SX/SXi/SXi Pro jetting twin 46 mukunis

[Jayski]

Hoping someone could help me out- trying to jet my twin 46mm mukuni's they are RIVA modified (i think) anyway the jetting is way out was on a crazy fast raceboat.

Twin 46 mukunis on R&D manifold
Fresh 779cc with full porting (exhaust and inlet) 2mm over
Comp is currently at 195 (but might bring that down to the 180ish) its a lee's head
V-force reeds with spacers
factory pipe with sxr chamber (front exit no waterbox)
lightned flywheel- 650 electrics

Use for the boat is all freeride- dont get it on WOT to much-

 

[ratboy120206]

what are the symptoms? and current jetting? if the ski stalls your lean, if it blubbers your fat? if it helps any with dual 44's i had jetting at 115L 155H! should give you a better starting point!

 

[Jayski]

what are the symptoms? and current jetting? if the ski stalls your lean, if it blubbers your fat? if it helps any with dual 44's i had jetting at 115L 155H! should give you a better starting point!

was in a raceboat with a dry pipe etc.. its as rich as hell- the jets have been drilled out, it runs on the lows and highs fully shut and the high is still to fat.

 

[ratboy120206]

sounds like you got it figured out, get smaller jets!

 

[Jayski]

j

sounds like you got it figured out, get smaller jets!

yeh well thing is im not sure if they are small jets drilled out or fat jets drilled out so the marking on them means nothing.. what are others running?

 

[keith t]

I run K&N filters with socks , 120/115 jets 2.0 needle seats, and dull silver springs - gives 26psi pop off

very similar spec engine/ ski to yours - hits pretty good, should give you a start point if mothing else

(superjet BTW)

 

[Jayski]

So i pulled the jets out and i have 145 lows and 145 highs- I want nice crisp bottom end!

 

[Jayski]

I run K&N filters with socks , 120/115 jets 2.0 needle seats, and dull silver springs - gives 26psi pop off

very similar spec engine/ ski to yours - hits pretty good, should give you a start point if mothing else

(superjet BTW)

whats the difference in mods?

 

[SUPERTUNE]

Hoping someone could help me out- trying to jet my twin 46mm mukuni's they are RIVA modified (i think) anyway the jetting is way out was on a crazy fast raceboat.

Twin 46 mukunis on R&D manifold
Fresh 779cc with full porting (exhaust and inlet) 2mm over
Comp is currently at 195 (but might bring that down to the 180ish) its a lee's head
V-force reeds with spacers
factory pipe with sxr chamber (front exit no waterbox)
lightned flywheel- 650 electrics

Use for the boat is all freeride- dont get it on WOT to much-

Are these RIVA Powerbomb carbs? You say modified by RIVA, what does that exactly mean? Taper bored? Returns bleeds drilled out?
The spec's I sent you are for standard aftermarket Mikuni's.

 

[Jayski]

Are these RIVA Powerbomb carbs? You say modified by RIVA, what does that exactly mean? Taper bored? Returns bleeds drilled out?
The spec's I sent you are for standard aftermarket Mikuni's.

yeh they are Taper bored.. Not sure if returns are drilled out, cannont bold up a standard filter only a torsetti or something..

I would assume they are powerbombs-- Just bought them of an x race ski..

jet them different?

 

[Matt_E]

Not sure if returns are drilled out

Take the fuel pump blocks off the carbs and see if there is a very small hole or a big hole in the return passage.

 

[Jayski]

Take the fuel pump blocks off the carbs and see if there is a very small hole or a big hole in the return passage.

Well did all the riva have returned drilled and why would you want the returnes drilled out?? I put a jet in the R-line to restrict it a bit-- Is the powerBOMB a 46 or 48?, how do i know thats what i have?? ? havent toyd much with jetski carbs..

 

[Matt_E]

A Powerbomb is a 48 carb.
Some aftermarket carb makes drill out the return restriction so that the fuel pressure can be fine-tuned by replaceable jets in the return line.

I put a jet in the line to restrict the returned a bit

What size jet did you put in?

 

[Jayski]

ahhh i see- I put one in out of the shed.. didnt even look @ it.. whats recomended??

 

[Matt_E]

Depends on the carbs. I used to use a #60 main jet for a Powerbomb and also for older 48 Full Spectrums.

You need to find out 1) if they are internally restricted, and 2) what the size of the restrictor is.

 

[Jayski]

Depends on the carbs. I used to use a #60 main jet for a Powerbomb and also for older 48 Full Spectrums.

You need to find out 1) if they are internally restricted, and 2) what the size of the restrictor is.

Or c... findout what jet they guy had in the raceboat?? I assume id run the same? right? cause he deff had one in there..

thanks fr your help MATT.. hopfully ill be able to sort these suckers out!

 

[Boris]

Why "no waterbox" ?

 

[Jayski]

Why "no waterbox" ?

using sxr factory chamber in a gen one X2... theres no space to rivirt it back through the box- I put one of thoese small hotdog ones in.. but didnt plumb water into it it.. water is intruduced from the header and the stinger.