Raptor running lean - Yamaha Raptor Forum
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post #1 of 2 (permalink) Old 08-09-2019, 01:43 PM Thread Starter
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Join Date: Aug 2019
Posts: 1
Raptor running lean

Hey guys brand new to the raptor forum glad to join you. I have an 04 raptor i purchased about a month or two ago. Came with stock exhaust , a gytr pro flow air filter and as i was breaking down the carbs i realized someone put a 22.5 pilot and a 25 pilot in the other carb .ran like shit compared to a healthy running raptor. I noticed the rear bearings were seized to the axle so i decided to rip it all apart and upgrade.

dynojet stage 2 kit
ct racing full exhaust w/ fresh pack
new petcock/fuel filter
new pro design pro flow air filter
EHS racing airbox lid
tusk extended axle +6
alba nerf bars
alba rear disc
did x ring chain 520
sunstar 12 tooth front sprocket 40 tooth rear

I had the 146/148 main jets installed and I was waiting for my EHS racing lid to come in so i decided to run it with the stock lid to get it somewhat tuned in . But i had to adjust the fuel mixture screws way out like 6+ turns to finally get a rich plug.I put the 148/150 in and that seemed to help with the WOT spark plug color. but not the ground strap which was still light grey/ grey.( i know main jets won't affect ground strap color)

So now i have two 25 pilots in the mail coming to hopefully solve this fuel issue. Since everyone says thats an issue thats pretty common. I also am ordering two 27.5 pilot jets just to be safe. i also ordered some vitos fuel mixture screws with the knobs on the end for easier adjustment(in brass)

I moved the needle clip to the 4th position as well , haven't tried it yet

Once i get the 25 pilots in i will update.

Id rather start with too much fuel a dial back then not enough fuel and mess things up.

Any suggestions?

new setup will be

dynojet mains 148/150
mikuni pilot jets #25 both sides or 27.5s

im at 725ft elevation wise
I run premium 93 mobil gas in it
15w50 yamalube oil
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post #2 of 2 (permalink) Old 08-12-2019, 12:53 AM
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Join Date: Apr 2007
Location: San Diego, CA
Posts: 14,431
Forget plug color...

With airbox open you want mikuni 160-L/165-R (or DJ 146/148 ), DJ needles (MUST use these!) around 1 notch high of center, 25 pilots and screws about 2.5 turns out. If you don't use the DJ needles you either end up going way too high on mains or on fuel screws but you never get good transitions across middle throttle.

Tune mains at 3/4 to full throttle, needles at 1/4 to 3/4 and fuel screws for idle to 1/4.

BTW, welcome to the forum!

'01 660 Raptor, Burgard +2+1 arms, YFZ Shocks, LSR anti-vibe, CTR pipe, jetted, K&N
'01 Polaris Scrambler 400, K&N
'02 Honda 400ex, Big Gun pipe, jetted, K&N, Lonestar +2 A-arms, Lonestar anti-vibe
'04 Suzuki LTZ400
'16 RZR XP4 1000 Turbo

Last edited by QuadManiac; 08-12-2019 at 01:12 AM.
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