Carburetor (specs) Database: SuperJet and Blaster 1

[Kjacob04]

Are you using a Stock OEM 760 Manifold? Did you block the Crossover Passage?

Are the Choke Butterflies still in the Carbs? Are you Sparkplugs Friend?

That High Speed Screw should be around 1+ turns. A Quarter Turn seems Lean...

Find someone who is good at tuning skis to help you.

The Low End Throttle should have the Ski jump out of the Water and snap your Neck back after kneeling and idling for around 10 seconds, then pulling the Throttle hard. Adjust Low Speed Adjuster Screw until you get this response. Do not touch the High Speed Screws until this Step is completed.

Once you have that instant crispy response, then you move on to dialing in the High Speed Screws. The High Speed Adjustment is a matter of finding the Highest RPM in short 100 ft WOT flat water pump-hooked-up sprints, then finish tuning by enriching (opening) the High Speed Adjustment Screw a little (1/8) too achieve a margin of safety.

I have an aftermarket boysen intake with speed plate and rad valves. Carbs are brand new retail mikuni 44s. Plugs are black/dark brown in color, haven't taken a look at piston wash yet tho. I went thru the progressions of checking my throttle response and I'm definitely lean with either my pop off or pilot jet. When I hold the ski at quarter throttle for 20 sec then stab the throttle it falls on it face then revs up. Turning the low speed screw out helped cover up this hesitation. I think I have a scenario of a lean pilot, rich main but I'm going to make one change at a time and will post the results

 

[waxhead]

you low speed jet is very small for a performance tune

 

[fastgtfairlane]

On your Post #459 you said the Carbs were OEM not Retail!

Brand = Mikuni
Model = OEM
Size = 44mm

OEM means Factory Yamaha Mikuni Carbs. They are different from the Aftermarket Mikuni Carbs.

It's hard to give accurate advice if you give misleading or incomplete info...

Yes indeed. The retail Mikunis flow more fuel and will require different jetting. I have drilled the returns and run a 80 main jet as thr restrictor on my carbs

 

[Kjacob04]

On your Post #459 you said the Carbs were OEM not Retail!

Brand = Mikuni
Model = OEM
Size = 44mm

OEM means Factory Yamaha Mikuni Carbs. They are different from the Aftermarket Mikuni Carbs.

It's hard to give accurate advice if you give misleading or incomplete info...

Ohh man, I totally screwed up on that one. I got them switched around with reading this thread 4 times over

 

[kevbo]

On your Post #459 you said the Carbs were OEM not Retail!

Brand = Mikuni
Model = OEM
Size = 44mm

OEM means Factory Yamaha Mikuni Carbs. They are different from the Aftermarket Mikuni Carbs.

It's hard to give accurate advice if you give misleading or incomplete info...

The most accurate advise on jetting? Whats in my carbs probably won't work in yours. Learn how to tune!

 

[fastgtfairlane]

The most accurate advise on jetting? Whats in my carbs probably won't work in yours.

This right here

 

[waxhead]

On your Post #459 you said the Carbs were OEM not Retail!

Brand = Mikuni
Model = OEM
Size = 44mm

OEM means Factory Yamaha Mikuni Carbs. They are different from the Aftermarket Mikuni Carbs.

It's hard to give accurate advice if you give misleading or incomplete info...

yeah any advice I gave you on these is incorrect now

 

[TheBuzzard]

This is what worked perfectly and added power top and bottom over a single Novi 48 on a 96 superjet ported to the moon. Threw on oem duals from a 760 and jetted with this. Stock intake, carbs, airbox with carbon tech reeds. B pipe

 

[rob-noten]

Can you guys advice me on some jetting.
Superjet

Ported 760
Ada 38cc domes
Dual novi 44 d boosters with novi external fuel pump.
Protec exhaust
Am flame arrestor
Msd 144 mag pump bla bla.....

 

[afraz1er]

Can you guys advice me on some jetting.
Superjet

Ported 760
Ada 38cc domes
Dual novi 44 d boosters with novi external fuel pump.
Protec exhaust
Am flame arrestor
Msd 144 mag pump bla bla.....

