300/440/550 Do I need to rejet a SBN44 when swapping from a 650sx to 550?

ger87410

ger87410

How did I get here?
Location
Fort Worth
1989 550.

I'm getting a SBN44 for it that came off a 650sx.

Do I need to rejet it?

Anyone know what size jets I need?

Can I get a jetting kit for her?

Thanx!!!
G
 
3wheelerdude

3wheelerdude

Talk less, Ride more!
Location
Ontario Canada
I bought a 44sbn not long ago and from a thread on pwctoday and some advice form here, I jetted it to 120 low and 175 High. The river is still frozen so I cant really test yet.
 
ger87410

ger87410

How did I get here?
Location
Fort Worth
Thanx for the reply!

Canada, huh? You're not going to be able to test for another couple of months. I'm glad I don't live up there.
 
SQUARE JOEL!!!

SQUARE JOEL!!!

Location
Look for me when you see me coming!
ger87410 said:
1989 550.

I'm getting a SBN44 for it that came off a 650sx.

Do I need to rejet it?

Anyone know what size jets I need?

Can I get a jetting kit for her?

Thanx!!!
G
Click to expand...

The jetting would depend on what mods are on the 550. Based off of that and what jets are in the SBN now is your starting point. No one can guess what jets you need without knowing mods. Jets are sold individually. You'd prolly find much more info on PWC T.
 
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ger87410

ger87410

How did I get here?
Location
Fort Worth
Thanx for the reply!!!

It's got dual cooling.
I think it's ported, but not sure. How do you tell?
Mariner pipe.
Supertrapp waterbox.


I believe you're saying whether or not I need to change the jets depends on what's already in there. Is the numbers printed on the jets?
 
Scraggly

Scraggly

Location
hhh
ger87410 said:
Thanx for the reply!!!

It's got dual cooling.
I think it's ported, but not sure. How do you tell?
Mariner pipe.
Supertrapp waterbox.


I believe you're saying whether or not I need to change the jets depends on what's already in there. Is the numbers printed on the jets?
Click to expand...

they are stamped and hard to read. i had to get a magnifying glass with a light to read the jet stamps.
 
SQUARE JOEL!!!

SQUARE JOEL!!!

Location
Look for me when you see me coming!
Yes, the numbers are on the jets.

The DC won't really matter. More along the lines of exhaust and intake flow. Are you running the stock flame arrestor???? If so, I'd swap that jaunt out for something else.

If specs on porting are unknown...about the only way to tell is to eyeball it or measure.

What else are you doing to this 550? Advancing timing? Pump work? Higher compression?
 
ger87410

ger87410

How did I get here?
Location
Fort Worth
Thanx for the replies, guys!!!

I ain't doing a dang thing to it but try to get it to run more reliably. It's got the stock carb and arrestor on it now and she's unreliable when trying to maintain top speed. She'll cough and sputter a little, but won't die.

I don't like the BN carbs anyways. I'm familiar with the SBN carb and like that.

I'm not trying to race, do tricks, or anything else fancy. I'll settle for riding without breaking down.
 
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