300/440/550 Js440 stock tune settings? Can't find them?

80degrees

80degrees

Location
Australia
I have a js440
it was compleatly stock and slow. I added a aftermarket dayjon exhoust and and air filter to try and get more power. It defiantly feels like it has. But after I fitted it I would get up on the plan and it felt like it was backing off then going again then backing off slightly. To me it felt like it wasn't getting enough fuel...

So silly me started playing with the screws.. Didn't quite work out.
I wana know what the stock settings are for the js440 or if u guys know what they would need to be with the mods I have?

Also what do u think my problem was?
 
80degrees

80degrees

Location
Australia
Very helpfully... But how to tell what model ski you have? I mean the engine could have been swapped in its time? Also adding an exhaust and air filter would this drasticly change those fuel settings?
 
Joker

Joker

...chaos? Its Fair!
Location
La Porte, Indiana
With what your running you could make it a little richer than stock and look at you hin and usually the last two numbers are the year. If not google your hin and it should give you a year
 
80degrees

80degrees

Location
Australia
[FONT=Tahoma, Calibri, Verdana, Geneva, sans-serif]Okay so today I tuned my ski a little starts fun. It drives fine although when I first start the ski and give it full throttle it bogs down then goes! Is this 2 rich or 2 lean? After it gets out the bog it's fine I can back off and give it again and it won't bog down. Only when I stop start and go it will do it?[/FONT]
 
Pnutt

Pnutt

From( Jet Punks ) Texoma
Location
oklahoma
IF you buy a service manual for the ski they are for all js skis from 81 to 91 it has specifice instructions on what to do i read it just cant remember if that means rich or lean i do know it tells you to let it idle and then adust it until it idles as fast as possible witch is in and then to hit the throttle and if it hessitates to turn it back out. you do that 1/8 turn and wait becaus eit takes it a few minuites to responde to the change.
 
screaming440

screaming440

The Old Skool Professor
Location
KC/Lake of The Ozarks
80degrees said:
[FONT=Tahoma, Calibri, Verdana, Geneva, sans-serif]Okay so today I tuned my ski a little starts fun. It drives fine although when I first start the ski and give it full throttle it bogs down then goes! Is this 2 rich or 2 lean? After it gets out the bog it's fine I can back off and give it again and it won't bog down. Only when I stop start and go it will do it?[/FONT]
Click to expand...

if it is only doing this at start up it is not likely an adjustment. it is likely loading or leaning cuz of something that occures when it is not running. here are a few ideas.

this is could be an early bn carb they dump the "float bowl" fuel when they sit. this causes them to load up when you restart and there is no fix for it.

it could also be a leaking neadle valve.

it could be something allowing fuel pressure to drop when you shut it down.

try and let it idle a little before you give it full throttle
 
Pnutt

Pnutt

From( Jet Punks ) Texoma
Location
oklahoma
mine all started like that but then i put on transparant fuel line and noticed the carb fuel presure back flowing when i stoped because none of the hoses where tight make sure you hose clamp them all or atleast use zip ties to keep the vacume and keep air out. makes for a faster start also .
 
You must log in or register to reply here.
Top Bottom