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Author Topic: What size main jets do i need?????  (Read 2013 times)

Offline Tribal_superman

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What size main jets do i need?????
« on: March 26, 2009, 11:11:16 PM »
I have an 02 raptor. I have a  power lid on the air boc, kan and  n airfilter, engine bored 30 over , ported, polished, kibble white valves, stage 2 cam, full yoshi pipe.  I am using  dial a jet jet kit for this quad but its running way to lean on the riches setting.  What size Main jets should I go with???

Offline Peelz

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Re: What size main jets do i need?????
« Reply #1 on: March 26, 2009, 11:35:29 PM »
what size you got in there now? I would guess 170-ish on Mikuni jets.
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Offline dragonz

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Re: What size main jets do i need?????
« Reply #2 on: April 01, 2010, 09:02:03 PM »
I have 200's (2.00mm) in mine & still working on it to get all the wrinkles out.
Was too lean with 195's
2003 Raptor 660LE
719cc with Kenz 13.5:1 piston
X-4 cam & no decomp
39mm FCR's
HV ported head
Ferrea SS Valves
CT Sonic Exhaust
GYTR Clutch

ASR +3+1 A-Arms & Works Tripple Rates
450 Front Calipers
+2 Extended Swingarm
G-Force Axle & Hubs.
Pro Armour Skid Plate
Tusk Nerfs


Gonna be a fun ride now!

Offline dragonz

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Re: What size main jets do i need?????
« Reply #3 on: April 04, 2010, 08:09:42 PM »
Disregard my last post, & if you are interested, read my Mis-fire blues post to understand why.

What needles are you running, the standard needles will restrict the gas at top-end too much.
If you haven't already, get a set of Dynojet needles or similar.
Put them in & then start playing with your mains from there.
I would suggest 170/175 (Mikuni) as a good starting point
Mikuni Jets are sized in millimetres.
so 170 = 1.70mm
    175 = 1.75mm

Dynojets are sized according to flow, so there sizing is completely different
2003 Raptor 660LE
719cc with Kenz 13.5:1 piston
X-4 cam & no decomp
39mm FCR's
HV ported head
Ferrea SS Valves
CT Sonic Exhaust
GYTR Clutch

ASR +3+1 A-Arms & Works Tripple Rates
450 Front Calipers
+2 Extended Swingarm
G-Force Axle & Hubs.
Pro Armour Skid Plate
Tusk Nerfs


Gonna be a fun ride now!