screw in at all, as shown in the other picture.

Maybe i'm missing something here (probably lol) or maybe these arent the stock needle jets?? I verified the sizing and placement again on the carbs.
This small tube, part of ghe emulsifier assey, must be installed with the larger tapered hole upwards.
 

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Discussion Starter #7
This small tube, part of ghe emulsifier assey, must be installed with the larger tapered hole upwards.
OK, so from what you're saying I'm getting that when properly installed, the small tube should look like this in the carb. (for reference this is installing the tube with the tapered hole facing towards the needle jet assembly.....or installing the tube with the larger hole upwards while the carbs are upside down.)
Picture is attached.



Again thank you for all the help!
 

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I am unique
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OK, so from what you're saying I'm getting that when properly installed, the small tube should look like this in the carb. (for reference this is installing the tube with the tapered hole facing towards the needle jet assembly.....or installing the tube with the larger hole upwards while the carbs are upside down.)
Picture is attached.



Again thank you for all the help!
Since I can't see the pic on my phone I shall repeat. The tapered larger hole fits into the throttle bore so that the larger orifice of this emulsifier tube is up. When I say up it means in its normal operating position.
 

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Discussion Starter #9
Since I can't see the pic on my phone I shall repeat. The tapered larger hole fits into the throttle bore so that the larger orifice of this emulsifier tube is up. When I say up it means in its normal operating position.
So my bad on the terminology mis-hap. The emulsifier tube which has threads and is part of the main jet assembly...is installed right no matter what (there's only one way to put it in with the threads).

However the nozzle is where my question is. It's not brass...it is silver in color..has no threads...and has a shoulder in the middle of it. One end has a larger opening than the other.

If I am messing this terminology up I'm sorry! :chair:
 

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I am unique
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So my bad on the terminology mis-hap. The emulsifier tube which has threads and is part of the main jet assembly...is installed right no matter what (there's only one way to put it in with the threads).

However the nozzle is where my question is. It's not brass...it is silver in color..has no threads...and has a shoulder in the middle of it. One end has a larger opening than the other.

If I am messing this terminology up I'm sorry! :chair:
That tube or nozzle needs to have the larger opening up.
 

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Discussion Starter #13
That tube or nozzle needs to have the larger opening up.
Ok awesome, that's what I thought by what you said...so next question. Is there a specific way to install it? When i put it in the correct way, the emulsifier tube wont thread all the way in properly.
 

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Ok awesome, that's what I thought by what you said...so next question. Is there a specific way to install it? When i put it in the correct way, the emulsifier tube wont thread all the way in properly.
I had the same problem a while ago. The best advise I can give you is put it in straight as possible and start to screw in the main jet assembly really really slow and it will start push the emulsifier in. Now go nice and slow because I messed up a set of carbs this way because I went and tightened it without taking my time. It should screw in nice and smooth if you feel any type of friction stop back it out and pull the emulsifier back out and star all over. Take your time bro
 

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Ok awesome, that's what I thought by what you said...so next question. Is there a specific way to install it? When i put it in the correct way, the emulsifier tube wont thread all the way in properly.
The picture you show here is the correct way it goes into the carb, you should see this in the carb throat...........

 

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Discussion Starter #16
AWESOME!

Imagine that, things work when they are put in the right way!:D

Thanks everyone for the help and advice!
 

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Master of the Electron
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The large, tapered end of the nozzle faces into the throat - sounds like you had it backwards... it IS harder to install correctly - almost a press fit.
 
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