need help with jetting

[The Penguin]

picked up a 61x/61x today and want to throw it in my square next weekend.

I don't want to crack the e-box so I'll be using the stock 6m6 CDI for the time being (I know, I should disable the rev limiter - but this is a temporary installation until I get my other ski done)

so - It's a stock 61x, with a Mikuni 44mm carb, Ocean Pro flame arrestor, 6m6 electronics, and a Riva pipe (similar to this one: http://i268.photobucket.com/albums/jj39/shift1313/Jet Ski/Jul27_02.jpg except the exhaust outlet is toward the front of the ski)

The main jet is currently a 115

is there a number on the smaller jet?

suggestions on what I need to change the main to?

Thanks!

 

[Mike W]

Here is the jetting I had in my old SN with the same Riva pipe:
145 main (1 1/2 turn out)
120 pilot (1 1/4 turn out)
95 gm spring
2.3 n/s

Look on the side of the pilot jet. That is there you will see the jet size. It is very hard to see so I use a magnifying glass.

 

[The Penguin]

how do figure out what the spring and n/s are?

and where are they? :biggrin:

 

[Mike W]

how do figure out what the spring and n/s are?

and where are they? :biggrin:

When you take the diaphram cover off and take out the diaphram, the spring and needle and seat are on the left side of the carb. You will see it.

Springs:
65 gm: Shiny silver
85 gm: Black
95 gm: Dull silver
115 gm: Gold

 

[#ZERO]

If you pull the seat out it has a small number stamped on the bottom and the pilot jets are stamped on the side.

You can check the pop-off pressure with a tester and compare it with the chart below if you're uncertain about the spring color.

 

[The Penguin]

OK - this is what it currently has:

115 Main
120 Pilot
65gm spring (looks shiny to me, and it's a pretty flimsy spring)
1.5 n/s

as a reference, it looks like Factory Pipe recommends

145 main
120 pilot
stock n/s (what size is that?)
95gm spring

suggestions?

 

[Mouthfulloflake]

thats the leanest jetting ive ever seen in a single carb before.

120/140 or 120/145 with 2.0 Needle and seat ( stock is 1.5) and a 95 gram spring are right in the ballpark it seems for most single carb applications.

Its performing less than stellar on my B pipe boat right now though,

 

[The Penguin]

hey MFOL - check your thread.

the carb I'm using on this motor came off a 650 that I bought from someone a couple years ago, so I have no idea why it is jetted the way it is.

 

[Mouthfulloflake]

I gotcha... maybe thats stock 650 jetting..

ive never messed with a stock 650 carb.

thanks for the link on the other thread, that led me to MANY other search words.