how to jet properly

nshalaby

nshalaby

Location
Kawkawlin, Mi
I need some help trying to jet my 44sbn to my 650. My ski just isnt running with the throttle response that it should have with all of its mods. Right now it has the following: Ocean pro swirl head, .50 bored over, westcoast pipe, 44sbn, and skat trak impeller. I pulled the plugs off and they were really dry and it never fires right away like it should and its quick to bog down, im guessing that this is the problem but if you guys have any ideas that would help too. thanks
 
SuperJETT

SuperJETT

So long and thanks for all the fish
Location
none
Have you read through the Mikuni manual yet?

You start at the bottom and work your way up.

1. idle screw/low adjuster
2. popoff
3. low jet
4. high jet
5. high adjuster

However, if you're way off on something, it can cause problems with the entire tuning process.

Also, is it a regular Mikuni carb or is it off a Yamaha/other manufacturer?
 
nshalaby

nshalaby

Location
Kawkawlin, Mi
no it came off of a x2 but was sitting for awhile, i bought a rebuild kit for it and put the jets in exactly how they were but like i said the ski just doesnt seem right, can i download the manual? thanks
 
SuperJETT

SuperJETT

So long and thanks for all the fish
Location
none
Carb not assembled properly, exhaust leak, bad tuning, could be tons of things---your description is fairly vague.
 
Speedfreak

Speedfreak

Location
So. IL
I would start from scratch and do a leak down test first to make sure it is tight. Then rebuild the carb again. Make sure that you spray carb cleaner through the low speed jet so that the idle jets are all clean and then do it again. The majority of carb problems that I work on someone else tried to clean them first and didn't do a very good job.
 
nshalaby

nshalaby

Location
Kawkawlin, Mi
The carb is fine as far as being rebuild correctly, now i just replaced a pipe hose that was leaking on me. Now there is a slight leak towards the top of the head that i will have to fix but i just bought a new gasket and torqued the head bolts down correctly how would this happen. Compression in my eninge is also lowing than what i expected like 125psi.
 
K

Kennay

Squarenose for the _____
Location
Myrtle Beach, SC
From back when I put one on my six fiddy when I had it..... here is what I played around with and got to work the best



Westcoast pipe
~160lbs of compression
44mm SBN
Skat trak 9/17 (I think)

Needle and seat are a 2.3
pilot jet is a 120
main jet is a 160
65g chrome spring
 
K

Kennay

Squarenose for the _____
Location
Myrtle Beach, SC
and I just read your other response.... 125psi? That is way low for an aftermarket head, hell, that low for a stock head. How thick of a head gasket are you running? 125psi alone might make it run pretty shatty. Are you sure your gauge is correct?

How long has it been since a new topend has gone into that thing? 125 dead even in both holes?
 
nshalaby

nshalaby

Location
Kawkawlin, Mi
Yea 125psi in both, i thought that was really low, like i said the ski has no throttle response to it. I just bought a new gasket kit and put them all on when i had the enigne out. I purchased the engine as a whole recently so i was told the basic specs. of it.
 
nshalaby

nshalaby

Location
Kawkawlin, Mi
If for some reason the ski still doesnt run right is there a possiblity of someone being able to help me out? Im in Mid-Michigan, or if someone is going to go to jam at the dam if they could look at it there? I would also pay if someone had to meet up with me. thanks
 
SuperJETT

SuperJETT

So long and thanks for all the fish
Location
none
nshalaby said:
If for some reason the ski still doesnt run right is there a possiblity of someone being able to help me out? Im in Mid-Michigan, or if someone is going to go to jam at the dam if they could look at it there? I would also pay if someone had to meet up with me. thanks
Click to expand...

Maybe freestylegeek, he's around Grand Rapids.

There are tons of Michiganders on here, I'm sure someone can help.
 
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