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I bought Mikuni jets and the head of them doesn't fit in the tube the old ones went into, do they need that tube or can I just screw them in and put my carb back on.....thanks
 

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Raptorstock - you're running the huge mains because you still have stock needles. With aftermarket needles (DJ, GYTR, etc.) you'll be down at 160 left, 165 right Mikuni mains, and transition across the full throttle range will be much smoother.

Typical suggestion for an open airbox is 160L/165R, aftermarket needles 1 notch rich of center, 25 pilots with screws at around 2 turns out.
That's good to know, was beginning to think my bike was a one of a kind fluke or something.
 

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what should i jet my quad i have a dg full system with uni filter..and cuts out should i got one size bigger on the main jets in each carb?
I have the same problem with a similar setup and would also appreciate an answer. Any information about how to choose the right needles, if i need aftermarket needles would be great too.
 

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I have the same problem with a similar setup and would also appreciate an answer. Any information about how to choose the right needles, if i need aftermarket needles would be great too.
Need to know what mods you have and what jetting you currently have.
 

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Its bone stock except for a White Bros R4 exhaust system. Stock intake with lid and snorkel. I think the jets are stock but i dont know for sure. The quad runs perfect up until 4th and 5th gear and then it loses all power and backfires sometimes. Then i have to shut it down and let it sit for awhile.
 

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Its bone stock except for a White Bros R4 exhaust system. Stock intake with lid and snorkel. I think the jets are stock but i dont know for sure. The quad runs perfect up until 4th and 5th gear and then it loses all power and backfires sometimes. Then i have to shut it down and let it sit for awhile.
So it's running lean. If only at full throttle up the main sizes. If also at part throttle raise the needles.
 

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I am new to the world of quads and need some help getting a starting point for the jetting for my Raptor. Specs are as follows....

2001 Raptor 660
102mm bore, 11:1 CP piston
Stock stroke
Stage 2 HotCams with Ferrea Stainless stock sized valves
Sparks X6 Big Core Full Exhaust (header/muffler), cermic coated header
ProDesign intake with Uni foam filter for the ProDesign intake
No air box lid

Typical riding location - Sierra Vista, AZ and Tucson, AZ
Elevation in Sierra Vista is 4000-4600 feet
Elevation in Tucson is 2000-2500 feet

Most riding will be in Sierra Vista, original jetting with stock engine worked perfectly fine at both elevations, no unusual performance or sounds, so I'm not super concerned with jetting for one or the other, but would prefer to have it set primarily for 4000-4600 feet elevation since that is where I ride the most.

This is my first quad so I really don't know much about jetting these carbs, I need something that is in the ball park to get it running for break in, and then I can go from there. I know how to tune, just never messed with one of these before.

Based on my reading, somewhere between 160 and 170 Mikuni mains would be a good starting point, and I would assume with pilot jets that the bigger the number the more flow they allow, so maybe 28 on the pilots? Standard 2.5-3 turns out on the screws. Is it wise to get new needles (needles being the adjustable ones that are located in the slide?) as well?
 

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I have about the same mods and im set for about 5000 elevation. Im running 160/165 mains, 25 pilots, and vitos needles on the 4th clip. You dont need any higher than 25 pilots. Fuel screws about 2 turns from seated.
 

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400ft
Stock motor
Prodesign clamp on foam filter....no lid
White brothers e-series no spark arrestor
Alba needles 3rd groove from the top
160/165 mikuni mains
25 pilots
Fuel screws left is 2 turns out right carb is 2 1/4th out..

I'm thinking I could turn the fuel screws in a lil and raise the clip a groove.
 

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2004 Yamaha Raptor YFM660R
Location : Indianapolis Indiana
Elevation: 799 ft.
Jet: Mikuni
Intake Mods: No lid w/ Uni filter and pro flow adapter
Exhaust: White Brothers MX4 Slip on that I packed the same time I jetted
Porting/Engine mods: Stock


Jetting: #25 for both pilots, 160/165 combo Dynojet mains,
Air Fuel screws: were left in exact position I found them in which I would assume is stock
Needle: Dynojet needles @ 3rd clip (middle)


Update: Bought a DMC Alien dual exhaust and headers are glowing red after a 20 minute hard ride. Will create a new setup for that to show differences when I figure out the difference.
 

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2004 Yamaha Raptor YFM660R
Location : Indianapolis Indiana
Elevation: 799 ft.
Jet: Mikuni
Intake Mods: No lid w/ Uni filter and pro flow adapter
Exhaust: White Brothers MX4 Slip on that I packed the same time I jetted
Porting/Engine mods: Stock


Jetting: #25 for both pilots, 160/165 combo Dynojet mains,
Air Fuel screws: were left in exact position I found them in which I would assume is stock
Needle: Dynojet needles @ 3rd clip (middle)


Update: Bought a DMC Alien dual exhaust and headers are glowing red after a 20 minute hard ride. Will create a new setup for that to show differences when I figure out the difference.
We got your old pipe on and just about got the jetting right ...pipe sounds great and the power feels good so far I'm going to change the jets again and mod the air box..
 

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Elevation-close to sea level
Jet type-Mikuni mains/Dynojet needles
Intake-Gytr,Gytr foam filter,No lid,port matched intake boots
Exhaust-Trinity stage 4
Motor-stock

Jetting
Pilots-25
Fuel screw-3 turns
Needle- 5th slot closest to the taper
Mains-185/190
Clear tube method float level adjustment with freeze float mod.

It finally runs good,still not perfect.I do not know why I have to use such huge jets and such a rich needle setting but thats what it takes to get this thing to run. The plug is a light to medium tan.
I may have to try this.. only thing I didn't do was matched the intake boots...would aftermarket boots match the ports?

Anyone know the difference from dj and alba needles?
 

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I may have to try this.. only thing I didn't do was matched the intake boots...would aftermarket boots match the ports?

Anyone know the difference from dj and alba needles?
all aftermarket needles are prolly pretty close to each other...i think some had 6 notches instead of 5.... i highly doubt switching needles from say vitos to alba would make a noticalbe diff in HP........ i think alba used dynojet needles or vise versa anyway....
 

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I thought they was the same... do you know of/ if any aftermarket intake boots would match the ports?

It feels like I should have more power at full throttle.... feels really good on the needles but at wot it seems it should pull more... should I go up to 170-175. from 160-165...
 

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mess around with the jetting.......i ran no air box, stock head, stage one cam and barkers.... with stock carbs, i ran like 180-185 mains.......it seemed to run the best with big mains.....
 

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mess around with the jetting.......i ran no air box, stock head, stage one cam and barkers.... with stock carbs, i ran like 180-185 mains.......it seemed to run the best with big mains.....
Even with aftermarket needles you ran 180-185?

If I remember correctly freez said 660s like to be a little rich.

Any idea why my clymer manual says the fuel screws should be 3 out L, 2 out R?
 

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dont listen to the manual on carbs jetting.... run freezs 3mm clear tube and modded floats... and yea i ran aftermarket needles...but was running barkers, which flow more... u could prolly go up to 175 or so... just remember that too rich is loosing HP......good luck. mess around with it.............:)
 
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