Message me tomorrow Rob

Sent from my moto g power (2022) using Tapatalk

 

[loictahiti]

Hi guys happy Valentine day
I m looking some help for jetting a single Novi power bomb 48 ,
Bolt on FR2Evo with
840 +6 , 85 flat Kawi piston , msd cdi,64x igniter, type B, Vforce 3, 148 solas pump with 9/14 STK impeller,
Just replace twin 38 for this 48 for easy maintenance and E box access for Freeride.
Let me know if you have some idea thks

 

[bigair1080]

I am building a 61x 84mm with 64x cases. Stock dual 38 carbs. Stock flame arrestor. I am looking for a starting point for carb jetting.
cases and cylinder are ported. Ada head 38cc 760 domes, Bpipe, Zeel. 144 pump with 9/15. From reading a lot of posts it looks like 75p 135m 43-55 pop off
any help would be greatly appreciated.

 

[fastgtfairlane]

Might also consider a 77.5, 80 pilots and 137.5, 140 mains to get it dialed. The jetting you listed is more for a stock 701 with a pipe a head, possibly msd. Depending on who did the porting they should be able to give you some carb specs.

 

[yellowsuperjet36]

I have a 760 with ADA head (40mm dome), PHP intake, dual 46s, AM flame arrestors, a protec pipe, lightened fly wheel and a zeeltronics tune. About to drop it in my SN with a mag pump 144m. Does anyone have any suggestions on where to start with jetting, needle seat and pop off?

 

[joeschuit]

I have a 760 with ADA head (40mm dome), PHP intake, dual 46s, AM flame arrestors, a protec pipe, lightened fly wheel and a zeeltronics tune. About to drop it in my SN with a mag pump 144m. Does anyone have any suggestions on where to start with jetting, needle seat and pop off?

2.0 needle/seat with 80 or 95 gram spring to get you 20-25psi popoff. 125 pilot, 110 main. 1 turn out on low and high screws. depending on how well your cases/ports flow at low speed you might need to lean out the low speed jet.

 

[HollaHolla]

This will be a fun one...

Dual FS 49s w/ JM781
*PowerFactory Laydown Dry Pipe*
155 Skat Pump with 6/12 cutback 3 prop
MSD Enhancer (62T Zeel coming later) / Lightened Flywheel
Carbon Freestyle Hull (T1)

Will post what I find out to make my contribution here.....if it can work enough to be worth going 49s over 44s for the extra bit of power)
Any known knowledge/tips/input...let em rip while I figure this one out....unless a crazy person already has which would be just superduper.

 

[TehXshizzit]

Whats everyone running for their 760 lites boat set ups? 62t/760 sbn38s with ignition and 10/16 prop

Right now I'm at 135 main, 75 pilot, 2.0NS at 30psi

Runs good but seems like it could use more maybe?

 

[Freakie]

I have been running 140 mains and 75 pilots on my JM 781 dual 38s for a while mostly surf and free stryle....30 psi pop off.......did some WFO runs on a river dash 2 weeks ago and stuck both pistons....evidence shows both cylinders are way too lean at WFO....ski ripped around bouys forever though .....going to 80 and 145s now on rebuild

 

[kevbo]

I have been running 140 mains and 75 pilots on my JM 781 dual 38s for a while mostly surf and free stryle....30 psi pop off.......did some WFO runs on a river dash 2 weeks ago and stuck both pistons....evidence shows both cylinders are way too lean at WFO....ski ripped around bouys forever though .....going to 80 and 145s now on rebuild

That’s what following other people’s jetting advice will get you!

 

[MiNDRiVE]

Searched the thread, couldn't find my exact setup but this one seemed close, looking for any additional input anyone might have.

Brand = Mikuni
Model = OEM
Size = 38mm
F/A= Stock
Quantity = 2
Main Jet = 135
Pilot Jet = 72.5
Needle/Seat = 1.5(55psi)
Spring = 115
Pilot screw = 1 1/4 turn out
Main Screw = 1 1/2 turn out
- - - - - -
Gas Octane = 87 (ethanol added poop fuel)
Altitude = 538 feet above sea level
Main type of riding = Freestyle, chasing boats
Powerband = Bottom to mid
Motor type/setup = 2017 62T SJ ( limited bpipe, worx 201, bone stock everything else)


Thanks!